Document:

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                                LEASE AGREEMENT

                                    Between

                       S.W. Austin Office Building Ltd.,

                                  as Landlord,

                                      and

                           Silicon Laboratories, Inc.
                            a Delaware corporation,

                                   as Tenant,

                Covering approximately 37,800 gross square feet
                            of the Building known as

                            Austin Industrial Center

                                   located at

                             4609 Southwest Parkway
                              Austin, Texas 78735.

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STANDARD INDUSTRIAL LEASE AGREEMENT

                                          Approximately 37,800 gross square feet
                                                1609 Southwest Parkway Suite 100
                                                             Austin, Texas 78735

                                LEASE AGREEMENT

THIS LEASE AGREEMENT is made and entered into by and between S.W. AUSTIN
OFFICE BUILDING, LTD., A TEXAS LIMITED PARTNERSHIP, hereinafter referred to as
"LANDLORD", and SILICON LABORATORIES, INC., A DELAWARE CORPORATION, hereinafter
referred to as "TENANT".

PREAMBLE

        Landlord intends to construct an office/warehouse building containing
approximately 37,800 square feet of space (the "BUILDING") on the tract of land
located at 4609 southwest Parkway, Austin, Texas, legally described on EXHIBIT
"A" attached hereto and incorporated herein by reference for all purposes (the
"PROPERTY"), together with certain exterior and interior amenities and features
(collectively, the "PROJECT"). Landlord intends to construct the Project
substantially in accordance with the Plans for the Project (hereinafter
defined). The term "PROJECT" shall mean the base building, all parking areas,
exterior features and amenities as reflected on the Plans for the Project and
all common area interior finishes, as generally set forth on EXHIBIT "B"
attached hereto. The term "PROJECT" does not include the finish out or
improvements to the tenant spaces in the Building. The completed construction
drawings and plans and specifications for the Project shall be referred to
herein as the "PLANS FOR THE PROJECT". The Plans for the Project shall be based
on the schematic plans and specifications attached hereto as EXHIBIT "B" and by
this reference made a part hereof.

1, PREMISES AND TERM. In consideration of the mutual obligations of Landlord
and Tenant set forth herein, Landlord leases to Tenant, and Tenant hereby takes
from Landlord, certain leased premises situated within the County of Travis,
State of Texas, as more particularly described on EXHIBIT "A" attached hereto
and incorporated herein by reference (the "PREMISES"), to have and to hold,
subject to the terms, covenants and conditions in this Lease. The term of this
Lease shall commence on the Commencement Date hereinafter set forth and shall
end on the last day of the month that is eighty-four (84) months after the
Commencement Date.

        A. EXISTING BUILDING AND IMPROVEMENTS. If no material improvements are
to be constructed to the Premises, the "COMMENCEMENT DATE" shall be October 1,
1998. In such event, Tenant acknowledges that (i) it has inspected and accepts
the Premises in its "as is" condition, (ii) the buildings and improvements
comprising the same are suitable for the purpose for which the Premises are
leased, (iii) the Premises are in good and satisfactory condition, and (iv) no
representations as to the repair of the Premises nor promises to alter, remodel
or improve the Premises have been made by Landlord (unless otherwise expressly
set forth in this Lease).

         B. BUILDING OR IMPROVEMENTS TO BE CONSTRUCTED. If the Premises or part
thereof are to be constructed, the Commencement Date shall be deemed to be the
earliest of: (i) the date upon which the Interior Improvements (defined on
EXHIBIT "C" attached hereto) to Premises which are to be erected in accordance
with the Interior Improvements Plans (defined on EXHIBIT "C" attached hereto)
have been substantially completed; (ii) the date on which the Interior
Improvements to the Premises would have been substantially completed but for
delays caused directly or indirectly by Tenant, including Interior Improvements
Plans delays or change orders; or (iii) the date on which Tenant occupies any
part of the Premises. Landlord and Tenant anticipate that the Premises and the
Interior Improvements will be substantially complete by November 18, 1998. As
used herein, the term "SUBSTANTIALLY COMPLETED", "SUBSTANTIALLY COMPLETE" and
"SUBSTANTIAL COMPLETION" shall mean that, in the opinion of the architect or
space planner that prepared the Interior Improvements Plans, such improvements
have been completed in accordance with the Interior Improvements Plans, the City
of Austin has issued a temporary certificate of occupancy for the Premises and
the Premises are in good and satisfactory condition, with the exception of
completion of minor details of construction, mechanical adjustments or
decorations which do not materially interfere with Tenant's use of the Premises
remain to be performed (items normally referred to as "PUNCH LIST" items).
Landlord and Tenant shall complete one punch list inspection and Landlord shall
complete and/or correct such punch list items within a reasonable period of time
after such inspection. As soon as the Interior Improvements have been
substantially completed, Landlord shall notify Tenant in writing that the
Commencement Date has occurred; provided, however, that in no event will the
Commencement Date occur prior to October 1, 1998 (unless Tenant occupies the
Premises prior to October 1, 1998), without the written consent of Tenant.

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        C. PARKING. Tenant and its employees, customers and licensees, in
common with Landlord and Landlord's agents, employees, contractors and
subcontractors, shall have the right to use for automobile parking the
entirety of the parking areas constructed for the Project, subject to (i) all
rules and regulations promulgated by Landlord, and (ii) rights of ingress and
egress of others as designated by Landlord. Subject to the foregoing and any
applicable laws and ordinances, Tenant may additionally park on any private
streets which are included in the Project. Landlord shall not be responsible
for enforcing Tenant's parking rights against any third parties and Tenant
expressly does not have the right to tow or obstruct improperly parked
vehicles. Tenant agrees not to park on any public streets adjacent to or in
the vicinity of the Premises.

2.      BASE RENT, SECURITY DEPOSIT AND ESCROW DEPOSITS.

        A. BASE RENT. Tenant agrees to pay Landlord rent for the Premises, in
advance, without demand, deduction or set off, at the rate of thirty-seven
thousand eight hundred dollars ($37,800.00) per month during Year 1 of the
initial term hereof, thirty-seven thousand eight hundred dollars ($37,800.00)
per month during Year 2 of the initial term hereof, thirty-seven thousand
eight hundred dollars ($37,800.00) per month during Year 3 of the initial
term hereof, thirty-nine thousand three hundred seventy-five and No/100
dollars ($39,375.00) per month during Year 4 of the initial term hereof,
thirty-nine thousand three hundred seventy-five and No/100 dollars
($39,375.00) per month during Year 5 of the initial term hereof, forty
thousand nine hundred fifty and No/l00 dollars ($40,950.00) per month during
Year 6 of the initial term hereof and forty thousand nine hundred fifty and
No/100 dollars ($40,950.00) per month during Year 7 of the initial term
hereof. One such monthly installment, plus the other monthly charges set forth
in Paragraph 2C below, shall be due and payable on the date hereof, and a
like monthly installment shall be due and payable on or before the first day
of each calendar month succeeding the Commencement Date, except that all
payments due hereunder for any fractional calendar month shall be prorated.

        B. SECURITY DEPOSIT.

                (i) CASH PORTION OF SECURITY DEPOSIT. Tenant agrees to deposit
        with Landlord on the date of execution hereof the sum of one hundred
        thirteen thousand four hundred and no/100 dollars ($113,400.00), which
        shall be held by Landlord, without obligation for interest, as partial
        security for the performance of Tenant's obligations under this Lease.

                (ii) LETTER OF CREDIT PORTION OF SECURITY DEPOSIT. Prior to
        the commencement of construction of the Interior Improvements, as an
        additional Security Deposit, Tenant shall provide Landlord with an
        irrevocable letter of credit (the "LETTER OF CREDIT") in the amount
        of $453,600.00 issued by a bank acceptable to Landlord, naming
        Landlord as the Beneficiary thereof. The Letter of Credit shall
        provide that Landlord may draw the full face amount thereof upon the
        presentation of the original of the Letter of Credit together with a
        sworn affidavit by Landlord (or an officer of Landlord) stating that
        Tenant is in default hereunder and that all cure periods relating to
        such default have expired. The Letter of Credit shall also provide
        that it may be drawn in full by Landlord in the same manner if at any
        time prior to the expiration of this Lease the Letter of Credit is
        within thirty (30) days of expiring and a replacement or extension
        thereof has not been furnished to Landlord. The Letter of Credit,
        including, without limitation, the form thereof, and all extensions
        and renewals thereof, shall otherwise be acceptable to Landlord in
        all respects. Tenant covenants to continuously keep the Letter of
        Credit in full force and effect and failure to do so shall constitute
        an Event of Default hereunder. The Letter of Credit shall be
        assignable and transferrable to Landlord's mortgage lender. In the
        event Landlord ever draws on the Letter of Credit, Landlord may
        thereafter retain all proceeds thereof in the form of cash in the
        same manner as the funds deposited with Landlord under paragraph
        2B(i) hereof and Landlord shall have no obligation to refund such
        proceeds in exchange for a replacement Letter of Credit.

                (iii) SECURITY DEPOSIT GENERALLY. The term "SECURITY DEPOSIT",
        when used in this Lease, shall mean the cash portion of the Security
        Deposit as described in paragraph 2B(i), above and/or the Letter of
        Credit portion of the Security Deposit as described in paragraph
        2B(ii), above. It is expressly understood and agreed that the Security
        Deposit is not an advance rental deposit or a measure of Landlord's
        damages in case of Tenant's default. Landlord may commingle the
        Security Deposit with Landlord's other funds. Upon occurrence of an
        Event of Default, Landlord may use all or any part of the Security
        Deposit to pay past due rent or other payments due Landlord under this
        Lease or the cost of any other damage, injury, expense or liability
        caused by such Event of Default, without prejudice to any other remedy
        provided herein or provided by law. On demand after application of any
        portion of the Security Deposit, Tenant shall pay Landlord the amount
        that will restore the Security Deposit to its original amount. The
        Security Deposit shall be deemed the property of Landlord, but any
        remaining balance of the Security Deposit shall be returned by
        Landlord to Tenant when all of Tenant's present and future obligations
        under this Lease have been fulfilled. If Landlord transfers its
        interest in the Building during the term of this Lease, Landlord shall
        assign any unforfeited portion of the Security Deposit to the
        transferee if the transferee executes and delivers a letter to Tenant
        acknowledging receipt of the Security Deposit and liability for the
        same, and expressly assumes all obligations of Landlord under this
        Lease.

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                (iv) REDUCTION OF LETTER OF CREDIT. The following shall be the
        conditions to a reduction in the amount of the Letter of Credit:

                (1)     If Tenant achieves four (4) consecutive increasingly
                        profitable quarters that reach an aggregate minimum net
                        profit of $2,500,000.00, based on generally accepted
                        accounting principles, consistently applied (the
                        "MINIMUM PERFORMANCE CRITERIA"), the Letter of Credit
                        may be reduced by $66,600.00;

                (2)     At such time thereafter as Tenant achieves a minimum
                        aggregate net profit of $2,500,000.00 during four (4)
                        consecutive quarters (not including any of the four
                        quarters used in paragraph 2B(iv)(1), above), based on
                        generally accepted accounting principles, consistently
                        applied, the Letter of Credit may be reduced by an
                        additional $66,600.00; and

                (3)     At such time thereafter as Tenant achieves a minimum
                        aggregate net profit of $2,500,000.00 during four (4)
                        consecutive quarters (not including any of the four
                        quarters used in paragraph 2B(iv)(2), above), based on
                        generally accepted accounting principles, consistently
                        applied, the Letter of Credit may be reduced by an
                        additional $66,600.00.

                (4)     The remainder of the Letter of Credit shall not be
                        subject to further reductions.

         C. ESCROW DEPOSITS. Without limiting in any way Tenant's other
obligations under this Lease, Tenant agrees to pay to Landlord its Proportionate
Share (as defined in this Paragraph 2C) of (i) Taxes (hereinafter defined)
payable by Landlord pursuant to Paragraph 3A, below, (ii) the cost of utilities
payable by Landlord pursuant to Paragraph 3, below, (iii) Landlord's cost of
maintaining insurance pursuant to Paragraph 9A, below, and (iv) Landlord's cost
of maintaining the Premises pursuant to paragraph 5C, below and any common area
charges payable by Tenant in accordance with Paragraph 4B, below (collectively,
the "TENANT COSTS"). During each month of the term of this Lease, on the same
day that rent is due hereunder, Tenant shall deposit in escrow with Landlord an
amount equal to one-twelfth (1/12) of the estimated amount of Tenant's
Proportionate Share of the Tenant Costs. Tenant authorizes Landlord to use the
funds deposited with Landlord under this Paragraph 2C to pay such Tenant Costs.
The initial monthly escrow payments are based upon the estimated amounts for the
year in question and shall be increased or decreased annually to reflect the
projected actual amounts of all Tenant Costs. If the Tenant's total escrow
deposits for any calendar year are less than Tenant's actual Proportionate Share
of the Tenant Costs for such calendar year, Tenant shall pay the difference to
Landlord within ten (10) days after demand. If the total escrow deposits of
Tenant for any calendar year are more than Tenant's actual Proportionate Share
of the Tenant Costs for such calendar year, Landlord shall retain such excess
and credit it against Tenant's escrow deposits next maturing after such
determination. Tenant's "PROPORTIONATE SHARE" with respect to the Building, as
used in this Lease, shall mean a fraction, the numerator of which is the gross
rentable area contained in the Premises and the denominator of which is the
gross rentable area contained in the entire Building. In the event the Premises
or the Building is part of a project or business park owned, managed or leased
by Landlord or an affiliate of Landlord (the "PROJECT"), Tenant's "PROPORTIONATE
SHARE" with respect to the Project, as used in this Lease, shall mean a
fraction, the numerator of which is the gross rentable area contained in the
Premises and the denominator of which is the gross rentable area contained in
all of the buildings (including the Building) within the Project.

3.      TAXES

        A. REAL PROPERTY TAXES. Subject to reimbursement under Paragraph 2C
herein, Landlord agrees to pay all taxes, assessments and governmental charges
of any kind and nature (collectively referred to herein as "TAXES") that accrue
against the Premises, the Building and/or the Property. If at any time during
the term of this Lease there shall be levied, assessed or imposed on Landlord a
capital levy or other tax directly on the rents received therefrom and/or a
franchise tax, assessment, levy or charge measured by or based, in whole or in
part, upon such rents from the Premises and/or the Property, the Building or any
other improvements of which the Premises are a part, then all such taxes,
assessments, levies or charges, or the part thereof so measured or based shall
be deemed to be included in the term "Taxes" for the purposes hereof. The
Landlord shall have the right to employ a tax-consulting firm to attempt to
assure a fair tax burden on the real property within the applicable taxing
jurisdiction. Tenant agrees to pay its Proportionate Share of the cost of such
consultant.

        B. PERSONAL PROPERTY TAXES. Tenant shall be liable for all taxes levied
or assessed against any personal property or fixtures placed in or on the
Premises. If any such taxes are levied or assessed against Landlord or
Landlord's property and (i) Landlord pays the same or (ii) the assessed value of
Landlord's property is increased by inclusion of such personal property and
fixtures and Landlord pays the increased taxes, then Tenant shall pay to
Landlord, upon demand, the amount of such taxes.

4.      LANDLORD'S REPAIRS AND MAINTENANCE.

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        A. STRUCTURAL REPAIRS. Landlord, at its own cost and expense, shall
maintain the roof, foundation and the structural soundness of the exterior
walls of the Building in good repair, reasonable wear and tear excluded. The
term "walls" as used herein shall not include windows, glass or plate glass,
any doors, special store fronts or office entries, and the term "foundation"
as used herein shall not include loading docks. Tenant shall immediately give
Landlord written notice of defect or need for repairs, after which Landlord
shall have reasonable opportunity to effect such repairs or cure such defect.

        B. TENANT'S SHARE OF COMMON AREA CHARGES. Tenant agrees to pay its
Proportionate Share of the cost of (i) maintenance and/or landscaping (including
both maintenance and replacement of landscaping) of any property that is a part
of the Building and/or the Project; (ii) operating, maintaining and repairing
any property, facilities or services (including without limitation utilities and
insurance therefor) provided for the use or benefit of Tenant or the common use
or benefit of Tenant and other lessees of the Project or the Building; and (iii)
an administrative fee of fifteen percent (15%) of all common area maintenance
charges.

5.      TENANT'S REPAIRS.

         A. MAINTENANCE OF PREMISES AND APPURTENANCES. Tenant, at its own
cost and expense, shall (i) maintain all parts of the Premises and promptly
make all necessary repairs and replacements to the Premises (except those for
which Landlord is expressly responsible hereunder), and (ii) keep the parking
areas, driveways and alleys surrounding the Premises in a clean and sanitary
condition. Tenant's obligation to maintain, repair and make replacements to
the Premises shall cover, but not be limited to, pest control, trash removal
and the maintenance, repair and replacement of all HVAC, electrical,
plumbing, sprinkler and other mechanical systems.

        B. SYSTEM MAINTENANCE. Tenant, at its own cost and expense, shall enter
into a regularly scheduled preventive maintenance/service contract with a
maintenance contractor approved by Landlord for servicing all hot water, heating
and air conditioning systems and equipment within the Premises. The service
contract must include all services suggested by the equipment manufacturer in
its operations/maintenance manual and must become effective within thirty (30)
days of the date Tenant takes possession of the Premises.

        C. OPTION TO MAINTAIN PREMISES. Landlord reserves the right to perform,
in whole or in part and without notice to Tenant, maintenance, repairs and
replacements to the Premises, paving, common area, landscape, exterior painting,
common sewage line plumbing and any other items that are otherwise Tenant's
obligations under this Section 5, in which event, Tenant shall be liable for its
Proportionate Share of the cost and expense of such repair, replacement,
maintenance and other such items.

6.      ALTERATIONS.

Tenant shall not make any alterations, additions or improvements to the premises
without the prior written consent of Landlord. Tenant at its own cost and
expense, may erect such shelves, bins, furniture, machinery, liquid nitrogen
piping and associated equipment (including a tank and compressor outside the
Building), alternate fire suppression system and other trade fixtures as it
desires, provided that (i) such items do not alter the basic character of the
Premises or the Building, (ii) such items do not overload or damage the Building
or any Building systems, (iii) such items may be removed without injury to the
Premises, and (iv) the construction, erection or installation thereof complies
with all applicable governmental laws, ordinances, regulations and with
Landlord's specifications and requirements. Tenant shall be responsible for the
compliance of all of its alterations, additions and improvements to the Premises
with the Americans With Disabilities Act of 1990 and the Texas Architectural
Barriers Act. Except for removable furniture, fixtures and equipment, raised
computer floor(s), cubical furniture, liquid nitrogen piping and associated
equipment (including outside tank and compressor), alternate fire suppression
system and de-mountable interior wall panels, all alterations, additions,
improvements and partitions erected by Tenant shall be and remain the property
of Landlord immediately upon installation. All shelves, bins, furniture,
machinery, liquid nitrogen piping and associated equipment (including exterior
tank and compressor), raised computer floor(s), cubical furniture, alternate
fire suppression system(s) and removable trade fixtures installed by Tenant
shall be the Property of Tenant and shall be removed by Tenant on or before the
earlier to occur of the day of termination or expiration of this Lease or
vacating the Premises, at which time Tenant shall restore the Premises to the
condition which existed as of the completion of the Interior Improvements
[specifically excluding liquid nitrogen piping and associated equipment
(including exterior tank and compressor) and alternate fire suppression
system(s)], reasonable wear and tear excepted. All alterations, installations,
removals and restorations shall be performed in a good and workmanlike manner so
as not to damage or alter the primary structure or structural qualities of the
Building or other improvements situated on the Premises or of which the Premises
are a part.

7.      SIGNS.

Any signage Tenant desires shall be subject to Landlord's written approval and
shall be submitted to Landlord prior to installation. Tenant shall repair, paint
and/or replace the Building fascia surface to which its signs are attached upon
Tenant's vacating the Premises or the removal or alteration of its signage.
Tenant shall not, without Landlord's

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prior written consent, (i) make any changes to the exterior of the Building or
the Premises, such as painting; (ii) install any exterior lights, decorations,
balloons, flags, pennants or banners; or (iii) erect or install any signs,
windows or door lettering, placards, decorations or advertising media of any
type which can be viewed from the exterior of the Premises. All signs,
decorations, advertising media, blinds, draperies and other window treatment or
bars or other security installations visible from outside the Premises shall
conform in all respects to the criteria established by Landlord or shall be
otherwise subject to Landlord's prior written consent.

8.      UTILITIES.

Landlord agrees to provide water, electricity and wastewater service to the
Premises. Electrical service to the Building shall be at least three phase, 480
volt, 1,000 amperes, 20 watts per square foot. Tenant shall pay for all water,
gas, heat, light, power, telephone, sewer, sprinkler charges and other utilities
and services used on or at the Premises, together with any taxes, penalties,
surcharges or the like pertaining to the Tenant's use of the Premises and any
maintenance charges for utilities. Landlord shall have the right to cause any of
said services to be separately metered to Tenant, at Tenant's expense. Tenant
shall pay its prorata share, as reasonably determined by Landlord, of all
charges for jointly metered utilities. Landlord shall not be liable for any
interruption or failure of utility service on the Premises, and Tenant shall
have no rights or claims as a result of any such failure, however, Landlord will
use its diligent good faith efforts to restore any such failure of utility
service as soon as reasonably practicable. In the event water is not separately
metered to Tenant, Tenant agrees that it will not use the water and sewer
capacity for uses other than normal domestic restroom and kitchen usage, and
Tenant further agrees to reimburse Landlord for the entire amount of common
water and sewer costs as additional rental if, in fact, Tenant uses water or
sewer capacity for uses other than normal domestic restroom and kitchen uses
without first obtaining Landlord's written permission, including but not limited
to the cost for acquiring additional sewer capacity to service Tenant's excess
sewer use. Furthermore, Tenant agrees in such event to install its own expense a
submeter to determine Tenant's usage.

9.      INSURANCE.

        A. LANDLORD'S INSURANCE. Subject to reimbursement under Paragraph 2C
herein, Landlord shall maintain insurance covering the Building in an amount not
less than eighty percent (80%) of the "replacement cost" thereof, insuring
against the perils of fire, lightning, extended coverage, vandalism and
malicious mischief. Landlord, at Landlord's election, may carry insurance in
such additional amounts and coverages as Landlord may deem prudent from time to
time and the cost of such additional insurance shall likewise be reimbursable
under Paragraph 2C hereof.

        B. TENANT'S INSURANCE. Tenant, at its own expense, shall maintain during
the term of this lease a policy or policies of worker's compensation and
comprehensive general liability insurance, including personal injury and
property damage, with contractual liability endorsement, in the amount of Five
Hundred Thousand Dollars ($500,000.00) for property damage and One Million
Dollars ($ 1,000,000.00) per occurrence and One Million Dollars ($1,000,000.00)
in the aggregate for personal injuries or deaths of persons occurring in or
about the Premises. Tenant, at its own expense, shall also maintain during the
term of this Lease fire and extended coverage insurance covering the replacement
cost of (i) all alterations, additions, partitions and improvements installed or
placed on the Premises by Tenant or by Landlord on behalf of Tenant; and (ii)
Tenant's personal property contained within the Premises. Said policies shall
(i) name the Landlord as an additional insured and insure Landlord's contingent
liability under or in connection with this Lease (except for worker's
compensation policy, which instead shall include a waiver of subrogation
endorsement in favor of Landlord); (ii) be issued by an insurance company which
is acceptable to Landlord; and (iii) provide that said insurance shall not be
canceled unless thirty (30) days prior written notice has been given to
Landlord. Said policy or policies or certificates thereof shall be delivered to
Landlord by Tenant on or before the Commencement Date and upon each renewal of
said insurance.

        C. PROHIBITED USES. Tenant will not permit the Premises to be used for
any purpose or in any manner that would (i) void the insurance thereon, (ii)
increase the insurance risk or cost thereof, or (iii) cause the disallowance of
any sprinkler credits; including without limitation, use of the Premises for the
receipt, storage or handling of any product, material or merchandise that is
explosive or highly inflammable. If any increase in the cost of any insurance on
the Premises or the Building is caused by Tenant's use of the Premises or
because Tenant vacates the Premises, then Tenant shall pay the amount of such
increase to Landlord upon demand therefor.

10.     FIRE AND CASUALTY DAMAGE.

        A. TOTAL OR SUBSTANTIAL DAMAGE AND DESTRUCTION. If the Premises or the
Building should be damaged or destroyed by fire or other peril, Tenant shall
immediately give written notice to Landlord of such damage or destruction. If
the Premises or the Building should be totally destroyed by any peril covered by
the insurance to be provided by Landlord under Paragraph 9A above, or if they
should be so damaged thereby that, in Landlord's estimation, rebuilding or
repairs cannot be completed within one hundred eighty (180) days after the date
of such damage or after such completion there would not be enough time remaining
under the terms of this Lease to fully

                                                       Initial NSS [ILLEGIBLE]
                                                       Date  6/25/98  6/26/98

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amortize such rebuilding or repairs, then this Lease shall terminate and the
rent shall be abated during the unexpired portion of this lease, effective upon
the date of the occurrence of such damage.

        B. PARTIAL DAMAGE OR DESTRUCTION. If the Premises or the Building should
be damaged by any peril covered by the insurance to be provided by Landlord
under Paragraph 9A above and, in Landlord's estimation, rebuilding or repairs
can be substantially completed within one hundred eighty (180) days after the
date of such damage, then this Lease shall not terminate and Landlord shall
substantially restore the Premises to its previous condition, except that
Landlord shall not be required to rebuild, repair or replace any part of the
partitions, fixtures, additions and other improvements that may have been
constructed, erected or installed in or about the Premises for the benefit of,
by or for Tenant.

        C. LIENHOLDERS' RIGHTS IN PROCEEDS. Notwithstanding anything herein to
the contrary, in the event the holder of any indebtedness secured by a mortgage
or deed of trust covering the Premises requires that the insurance proceeds be
applied to such indebtedness, then Landlord shall have the right to terminate
this Lease by delivering written notice of termination to Tenant within fifteen
(15) days after such requirement is made known to Landlord by any such holder,
whereupon all rights and obligations hereunder shall cease and terminate.

        D. WAIVER OF SUBROGATION. Notwithstanding anything in this lease to the
contrary, Landlord and Tenant hereby waive and release each other of and from
any and all rights of recovery, claims, actions or causes of action against each
other, or their respective agents, officers and employees, for any loss or
damage that may occur to the Premises, improvements to the Building or personal
property (Building contents) within the Building and/or Premises, for any reason
regardless of cause or origin. Each party to this Lease agrees immediately after
execution of this Lease to give written notice of the terms of the mutual
waivers contained in this subparagraph to each insurance company that has issued
to such party policies of fire and extended coverage insurance and to have the
insurance policies properly endorsed to provide that the carriers of such
policies waive all rights of recovery under subrogation or otherwise against the
other party.

11.     LIABILITY AND INDEMNIFICATION.

Except for any claims, rights of recovery and causes of action that Landlord has
released, Tenant shall hold Landlord harmless from and defend Landlord against
any and all claims or liability for any injury or damage (i) to any person or
property whatsoever occurring in, on or about the Premises or any part thereof,
the Building and/or other common areas, the use of which Tenant may have in
accordance with this Lease, if (and only if) such injury or damage shall be
caused in whole or in part by the act, neglect, fault or omission of any duty by
Tenant, its agents, servants, employees or invitees; (ii) arising from the
conduct or management of any work done by the Tenant in or about the Premises;
(iii) arising from transactions of the Tenant; and (iv) all costs, counsel fees,
expenses and liabilities incurred in connection with any such claim or action or
proceeding brought thereon. The provisions of this Paragraph 11 shall survive
the expiration or termination of this Lease. Landlord shall not be liable in any
event for personal injury or loss of Tenant's property caused by fire, flood,
water leaks, rain, hail, ice, snow, smoke, lightning, wind, explosion,
interruption of utilities or other occurrences. LANDLORD STRONGLY RECOMMENDS
THAT TENANT SECURE TENANT'S OWN INSURANCE IN EXCESS OF THE AMOUNTS REQUIRED
ELSEWHERE IN THIS LEASE TO PROTECT AGAINST THE ABOVE OCCURRENCES IF TENANT
DESIRES ADDITIONAL COVERAGE FOR SUCH RISKS. Tenant shall give prompt notice to
Landlord of any significant accidents involving injury to persons or property.
Furthermore, Landlord shall not be responsible for lost or stolen personal
property, equipment, money or jewelry from the Premises or from the public areas
of the Building or the Project, regardless of whether such loss occurs when the
area is locked against entry. Landlord shall not be liable to Tenant or Tenant's
employees, customers or invitees for any damages or losses to persons or
property caused by any lessees in the Building or the Project and/or any
personal injury or property damage caused thereby. Landlord may, but is not
obligated to, enter into agreements with third parties for the provision,
monitoring, maintenance and repair of any courtesy patrols or similar services
or fire protective systems and equipment and, to the extent same is provided at
Landlord's sole discretion, Landlord shall not be liable to Tenant for any
damages, costs or expenses which occur for any reason in the event any such
system or equipment is not properly installed, monitored or maintained or any
such services are not property provided. Landlord shall use reasonable diligence
in the maintenance of lighting furnished by Landlord, if any, in the parking
garage or parking areas servicing the Premises, and Landlord shall not be
responsible for additional lighting or any security measures in the Project, the
Premises, the parking garage or other parking areas.

12.     USE.

Subject to the other provisions of this Lease, Tenant may use the Premises
for the purpose of conducting a manufacturing and testing services facility
as permitted under the IP-CO zoning of the Property, together with attendant
office areas and dining amenities, and for such other purposes as are
permitted by the applicable zoning restrictions of the Property. Outside
storage, including without limitation storage of trucks and other vehicles,
is prohibited without Landlord's prior written consent. Tenant shall comply
with all governmental laws, ordinances and regulations applicable to the use
of the Premises and shall promptly comply with all governmental orders and

                                                       Initial NSS [ILLEGIBLE]
                                                       Date  6/25/98  6/26/98

                                       6
<PAGE>

directives for the correction, prevention and abatement of nuisances in, upon
or connected with the Premises, all at Tenant's sole expense. Tenant shall not
permit any objectionable or unpleasant odors, smoke, dust, gas, noise or
vibrations to emanate from the Premises, nor take any other action that would
constitute a nuisance or would disturb, unreasonably interfere with or endanger
Landlord or the tenants of other buildings in the vicinity of the Building or
the Project.

13. HAZARDOUS SUBSTANCES.

        A. REGULATION OF HAZARDOUS SUBSTANCES AND INDEMNITY. The term "HAZARDOUS
SUBSTANCES", as used in this Lease, shall mean pollutants, contaminants, toxic
or hazardous substances, substances that are reactive, corrosive or ignitable,
radioactive materials, asbestos, polychlorobiphenyls, petroleum and petroleum
distillates and any other substances, the use and/or the removal of which is
required or the use of which is restricted, prohibited or penalized by any
"Environmental Law", which term shall mean any federal, state or local statute,
ordinance, regulation or other law of a governmental or quasi-governmental
authority relating to pollution or protection of the environment or the
regulation of the storage or handling of Hazardous Substances. Tenant hereby
agrees that: (i) no activity will be conducted on the Premises that will produce
any Hazardous Substances, except for such activities that are part of the
ordinary course of Tenant's business activities (the "PERMITTED ACTIVITIES"),
provided said Permitted Activities are conducted in accordance with all
Environmental laws and have been approved in advance in writing by Landlord and,
in connection therewith, Tenant shall be responsible for obtaining any required
permits or authorizations and paying any fees and providing any testing required
by any governmental agency; (ii) the Premises will not be used in any manner for
the storage of any Hazardous Substances, except for the temporary storage of
such materials that are used in the ordinary course of Tenant's business (the
"PERMITTED MATERIALS"), provided such Permitted Materials are properly stored in
a manner and location meeting all Environmental Laws and have been approved in
advance in writing by Landlord, and, in connection therewith, Tenant shall be
responsible for obtaining any required permits or authorizations and paying any
fees and providing any testing required by any governmental agency; (iii) no
portion of the Premises will be used as a landfill or a dump; (iv) Tenant will
not install any underground tanks of any type; (v) Tenant will not allow any
surface or subsurface conditions to exist or come into existence that
constitute, or with the passage of any time may constitute, a public or private
nuisance; and (vi) Tenant will not permit any Hazardous Substances to be brought
onto the Premises, except for the Permitted Materials, and if so brought or
found located thereon, the same shall be immediately removed, with proper
disposal, and all required clean-up procedures shall be diligently undertaken by
Tenant at its sole cost pursuant to all Environmental Laws. Landlord and
Landlord's representatives shall have the right but not the obligation to enter
the Premises for the purpose of inspecting the storage, use and disposal of any
Permitted Materials to ensure compliance with all Environmental Laws. Should it
be determined, in Landlord's sole opinion, that any Permitted Materials are
being improperly stored, used or disposed of, or that any non-Permitted
Materials are present on the Premises, then Tenant shall immediately take such
corrective action as requested be Landlord. Should Tenant fail to take such
corrective action within twenty four (24) hours, Landlord shall have the right
to perform such work and Tenant shall reimburse Landlord, on demand, for any and
all costs associated with said work. Tenant shall indemnify, defend and hold
Landlord harmless from any and all claims, damages, fines, judgments, penalties,
costs, liabilities, or losses (including, without limitation, a decrease in
value of the Project, damages caused by loss or restriction of rentable or
usable space, or any damages caused by adverse impact on marketing of the space,
and any and all sums paid for settlement of claims, attorneys' fees, consultant
and expert fees) arising during or after the Term hereof and arising as a result
of any contamination, Hazardous Substance release or spill by Tenant. This
indemnification includes, without limitation, any and all costs incurred because
of any investigation of the site or any cleanup, removal, or restoration
mandated by a federal, state, or local agency or political subdivision. Without
limitation of the foregoing, if Tenant causes or permits the presence of any
Hazardous Substance on the Project, including, without limitation, any Permitted
Materials, by any of its agents, employees, guests, invitees, contractors,
subcontractors or subtenants which results in contamination, Tenant shall
promptly, at its sole expense, take any and all necessary actions to return the
Project to the condition existing prior to the presence of any such Hazardous
Substance on the Project. Tenant shall first obtain Landlord's approval for any
such remedial action. The foregoing indemnification and the responsibilities of
Tenant shall survive the termination or expiration of this Lease.

         B. LANDLORD'S REPRESENTATIONS AND OBLIGATIONS. Landlord hereby
represents and warrants to Tenant that, to Landlord's current actual knowledge,
and based solely upon that certain Environmental Site Assessment Report, dated
June 25, 1998, as of the date hereof there are no Hazardous Substances present
or stored on, in or about the Project and there is no Hazardous Substance
contamination on the Project or any portion thereof. Landlord shall not cause or
permit any Hazardous Substance to be used, stored, generated, or disposed of on
or in the Project by Landlord or Landlord's agents, employees, guests, invitees,
contractors, or subcontractors. If Hazardous Substances are used, stored,
generated or disposed of by Landlord or Landlord's agents, employees, guests,
invitees, contractors, or subcontractors (specifically excluding Tenant and
Tenant's agents, employees, guests, invitees, contractors, or subcontractors) on
or in the Project, or if the Project becomes contaminated in any way by Landlord
or Landlord's agents, employees, guests, invitees, contractors, or
subcontractors (specifically excluding Tenant and Tenant's agents, employees,
guests, invitees, contractors, or subcontractors), Landlord shall indemnify,
defend and hold Tenant harmless from any and all claims, damages, fines,
judgments, penalties, costs, liabilities, or losses (including, without
limitation, and any and all sums paid for settlement of claims, attorneys' fees,
consultant

                                                       Initial NSS [ILLEGIBLE]
                                                       Date  6/25/98  6/26/98

                                       7
<PAGE>

and expert fees) arising during or after the Term hereof and arising as a result
of Hazardous Substance contamination caused by the use, storage, generation, or
disposal of Hazardous Substances on or in the Project by Landlord or Landlord's
agents, employees, guests, invitees, contractors, or subcontractors
(specifically excluding Tenant and Tenant's agents, guests, invitees,
contractors, or subcontractors). This indemnification includes, without
limitation, any and all costs incurred because of any investigation of the site
or any cleanup, removal, or restoration mandated by a federal, state, or local
agency or political subdivision. The foregoing indemnification and the
responsibilities of Landlord shall survive the termination or expiration of this
Lease.

        C. DEFINITION OF "HAZARDOUS SUBSTANCE". As used herein, "Hazardous
Substance" means any substance that is toxic, ignitable, reactive, or
corrosive and that is regulated by any local government, the state of Texas,
or the United States Government. "Hazardous Substance" includes any and all
material or substances that are defined as "hazardous waste," "extremely
hazardous waste," or a "hazardous substance" pursuant to state, federal, or
local government law. "Hazardous Substance" includes but is not restricted to
asbestos, polychlorobiphenyls, petroleum and petroleum distillates.

14.     ARCHITECTURAL BARRIERS

        A. LANDLORD'S OBLIGATIONS. Landlord hereby agrees to design and
construct the base building and exterior portions of the Project (but
specifically excluding the design or the Interior Improvements and any other
Tenant Alterations) in compliance with the requirements of the Americans with
Disabilities Act (the "ADA") and the Texas Architectural Barriers Act (the
"TABA"). Landlord will indemnify and hold Tenant harmless from any and all
claims, actions, causes of action, liability, loss, cost or expense, including
court costs and attorneys fees, incurred by Tenant as a result of claims by
third parties (including the federal government or the State of Texas but
excluding any claims of Tenant or any subtenants of Tenant) based on the failure
of the failure of the base building and exterior portions of the Project (but
specifically excluding the design or the Premises) to comply with the ADA or the
TABA.

        B. TENANT'S OBLIGATIONS. Tenant hereby agrees to design the Interior
Improvements and all other Alterations by or for Tenant in compliance with the
requirements of the ADA and the TABA. Tenant will indemnify and hold Landlord
harmless from any and all claims, actions, causes of action, liability, loss,
cost or expense, including court costs and attorneys fees, incurred by Landlord
as a result of claims by third parties (including the federal government or the
State of Texas) based on the failure of the Premises (but specifically excluding
the base building and exterior portions of the Project designed and constructed
by Landlord) to comply with the ADA or the TABA.

15.     INSPECTION.

Landlord's agents and representatives shall have the right to enter the Premises
at any reasonable time during business hours (or at any time in case of
emergency) (i) to inspect the Premises, (ii) to make such repairs as may be
required or permitted pursuant to this Lease, and/or (iii) during the last six
(6) months of the Lease term, for the purpose of showing the Premises. In
addition, Landlord shall have the right to erect a suitable sign on the Premises
stating the Premises are available for lease. Tenant shall notify Landlord in
writing at least thirty (30) days prior to vacating the Premises and shall
arrange to meet with Landlord for a joint inspection of the Premises prior to
vacating. If Tenant fails to give such notice or to arrange for such inspection,
then Landlord's inspection of the Premises shall be deemed correct for the
purpose of determining Tenant's responsibility for repairs and restoration of
the Premises.

16.     ASSIGNMENT AND SUBLETTING.

Tenant shall not have the right to sublet, assign or otherwise transfer or
encumber this Lease, or any interest therein, without the prior written consent
of Landlord, which consent will not be unreasonably withheld so long as (i) the
creditworthiness and financial condition of the proposed assignee or sublessee
is satisfactory to Landlord, in Landlord's reasonable discretion, and (ii) the
proposed use of the Premises by such proposed assignee or sublessee would not,
in Landlord's reasonable opinion, be detrimental to the Building, the Project or
the other tenants therein. Any attempted assignment, subletting, transfer or
encumbrance by Tenant in violation of the terms and covenants of this paragraph
shall be void. Any assignee, sublessee or transferee of Tenant's interest in
this Lease (all such assignees, sublessees and transferees being hereinafter
referred to as "TRANSFEREES"), by assuming Tenant's obligations hereunder, shall
assume liability to Landlord for all amounts paid to persons other than Landlord
by such Transferees to which Landlord is entitled or is otherwise in
contravention of this Paragraph 15. No assignment, subletting or other transfer,
whether or not consented to by Landlord or permitted hereunder, shall relieve
Tenant of its liability under this Lease. If an Event of Default occurs while
the Premises or any part thereof are assigned or sublet, then Landlord, in
addition to any other remedies herein provided or provided by law, may collect
directly from such Transferee all rents payable to the Tenant and apply such
rent against any sums due Landlord hereunder. No such collection shall be
construed to constitute a novation or a release of Tenant from the further
performance of Tenant's obligations and liabilities hereunder. If Landlord
consents to any subletting or assignment by Tenant as hereinabove provided and
any category of rent subsequently received by Tenant under any such sublease is
in excess of the same

                                                       Initial NSS [ILLEGIBLE]
                                                       Date  6/25/98  6/26/98

                                       8
<PAGE>

category of rent payable under this Lease, or any additional consideration is
paid to Tenant by the assignee under any such assignment, then Landlord may, at
its option, declare such excess rents under any sublease or such additional
consideration for any assignment to be due and payable by Tenant to Landlord as
additional rent hereunder. The following shall additionally constitute an
assignment of this Lease by Tenant for the purposes of this Paragraph 15: (i) if
Tenant is a corporation, any merger, consolidation, dissolution or liquidation,
or any change in ownership or owner entitled to vote thirty percent (30%) or
more of Tenant's outstanding voting stock other than pursuant to (A) a
registered public offering of Tenant's stock, (B) a sale of stock or a merger
with another company whose stock is listed on a recognized exchange, or (C) a
joint venture between Tenant and a third party; (ii) if Tenant is a partnership,
joint venture or other entity, any liquidation, dissolution or transfer of
ownership of any interests totaling thirty percent (30%) or more of the total
interests in such entity; (iii) the sale, transfer, exchange, liquidation or
other distribution of more than thirty percent (30%) of Tenant's assets, other
than this Lease; or (iv) the mortgage, pledge, hypothecation or other
encumbrance of or grant of a security interest by Tenant in this Lease, or any
of Tenant's rights hereunder.

17.     CONDEMNATION.

If more than eighty percent (80%) of the Premises are taken for any public or
quasi-public use under governmental law, ordinance or regulation, or by right of
eminent domain or private purchase in lieu thereof, and the taking prevents or
materially interferes with the use of the remainder of the Premises for the
purpose for which they were leased to Tenant, then this Lease shall terminate
and the rent shall be abated for the unexpired portion of this Lease, effective
on the date of such taking. If less than eighty percent (80%) of the Premises
are taken for any public or quasi-public use under any governmental law,
ordinance or regulation, or by right of eminent domain or private purchase in
lieu thereof, or if the taking does not prevent or materially interfere with the
use of the remainder of the Premises for the purpose for which they were leased
to Tenant, then this Lease shall not terminate, but the rent payable hereunder
during the unexpired portion of this Lease shall be reduced to such extent as
may be fair and reasonable under all circumstances. All compensation awarded in
connection with or as a result of any of the foregoing proceedings shall be the
property of Landlord, and Tenant hereby assigns any interest in any such award
to Landlord; provided, however, Landlord shall have no interest in any award
made to Tenant for Tenant's moving expenses or for the taking of Tenant's trade
fixtures and personal property, if a separate award for such items is made to
Tenant. Notwithstanding the foregoing, Tenant may pursue a separate award in
condemnation, at its own expense, so long such award does not operate to reduce
the award paid to Landlord.

18.     HOLDING OVER.

At the termination of this Lease by its expiration or otherwise, Tenant shall
immediately deliver possession of the Premises to Landlord with all repairs and
maintenance required herein to be performed by Tenant completed. If for any
reason Tenant retains possession of the Premises after the expiration or
termination of this Lease, unless the parties hereto otherwise agree in writing,
such possession shall be deemed to be a tenancy at will only, and all of the
other terms and provisions of this Lease shall be applicable during such period,
except that Tenant shall pay Landlord from time to time, upon demand, as rental
for the period of such possession, an amount equal to one and one-half (1-1/2)
times the rent in effect on the date of such termination of this lease, computed
on a daily basis for each day of such period. No holding over by Tenant, whether
with or without consent of Landlord, shall operate to extend this Lease except
as otherwise expressly provided. The preceding provisions of this Paragraph 18
shall not be construed as consent for Tenant to retain possession of the
Premises in the absence of written consent thereto by Landlord.

19.     QUIET ENJOYMENT.

Landlord represents that it has the authority to enter into this lease and that,
so long as Tenant pays all amounts due hereunder and performs all other
covenants and agreements herein set forth, Tenant shall peaceably and quietly
have, hold and enjoy the Premises for the term hereof without hindrance or
molestation from Landlord, subject to the terms and provisions of this Lease.

20.     EVENTS OF DEFAULT.

The following events (herein individually referred to as an "EVENT OF DEFAULT")
each shall be deemed to be a default in or breach of Tenant's obligations under
this Lease:

        A. Tenant shall fail to pay any installment of the rent herein reserved
when due, or any other payment or reimbursement to Landlord required herein when
due, and such failure shall continue for a period of ten (10) days from the date
such payment was due. Notwithstanding the foregoing, Tenant shall be entitled to
written notice from Landlord not more than two times during any twelve (12)
consecutive month period that Tenant has failed to timely pay any rent or
additional rent hereunder before such failure shall constitute an Event of
Default. Unless Landlord receives such payment within ten (10) days after such
written notice, Tenant's failure shall constitute an Event of Default.

                                                       Initial NSS [ILLEGIBLE]
                                                       Date  6/25/98  6/26/98

                                       9
<PAGE>

        B. Tenant shall (i) vacate or abandon all or a substantial portion of
the Premises or (ii) fail to continuously operate its business at the Premises
for the permitted use set forth herein, in either event whether or not Tenant is
in default of the rental payments due under this lease.

        C. Tenant shall fail to discharge any lien placed upon the Premises in
violation of Paragraph 23 hereof within twenty (20) days after such lien or
encumbrance is filed against the Premises.

        D. Tenant shall default in the performance of any of its obligations
under any other lease to Tenant from Landlord, or from any person or entity
affiliated with or related to Landlord, including, without limitation, the
Office Building Owner (as defined in EXHIBIT "E" attached hereto) and same shall
remain uncured after the lapsing of any applicable cure periods provided for
under such other lease.

        E. Tenant shall fail to comply with any term, provision or covenant of
this Lease (other than those listed above in this paragraph) and shall not cure
such failure within thirty (30) days after written notice thereof from Landlord.

21.     REMEDIES.

Upon each occurrence of an Event of Default, Landlord shall have the option to
pursue any one or more of the following remedies without any notice or demand:

        (a) Terminate this Lease;

        (b) Enter upon and take possession of the Premises without terminating
this Lease;

        (c) Make such payments and/or take such action and pay and/or perform
whatever Tenant is obligated to pay or perform under the terms of this Lease,
and Tenant agrees that Landlord shall not be liable for any damages resulting to
Tenant from such action; and/or

        (d) Alter all locks and other security devices at the Premises, with or
without terminating this Lease, and pursue, at Landlord's option, one or more
remedies pursuant to this Lease, and Tenant hereby expressly agrees that
Landlord shall not be required to provide to Tenant the new key to the Premises,
regardless of hour, including Tenant's regular business hours;

and in any such event Tenant shall immediately vacate the Premises, and if
Tenant fails to do so, Landlord, without waiving any other remedy it may have,
may enter upon and take possession of the Premises and expel or remove Tenant
and any other person who may be occupying such Premises or any part thereof,
without being liable for prosecution or any claim of damages therefore. In the
event of any violation of Section 93.002 of the Texas Property Code by Landlord
or by any agent or employee of Landlord, Tenant hereby expressly waives any and
all rights Tenant may have under Paragraph (g) of such Section 93.002.

        A. DAMAGES UPON TERMINATION. If Landlord terminates this Lease at
Landlord's option, Tenant shall be liable for and shall pay to Landlord the sum
of all rental and other payments owed to Landlord hereunder accrued to the date
of such termination, plus, as liquidated damages, an amount equal to (i) the
present value of the total rental and other payments owed hereunder for the
remaining portion of the Lease term, calculated as if such term expired on the
date set forth in Paragraph 1, less (ii) the present value of the then fair
market rental for the Premises for such period, provided that, because of the
difficulty of ascertaining such value and in order to achieve a reasonable
estimate of liquidated damages hereunder, Landlord and Tenant stipulate and
agree, for the purposes hereof, that such fair market rental shall in no event
exceed seventy five percent (75%) of the rental amount for such period set forth
in Paragraph 2A above.

        B. DAMAGES UPON REPOSSESSION. If Landlord repossesses the Premises
without terminating this Lease, Tenant at Landlord's option, shall be liable for
and shall pay Landlord on demand all rental and other payments owed to Landlord
hereunder, accrued to the date of such repossession, plus all amounts require to
be paid by Tenant to Landlord until the date of expiration of the term as stated
in Paragraph 1, diminished by all amounts actually received by Landlord through
reletting the premises during such remaining term (but only to the extent of the
rent herein reserved). Actions to collect amounts due by Tenant to Landlord
under this paragraph may be brought from time to time, on one or more occasions,
without the necessity of Landlord's waiting until the expiration of the lease
term.

        C. COSTS OF RELETTING, REMOVING, REPAIRS AND ENFORCEMENT. Upon an
Event of Default, in addition to any sum provided to be paid under this
Paragraph 21, Tenant also shall be liable for and shall pay to Landlord (i)
broker's fees and all other costs and expenses incurred by Landlord in
connection with reletting the whole or any part of the Premises; (ii) the
costs of removing, storing or disposing of Tenant's or any other occupant's
property; (iii) the costs of repairing, altering, remodeling or otherwise
putting the Premises into condition acceptable to a new tenant or tenants;
(iv) any and all costs and expenses incurred by Landlord in effecting
compliance with Tenant's

                                       10
<PAGE>

obligations under this Lease; and (v) all reasonable expenses incurred by
Landlord in enforcing or defending Landlord's rights and/or remedies hereunder,
including without limitation all reasonable attorneys' fees and all court costs
incurred in connection with such enforcement or defense.

        D. LATE CHARGE. In the event Tenant fails to make any payment due
hereunder within five (5) days after such payment is due, including without
limitation any rental or escrow payment, in order to help defray the
additional cost to Landlord for processing such late payments and not as
interest, Tenant shall pay to Landlord on demand a late charge in an amount
equal to five percent (5%) of such payment. The provision for such late
charge shall be in addition to all of Landlord's other rights and remedies
hereunder or at law, and shall not be construed as liquidated damages or as
limiting Landlord's remedies in any manner.

        E. INTEREST ON PAST DUE AMOUNTS. If Tenant fails to pay any sum which
at any time becomes due to Landlord under any provision of this Lease as and
when the same becomes due hereunder, and such failure continues for ten (10)
days after the due date for such payment, then Tenant shall pay to Landlord
interest on such overdue amounts from the date due until paid at an annual
rate which equals the lesser of (i) eighteen percent (18%) or (ii) the
highest rate then permitted by law.

        F. NO IMPLIED ACCEPTANCES OR WAIVERS. Exercise by Landlord of any one
or more remedies hereunder granted or otherwise available shall not be deemed
to be an acceptance by Landlord of Tenant's surrender of the Premises, it
being understood that such surrender can be effected only by the written
agreement of Landlord. Tenant and Landlord further agree that forbearance by
Landlord to enforce any of its rights under this lease or at law or in equity
shall not be a waiver of Landlord's right to enforce any one or more of its
rights, including any right previously forborne, in connection with any
existing or subsequent default. No re-entry or taking possession of the
Premises by Landlord shall be construed as an election on its part to
terminate this Lease, unless a written notice of such intention is given to
Tenant, and, notwithstanding any such reletting or re-entry or taking
possession of the Premises, Landlord may at any time thereafter elect to
terminate this lease for a previous default. Pursuit of any remedies
hereunder shall not preclude the pursuit of any other remedy herein provided
or any other remedies provided by law, nor shall pursuit of any remedy herein
provided constitute a forfeiture or waiver of any rent due to Landlord
hereunder or of any damages occurring to Landlord by reason of the violation
of any of the terms, provisions and covenants contained in this Lease.
Landlord's acceptance of any rent following an Event of Default hereunder
shall not be construed as Landlord's waiver of such Event of Default. No
waiver by Landlord of any violation or breach of any of the terms, provisions
and covenants of this lease shall be deemed or construed to constitute a
waiver of any other violation or default.

        G. RELETTING OF PREMISES. In the event of any termination of this
Lease and/or repossession of the Premises for an Event of Default, Landlord
shall use reasonable efforts to relet the Premises and to collect rental
after reletting, with no obligation to accept any lessee that Landlord deems
undesirable, to expend any funds in connection with such reletting or
collection of rents therefrom, or to lease the Premises in preference to any
other space that Landlord may have available for lease at the time. Tenant
shall not be entitled to credit for or reimbursement of any proceeds of such
reletting in excess of the rental owed hereunder for the period of such
reletting. Landlord may relet the whole or any portion of the Premises, for
any period, to any tenant and for any use or purpose.

        H. LANDLORD'S DEFAULT. If Landlord fails to perform any of its
obligations hereunder within thirty (30) days after written notice from
Tenant specifying such failure, Tenant's exclusive remedy shall be an action
for damages. Unless and until Landlord fails to so cure any default after
such notice, Tenant shall not have any remedy or cause of action by reason
thereof. All obligations of Landlord hereunder will construed as covenants,
not conditions; and all such obligations will be binding upon Landlord only
during the period of its possession of the premises and not thereafter. The
term "LANDLORD" shall mean only the owner, for the time being, of the
Premises and, in the event of the transfer by such owner of its interest in
the Premises, such owner shall thereupon be released and discharged from all
covenants and obligations of the Landlord thereafter accruing, provided that
such covenants and obligations shall be binding during the lease term upon
each new owner for the duration of such owner's ownership. Notwithstanding
any other provision of this Lease, Landlord shall not have any personal
liability hereunder. In the event of any breach or default by Landlord in any
term or provision of this Lease, Tenant agrees to look solely to the equity
or interest then owned by Landlord in the Premises or the Building; however,
in no event shall any deficiency judgment or any money judgment of any kind
be sought or obtained against any Landlord.

        I. TENANT'S PERSONAL PROPERTY. If Landlord repossesses the Premises
pursuant to the authority herein granted, or if Tenant vacates or abandons
all or any part of the Premises, then Landlord shall have the right to (i)
keep in place and use, or (ii) remove and store, all of the furniture,
fixtures and equipment at the Premises, including that which is owned by or
leased to Tenant, at all times prior to any foreclosure thereon by Landlord
or repossession thereof by any lessor thereof or third party having a lien
thereon. In addition to the Landlord's other rights hereunder, Landlord may
dispose of the stored property if Tenant does not claim the property within
ten (10) days after the date the property is stored. Landlord shall give
Tenant at least ten (10) days prior written notice of such intended
disposition. Landlord shall also have the right to relinquish possession of
all or any portion of such furniture, fixtures, equipment and other property
to any person ("CLAIMANT") who presents to Landlord a copy of any

                                       11
<PAGE>

instrument represented by Claimant to have been executed by Tenant (or any
predecessor of Tenant) granting Claimant the right under various circumstances
to take possession of such furniture, fixtures, equipment or other property,
without the necessity on the part of Landlord to inquire into the authenticity
or legality of said instrument. The rights of Landlord herein stated shall be in
addition to any and all other rights that Landlord has or may hereafter have at
law or in equity, and tenant stipulates and agrees that the rights granted
Landlord under this paragraph are commercially reasonable.

22.     MORTGAGES.

Subject to Tenant receiving a non-disturbance agreement from the mortgagee of
the Property, Tenant accepts this Lease subject and subordinate to any
mortgages and/or deeds of trust now or at any time hereafter constituting a
lien or charge upon the Premises or the improvements situated thereon or the
Building, provided, however, that if the mortgagee, trustee or holder of any
such mortgage or deed of trust elects to have Tenant's interest in this Lease
superior to any such instrument, then by notice to Tenant from such
mortgagee, trustee or holder, this Lease shall be deemed superior to such
lien, whether this lease was executed before or after said mortgage or deed
of trust. If any mortgage, deed of trust or security agreement is enforced by
the mortgagee, the trustee, or the secured party, Tenant shall, upon request,
attorn to the mortgagee or purchaser at such foreclosure sale, or any person
or party succeeding to the interest of Landlord as a result of such
enforcement, as the case may be, and execute instrument(s) confirming such
attornment. In the event of such enforcement and upon Tenant's attornment as
aforesaid, Tenant will automatically become the tenant of the successor to
Landlord's interest without change in the terms or provisions of this Lease;
provided, however, that such successor to Landlord's interest shall not be
bound by (a) any payment of Rent for more than one month in advance (except
prepayments for security deposits, if any), or (b) any amendments or
modifications of this Lease made without the prior written consent of such
Lessor or mortgagee. Tenant, at any time hereafter on demand, shall execute
any instruments, releases or other documents that may be required by any
mortgagee, trustee or holder for the purpose of subjecting and subordinating
this Lease to the lien of any such mortgage or to confirm Tenant's agreement
of attornment. In consideration of Tenant's subordination and attornment
agreements set forth above, Landlord shall provide Tenant with a
non-disturbance agreement from its lender. Tenant shall not terminate this
Lease or pursue any other remedy available to Tenant hereunder for any
default on the part of Landlord without first giving written notice by
certified or registered mail, return receipt requested, to any mortgagee,
trustee or holder of any such mortgage or deed of trust, the name and post
office address of which Tenant has received written notice, specifying the
default in reasonable detail and affording such mortgagee, trustee or holder
a reasonable opportunity (but in no event less than thirty (30) days) to make
performance, at its election, for and on behalf of Landlord.

23.     MECHANIC'S LIENS.

Tenant has no authority, express or implied to create or place any lien or
encumbrance of any kind or nature whatsoever upon, or in any manner to bind,
the interest of Landlord or Tenant in the Premises. Tenant will save and hold
Landlord harmless from any and all loss, costs expense, including without
limitation attorneys' fees, based on or arising out of asserted claims or
liens against the leasehold estate or against the right, title and interest
of the Landlord in the Premises or under the terms of this Lease.

24.     MISCELLANEOUS.

        A. INTERPRETATION. The captions inserted in this lease are for
convenience only and in no way define, limit or otherwise describe the scope
or intent of this Lease, or any provision hereof, or in any way affect the
interpretation of this Lease. Any reference in this Lease to rentable area
shall mean the gross rentable area as determined by the roofline of the
building in question.

        B. BINDING EFFECT. Except as otherwise herein expressly provided, the
terms, provisions and covenants and conditions in this Lease shall apply to,
inure to the benefit of and be binding upon the parties hereto and upon their
respective heirs, executors, personal representatives, legal representatives,
successors and assigns. Landlord shall have the right to transfer and assign,
in whole or in part, its rights and obligations in the Premises and in the
Building and other property that are the subject of this Lease.

        C. EVIDENCE OF AUTHORITY. Tenant agrees to furnish to Landlord,
promptly upon demand, a corporate resolution, proof of due authorization by
partners or other appropriate documentation evidencing the due authorization
of such party to enter into this Lease.

        D. FORCE MAJEURE. Landlord shall not be held responsible for delays
in the performance of its obligations hereunder when caused by material
shortages, acts of God, labor disputes or other events beyond the control of
Landlord.

                                       12
<PAGE>

        E. PAYMENTS CONSTITUTE RENT. Notwithstanding anything in this Lease
to the contrary, all amounts payable by Tenant to or on behalf of Landlord
under this Lease, whether or not expressly denominated as rent, shall
constitute rent.

        F. ESTOPPEL CERTIFICATES. Tenant agrees from time to time, within
ten (10) days after request of Landlord to deliver to Landlord, or Landlord's
designee, an estoppel certificate stating that this Lease is in full force
and effect, the date to which rent has been paid, the unexpired term of this
Lease, any defaults existing under this Lease (or the absence thereof) and
such other factual or legal matters pertaining to this Lease as may be
requested by Landlord. It is understood and agreed that Tenant's obligation
to furnish such estoppel certificates in a timely fashion is a material
inducement for Landlord's execution of this Lease. Tenant's failure to timely
comply with the requirements of this Paragraph 24F will constitute an Event
of Default under this Lease, notwithstanding the existence of any notice and
opportunity to cure periods which would otherwise apply to extend the time
period within which Tenant may respond.

        G. ENTIRE AGREEMENT. This Lease constitutes the entire understanding
and agreement of Landlord and Tenant with respect to the subject matter of
this Lease, and contains all of the covenants and agreements of Landlord and
Tenant with respect thereto. Landlord and Tenant each acknowledge that no
representations, inducements, promises or agreements, oral or written, have
been made by Landlord or Tenant, or anyone acting on behalf of Landlord or
Tenant, which are not contained herein, and any prior agreements, promises,
negotiations or representations not expressly set forth in this Lease are of
no force or effect. EXCEPT AS SPECIFICALLY PROVIDED IN THIS LEASE, TENANT
HEREBY WAIVES THE BENEFIT OF ALL WARRANTIES, EXPRESS OR IMPLIED, WITH RESPECT
TO THE PREMISES, INCLUDING WITHOUT LIMITATION ANY IMPLIED WARRANTY THAT THE
PREMISES ARE SUITABLE FOR ANY PARTICULAR PURPOSE. Landlord's agents and
employees do not and will not have the authority to make exceptions, changes
or amendments to this Lease, or factual representations not expressly
contained in this Lease. Under no circumstances shall Landlord or Tenant be
considered an agent of the other. This Lease may not be altered, changed or
amended except by an instrument in writing signed by both parties hereto.

        H. SURVIVAL OF OBLIGATIONS. All obligations of Tenant hereunder not
fully performed as of the expiration or earlier termination of the term of
this Lease shall survive the expiration or earlier termination of the term
hereof, including without limitation all payment obligations with respect to
taxes and insurance and all obligations concerning the condition and repair
of the Premises. Upon the expiration or earlier termination of the term
hereof, and prior to Tenant vacating the Premises, Tenant shall pay to
Landlord any amount reasonable estimated by Landlord as necessary to put the
Premises in good condition and repair, reasonable wear and tear excluded,
including without limitation the cost of repairs to and replacements of all
heating and air conditioning systems and equipment therein. Tenant shall
also, prior to vacating the Premises, pay to Landlord the amount, as
estimated by Landlord, of Tenant's obligation hereunder for real estate taxes
and insurance premiums for the year in which the Lease expires or terminates.
All such amounts shall be used and held by Landlord for payment of such
obligations of Tenant hereunder, with Tenant being liable for any additional
costs therefore upon demand by Landlord, or with any excess to be returned to
Tenant after all such obligations have been determined and satisfied, as the
case may be. Any Security Deposit held by Landlord may, at Landlord's option,
be credited against any amounts due from Tenant under this Paragraph 24H.

        I. SEVERABILITY OF TERMS. If any clause or provision of this Lease is
illegal, invalid or unenforceable under present or future laws effective
during the term of this Lease, then, in such event, it is the intention of
the parties hereto that the remainder of this Lease shall not be affected
thereby, and it is also the intention of the parties to this Lease that in
lieu of each clause or provision of this lease that is illegal, invalid or
unenforceable, there be added, as a part of this Lease, a clause or provision
as similar in terms to such illegal, invalid or unenforceable clause or
provision as may be possible and be legal, valid and enforceable.

        J. EFFECTIVE DATE. All references in this Lease to "the date hereof"
or similar references shall be deemed to refer to the last date, in point of
time, on which all parties hereto have executed this Lease.

        K. BROKERS' COMMISSION. Tenant represents and warrants that it has
dealt with Oxford Commercial and Pyramid Properties, Inc. in connection with
this transaction or future related transactions and that no other broker,
agent or other person brought about this transaction, and Tenant agrees to
indemnify and hold Landlord harmless from and against any claims by any
broker, agent or other person claiming a commission or other form of
compensation by virtue of having dealt with Tenant with regard to this
leasing transaction.

        L. AMBIGUITY. Landlord and tenant hereby agree and acknowledge that
this Lease has been fully reviewed and negotiated by both Landlord and
Tenant, and that Landlord an Tenant have each had the opportunity to have
this Lease reviewed by their respective legal counsel, and, accordingly, in
the event of any ambiguity herein, Tenant does hereby waive the rule of
construction that such ambiguity shall be resolved against the party who
prepared this Lease.

                                       13
<PAGE>

        M. THIRD PARTY RIGHTS. Nothing herein expressed or implied is
intended, or shall be construed, to confer upon or give to any person or
entity, other than the parties hereto, any right or remedy under or by reason
of this Lease.

        N. EXHIBITS AND ATTACHMENTS. All exhibits, attachments, riders and
addenda referred to in this Lease, and the exhibits listed herein below and
attached hereto, are incorporated into this lease and made a part hereof for
all intents and purposes as if fully set out herein. All capitalized terms
used in such documents shall, unless otherwise defined therein, have the same
meanings as are set forth herein.

        0. APPLICABLE LAW. This Lease has been executed in the State of Texas
and shall be governed in all respects by the laws of the State of Texas. It
is the intent of Landlord and Tenant to conform strictly to all applicable
state and federally usury laws. All agreements between Landlord and Tenant,
whether now existing or hereafter arising and whether written or oral, are
hereby expressly limited so that in no contingency or event whatsoever shall
the amount contracted for, charged or received by Landlord for the use
forbearance or retention of money hereunder or otherwise exceed the maximum
amount which Landlord is legally entitled to contract for, charge or collect
under the applicable state or federal law. If, from any circumstance
whatsoever, fulfillment of any provision hereof at the time performance of
such provision shall be due shall involve transcending the limit of validity
prescribed by law, then the obligation to be fulfilled shall be automatically
reduced to the limit of such validity, and if from any such circumstance
Landlord shall ever receive as interest or otherwise an amount in excess of
the maximum that can be legally collected, then such amount which would be
excessive interest shall be applied to the reduction of rent hereunder, and
if such amount which would be excessive interest exceeds such rent, then such
additional amount shall be refunded to Tenant.

25.     NOTICES.

Each provision of this instrument or of any applicable governmental laws,
ordinances, regulations and other requirements with reference to the sending,
mailing or delivering of notice or the making of any payment by Landlord to
Tenant or with reference to the sending, mailing or delivering of any notice or
the making of any payment by Tenant to Landlord shall be deemed to be complied
with when and if the following steps are taken:

        (i) All rent and other payments required to be made by Tenant to
Landlord hereunder shall be payable to Landlord at the address for Landlord set
forth below or at such other address as Landlord may specify from time to time
by written notice delivered in accordance herewith. Tenant's obligation to pay
rent and any other amounts to Landlord under the terms of this lease shall not
be deemed satisfied until such rent and other amounts have been actually
received by Landlord.

        (ii) All payments required to be made by Landlord to Tenant hereunder
shall be payable to Tenant at the address set forth below, or at such other
address within the continental United States as Tenant may specify from time to
time by written notice delivered in accordance herewith.

        (iii) Except as expressly provided herein, any written notice, document
or payment required or permitted to be delivered hereunder shall be deemed to be
delivered when received or, whether actually received or not, when deposited in
the United States Mail, postage prepaid, Certified or Registered Mail, addressed
to the parties hereto at the respective addresses set out below, or at such
other address as they have theretofore specified by written notice delivered in
accordance herewith.

        LANDLORD'S ADDRESS:

        S.W. Office Building, Ltd.
        c/o Pyramid Properties
        1717 West Sixth Street, Suite 380
        Austin, Texas 78703

        TENANT'S ADDRESS:

        (Prior to Commencement Date)

        Silicon Laboratories, Inc.
        -------------------------------
        2024 E. St. Elmo Road
        -------------------------------
        Austin TX 78744-1018
        -------------------------------

        (After Commencement Date)

           Silicon Laboratories, Inc.
           4609 Southwest Parkway
           Austin, TX 78735

                                       14
<PAGE>

        Silicon Laboratories, Inc.
        4609 Southwest Parkway
        Austin, Texas 78735

26.     EXHIBITS.

EXHIBITS "A", "B" "C" and "D" are attached hereto and are hereby incorporated
into this Lease as fully as if herein set forth at length.

27.     TENANT'S RIGHT TO OBTAIN FINANCING FOR AND TO LEASE TENANT'S PERSONAL
PROPERTY AND EQUIPMENT.

        Tenant shall have the right to grant any security interests in Tenant's
REMOVABLE furniture, fixtures and equipment located in the Premises for the
purpose of securing any indebtedness provided by a third party. Tenant may also
lease any such furniture, fixtures and/or equipment from one or more equipment
lessors and grant security interests in such furniture, fixtures and/or
equipment to such equipment lessors in connection with such leases. Upon request
Landlord will execute one or more consent and/or subordination agreements
subordinating any landlord's lien rights held by Landlord to any such security
interests or leases. Notwithstanding the foregoing, in no event will Tenant
have the right to grant any lien, mortgage or security interest in any portion
of the Building or in this Lease.

28.     LANDLORD'S CONDITIONS TO PERFORMANCE

        Notwithstanding anything contained in this Lease to the contrary,
Landlord's obligations hereunder are specifically conditioned upon Landlord
achieving substantial completion of the Premises not later than March 31, 1999.
In the event Landlord does not achieve substantial completion of the Premises by
March 31, 1999, Tenant, as Tenant's sole and exclusive remedy, may terminate
this Lease in writing at any time after March 31, 1999 and before Landlord
achieves substantial completion of the Premises. In the event Tenant terminates
this Lease pursuant to this paragraph, Landlord will return all advance payments
of rent and Security Deposits theretofore paid to Landlord by Tenant and all
Letters of Credit theretofore delivered to Landlord by Tenant and will reimburse
and refund Tenant for all moneys theretofore expended by Tenant in connection
with the construction of the Interior Improvements pursuant to paragraph 5b of
EXHIBIT "C" attached hereto, as well as any moneys remaining in the escrow
account for Tenant's Proportionate Share of the cost of the Interior
Improvements.

        EXECUTED BY LANDLORD, this 26th day of June, 1998.

                             S.W. AUSTIN OFFICE BUILDING, LTD., A TEXAS LIMITED
                             PARTNERSHIP

                             By:  /s/ [ILLEGIBLE]
                                ----------------------------------------------
                             Name:    [ILLEGIBLE]
                                  --------------------------------------------
                             Title:      Partner
                                   -------------------------------------------

        EXECUTED BY TENANT, this 25th day of June, 1998.

                             SILICON LABORATORIES, INC., A DELAWARE CORPORATION

                             By:  /s/ Navdeep Sooch
                                ----------------------------------------------
                             Name:    NAVDEEP SOOCH
                                  --------------------------------------------
                             Title:    PRESIDENT
                                   -------------------------------------------

ATTACH EXHIBITS:

EXHIBIT "A" - Legal Description of the Property and Floor Plan of the Premises
EXHIBIT "B" - Schematic Plans for the Building
EXHIBIT "C" - Work Letter for Interior Improvements
EXHIBIT "D" - Renewal Option

                                       15
<PAGE>

                                   EXHIBIT "A"
                       LEGAL DESCRIPTION OF THE PROPERTY

BUILDING:    Tech Center Southwest

ADDRESS:     4609 Southwest Parkway, Suite 100
             Austin, Texas 78735

LEGAL
DESCRIPTION: Lot 1, Boston 290 Office Park Section Two-A, a subdivision in
             Travis County, Texas, according to the map or plat of record in
             Volume 100, Pages 58-59 of the Plat Records of Travis County,
             Texas.

<PAGE>

                                  EXHIBIT "A"
                           FLOOR PLAN OF THE PROMISES

                       To be attached prior to execution

                                   [FLOOR PLAN]

<PAGE>

                                  EXHIBIT "A"
                            SITE PLAN OF THE PROJECT

                                   [SITE PLAN]

<PAGE>

                                    EXHIBIT "B"
                               PLANS FOR THE PROJECT

<PAGE>

                                     [PHOTO]

<PAGE>

                                  EXHIBIT "C"
                                  WORK LETTER

1.      INTERIOR IMPROVEMENTS.

        Reference herein to "INTERIOR IMPROVEMENTS" shall include all work to
be done in the Premises pursuant to the Interior Improvements Plans (defined
in paragraph 2 below), including, but not limited to, partitioning, doors,
ceilings, floor coverings, wall finishes (including paint, wallpaper, fabric
and all other coverings), electrical (including lighting, switching,
telephones, outlets, etc.), plumbing, heating, ventilating and air
conditioning, fire protection, cabinets, and other millwork, and any other
improvements required by Tenant which are not included in the Plans for the
Project. Landlord and Tenant hereby agree that unless otherwise agreed to,
the design architect for the Interior Improvements will be RTG Partners (the
"INTERIOR DESIGN ARCHITECT") and the general contractor for the construction
of the Interior Improvements will be Marcon Construction Company (the
"CONTRACTOR").

2.      INTERIOR IMPROVEMENTS PLANS.

        Immediately after execution of the Lease, Tenant shall meet with
representatives of the Interior Design Architect for the purpose of promptly
preparing a space plan and selecting materials and finishes for the layout
and construction of improvements in the Premises. After the preparation of
the space plan and after Tenant's written approval thereof, the Interior
Design Architect shall prepare final working drawings and specifications for
the Interior Improvements based on the space plan and submit the same to
Tenant for Tenant's approval. Such final working drawings and specifications
are referred to herein as the "INTERIOR IMPROVEMENTS PLANS". A copy of the
space plan and the Interior Improvements Plans, and each revised version
thereof, shall also be submitted to Landlord for Landlord's reasonable
approval simultaneously with submission to Tenant. Tenant shall promptly
review each version of the space plan and the Interior Improvements Plans and
deliver any comments to the Interior Design Architect expeditiously, and in
no event later than five (5) days after receipt of the same, so that the
Interior Improvements Plans are finally approved by Tenant within thirty (30)
days after the date of this Lease. After approval of the Interior
Improvements Plans by Landlord and Tenant, the same shall be submitted to the
appropriate governmental body by the Interior Design Architect for plan
checking and issuance of a building permit. The Interior Design Architect,
with Tenant's cooperation, shall cause to be made to the Interior
Improvements Plans any changes necessary to obtain the building permit.
Landlord's approval of the Interior Improvements Plans shall create or impose
no liability or responsibility on Landlord for their completeness, design
sufficiency or compliance with all applicable laws, rules and regulations of
governmental agencies or authorities. Tenant shall work together with the
Interior Design Architect, Landlord and the Contractor diligently to finally
approve the Interior Improvements Plans and the final pricing for the
construction of the Interior Improvements not later than sixty (60) days
after the date of this Lease.

3.      FINAL PRICING AND DRAWING SCHEDULE.

        After the approval of the Interior Improvements Plans by Landlord and
Tenant, the Interior Improvement Plans shall be submitted to the appropriate
governmental body by the Interior Design Architect for plan checking and the
issuance of a building permit. Landlord, with Tenant's cooperation, shall
cause to be made to Tenant Improvement Plans any changes necessary to obtain
the building permit. Concurrently with the plan checking, Landlord shall have
prepared a final pricing for Tenant's approval, taking into account any
modifications which may be required to reflect changes in Tenant Improvement
Plans required by the city or county in which the Premises are located. After
final approval of the Tenant Improvement Plans, no further changes may be
made thereto without the prior written approval from both Landlord and
Tenant, and then only after agreement by Tenant to pay any excess costs
resulting from the design and/or construction of such changes.

4.      CONSTRUCTION OF INTERIOR IMPROVEMENTS.

        After the Interior Improvement Plans have been prepared and approved,
the final pricing, based on subcontractors' competitive bids, has been
approved, a building permit for the Interior Improvements has been issued,
and the construction of the Project has progressed to the point that the
Contractor can begin construction of the Interior Improvements, the
Contractor shall begin construction and installation of the Interior
Improvements in accordance with Interior Improvement Plans. Landlord shall
supervise the completion of such work and shall secure substantial completion
of the work in a timely manner. The cost of such work shall be paid as
provided in Section 5 below. Landlord shall not be liable for any direct or
indirect damages as a result of delays in construction beyond Landlord's
reasonable control arising as a result of acts of God or delays by Tenant or
Tenant's agents or employees.

5.      PAYMENT FOR THE INTERIOR IMPROVEMENTS.

        a. Tenant shall be responsible for the entire cost of the design,
construction and permitting of the Interior Improvements. In order to defray a
portion of the cost of the Interior Improvements, however, Landlord hereby
grants to Tenant an "INTERIOR IMPROVEMENTS ALLOWANCE" in the amount of Six
Hundred Eighty Thousand Four Hundred Dollars ($680,400.00). The Interior
Improvements Allowance shall be used only for:

                (1) Payment of the cost of space planning; provided, however,
        that not more than $0.10 per rentable square foot) of the Interior
        Improvements Allowance may be used for such planning work.

                (2) Payment of the cost of preparing the Interior Improvements
        Plans, including mechanical, electrical, plumbing and structural
        drawings, and of all other aspects necessary to complete the Interior
        Improvements Plans; provided, however, that not more than $0.35 per
        rentable square foot of the Interior Improvements Allowance may be used
        for plan preparation.

                (3) Payment of plan check, permit, and license fees relating to
        construction of the Interior Improvements.

<PAGE>

                (4) Construction of the Interior Improvements including, but not
        limited to, the following:

                        (a) Installation within the Premises of all
                partitioning, doors, cabinets, floor coverings, ceiling, wall
                coverings and painting, millwork, and similar items;

                        (b) All electrical wiring, lighting fixtures, outlets
                and switches, and other electrical work to be installed within
                the Premises;

                        (c) The furnishing and installation of all duct work,
                terminal boxes, diffusers, and accessories required for the
                completion of the heating, ventilation and air conditioning
                systems within the Premises;

                        (d) Any additional Tenant requirements, including, but
                not limited to, odor control, special heating, ventilation and
                air conditioning, noise or vibration control, or other special
                systems;

                        (e) All fire and life safety control systems such as
                fire walls, halon, fire alarms, including piping, wiring and
                accessories installed within the Premises;

                        (f) All plumbing, fixtures, pipes and accessories to be
                installed within the Premises;

                        (g) Testing and inspection costs; and

                        (h) Contractors' fees, including but not limited to any
                fees based on general conditions, and supervisory fees.

                (5) All other costs to be expended by Landlord in the
        construction of the Interior Improvements in accordance with the
        Interior Improvements Plans.

        b. In the event that the cost of installing the Interior
Improvements, as established by Landlord's final pricing schedule, shall
exceed the Interior Improvements Allowance, or if any of the Interior
Improvements do not qualify for payment out of the Interior Improvement
Allowance as provided in Paragraph 5 a, above, the amount which is in excess
of the Interior Improvements Allowance (the "EXCESS") shall be paid by
Tenant. Not later than sixty (60) days after the date of this Lease, Tenant
shall deposit the Excess in a segregated account (the "ESCROW ACCOUNT") at a
bank or savings institution in Austin, Texas acceptable to Landlord and upon
which Landlord has sole signatory and withdrawal authority. Upon request by
Landlord, Tenant will provide Landlord with evidence of the deposit of the
Excess into the Escrow Account. Landlord shall pay Tenant's Proportionate
Share of the cost of the construction of the Interior Improvements out of
such Escrow Account periodically as such costs are incurred. As the
construction of the Interior Improvements proceeds, Landlord will
periodically provide Tenant with an invoice for Tenant's Proportionate Share
of the cost of the Interior Improvements. "Tenant's Proportionate Share" of
such costs from time to time shall be equal to the total cost of the Interior
Improvements to the date of such invoice, minus the amount previously paid by
Tenant under this paragraph, multiplied by a fraction, the numerator of which
is the original amount of the Excess and the denominator of which is the
total cost of the Interior Improvements. Simultaneously with delivery to
Tenant of the backup invoice for each periodic installment of the cost to
construct the Interior Improvements, Landlord will be authorized to draw
Tenant's Proportionate Share of such costs out of the Escrow Account. Subject
to the foregoing, Landlord will make payment to all suppliers of materials
and labor in connection with the construction of the Interior Improvements.

        c. In the event that, after the Interior Improvement Plans have been
prepared and the final pricing therefor has been agreed to between Landlord
and Tenant, Tenant shall require any changes or substitutions to the Interior
Improvements Plans, any additional costs related thereto shall be paid by
Tenant to Landlord prior to the commencement of construction of the Interior
Improvements. Landlord shall have the right to decline Tenant's request for
change to the Interior Improvement Plans if, in Landlord's opinion, such
changes would unreasonably delay construction of the Interior Improvements.

        d. No unused portion of the Interior Improvement Allowance shall be
refunded to Tenant or available to Tenant as a credit against any obligations
of Tenant under the Lease.

        e. No portion of the Interior Improvements Allowance will be
disbursed by Landlord until such time as the Interior Improvements Plans have
been finalized and agreed to by Landlord and Tenant, the final pricing for
the construction and installation of the Interior Improvements has been
agreed to by Tenant and any Excess (as such term is defined in paragraph 5 b,
above) has been deposited by Tenant into the account referred to in paragraph
5b, above.

6.      WARRANTY.

        Landlord will provide a one year warranty on the construction and
installation of the Interior Improvements. Landlord will pass any
subcontractors' and manufacturers' warranties on all appliances and equipment
but Landlord will not provide any warranty with respect to appliances or
equipment installed for Tenant.

<PAGE>

                                  EXHIBIT "D"
                                 RENEWAL OPTION

1. OPTION TO RENEW TERM.

        Landlord grants to Tenant the right (the "RENEWAL OPTION") to renew
this Lease with respect to all, but not less than all, of the Premises for
one (1) additional term of five (5) years (the "RENEWAL TERM"), such Renewal
Term commencing upon the expiration of the initial Term and continuing for
five (5) years thereafter. The Renewal Option is granted on the same terms,
conditions and covenants set forth in this Lease, except as provided below.
The Renewal Option may be exercised only by written notice (the "NOTICE")
delivered to Landlord no earlier than two hundred forth (240) days before,
and no later than one hundred eighty (180) days before, the expiration of the
initial Lease Term. If Tenant fails to deliver Landlord written Notice of the
exercise of the Renewal Option within the prescribed time period, the Renewal
Option shall lapse, and thereafter shall be null and void and of no further
force or effect and Tenant shall be deemed to have waived its right to renew
or extend the Lease Term under this EXHIBIT "D". The Renewal Option may only
be exercised by Tenant on the express condition that, at the time of the
exercise, Tenant is not in default under any of the provisions of this Lease.
The Renewal Option is personal to Tenant and may not be exercised by any
assignee or subtenant without Landlord's written consent. In addition, Tenant
shall not have the right to exercise the Renewal Option of any portion of the
Premises is subleased or if any portion of the Lease has been assigned by
Tenant.

        a.      Upon receipt of the Renewal Option Notice, Landlord will deliver
                Tenant notice of the Base Rent to be in effect for the Renewal
                Term. In no event shall the Base Rent for the Renewal Term be
                less than the rate of Base Rent in effect at the expiration of
                the initial Term. Such Base Rent shall be equal to market rent
                for comparable space as reasonably determined by Landlord, it
                being understood that as of the date of this Lease, there is no
                space which is comparable to the Premises in the vicinity of the
                Premises. Upon receipt of Landlord's determination of the Base
                Rent for the Renewal Term, Tenant shall have the right to accept
                or reject the same. If Tenant specifically rejects Landlord's
                designation of Base Rent for the Renewal Term in writing within
                five (5) days after Landlord has notified Tenant of the Base
                Rent for the Renewal Term then Tenant, as its sole remedy, will
                be deemed to have revoked its election to renew the term of this
                Lease, whereupon the Renewal Option will, be deemed to have been
                waived by Tenant and the Renewal Option shall lapse, and
                thereafter shall be null and void and of no further force or
                effect. If Tenant fails to deliver notice of rejection of the
                Base Rent within the five (5) day period referred to above,
                Tenant shall be deemed to have accepted Landlord's designation
                of Base Rent for the Renewal Term and Tenant may not thereafter
                revoke its election to Renew.

        b.      Tenant shall pay Base Rent during the Renewal Term to Landlord
                in monthly installments in the amount or amounts determined
                pursuant to paragraph a, above, along with all other Rent and
                other amounts due under the Lease, including without limitation,
                all rental adjustments pursuant to Paragraph 2C of the Lease.

        c.      Landlord shall not be obligated to make any alterations or
                improvements to the Premises during or in connection with the
                Renewal Term.

        d.      Except for the Renewal Option described above, Tenant shall have
                no further right to renew or extend this Lease.

<PAGE>

                       FIRST AMENDMENT TO LEASE AGREEMENT

     THIS FIRST AMENDMENT TO LEASE AGREEMENT (this "FIRST AMENDMENT") is
entered into by and between S.W. AUSTIN OFFICE BUILDING, LTD., A TEXAS
LIMITED PARTNERSHIP ("LANDLORD"), and SILICON LABORATORIES, INC., A DELAWARE
CORPORATION ("TENANT") effective as of the 29th day of July, 1998.

                                    RECITALS

     A.   Landlord and Tenant executed a certain Lease Agreement (the "LEASE")
dated June 25, 1998, covering approximately 37,800 square feet of space in a
building to be built (the "BUILDING") located at 4635 Boston Lane, Austin, Texas
78735.

     B.   The Lease and the Ancillary Agreements (hereinafter defined)
incorrectly refer to the address of the Building as being 4609 Southwest Parkway
instead of 4635 Boston Lane.

     C.   Landlord and Tenant desire to amend the Lease and the Ancillary
Agreements to correct the address of the Building stated therein.

     NOW, THEREFORE, in consideration of the premises, and for Ten and No/100
Dollars ($10.00) and other good and valuable consideration, Landlord and Tenant
agree as follows:

                                   AGREEMENTS

     1.   AMENDMENT TO LEASE AND ANCILLARY DOCUMENTS. All references in the
Lease and in all documents and instruments executed in connection therewith,
including, without limitation, that certain Side Letter Agreement (regarding
environmental report), that certain Letter Agreement (regarding approval of the
issuer of the Letter of Credit and zoning), that certain Parking Structure
Agreement, and that certain Right of First Refusal and Option Agreement
(collectively, the "ANCILLARY AGREEMENTS") to the address of the Building as
being 4609 Southwest Parkway are hereby amended to provide that the address of
the Building is 4635 Boston Lane, Austin, Texas 78735.

     2.   CAPITALIZED TERMS. All capitalized terms used herein shall have the
meaning ascribed to them in the Lease unless specifically defined herein.

     3.   EFFECT OF AMENDMENT. The Lease and the Ancillary Agreements, as hereby
amended, shall continue in full force and effect. All of the other terms of the
Lease and the Ancillary Agreements shall remain unchanged and shall continue in
full force and effect.

     4.   COUNTERPARTS. This First Amendment may be executed in several
counterparts and all counterparts so executed shall together be deemed to
constitute one final agreement as if signed by all parties hereto and all
counterparts shall be deemed to be an original.

                                   Page 1 of 2

<PAGE>

     5.   AMENDMENT CONTROLLING. The provisions of this First Amendment shall
supersede and control over any conflicting provisions in the Lease and the
Ancillary Agreements.

          EXECUTED to be effective as of the date first above written.

                                   LANDLORD:

                                   S.W. AUSTIN OFFICE BUILDING, LTD., A
                                   TEXAS LIMITED PARTNERSHIP

                                   By: [ILLEGIBLE]
                                      ----------------------------
                                   Name:
                                        --------------------------
                                   Title:
                                         -------------------------

                                   TENANT:

                                   SILICON LABORATORIES, INC., A DELAWARE
                                   CORPORATION

                                   By:  /s/ Navdeep Sooch
                                      ----------------------------
                                   Name:  Navdeep S. Sooch
                                        --------------------------
                                   Title:     President
                                         -------------------------

                                   Page 2 of 2

<PAGE>

                       SECOND AMENDMENT TO LEASE AGREEMENT

     THIS SECOND AMENDMENT TO LEASE AGREEMENT (this "SECOND AMENDMENT") is
entered into by and between S.W. AUSTIN OFFICE BUILDING, LTD., A TEXAS
LIMITED PARTNERSHIP ("LANDLORD"), and SILICON LABORATORIES, INC., A DELAWARE
CORPORATION ("TENANT"), effective as of the 20th day of August, 1998.

                                    RECITALS

     A.   Landlord and Tenant executed a certain Lease Agreement (the "ORIGINAL
LEASE") dated June 25, 1998, covering approximately 37,800 square feet of space
in a building to be built (the "BUILDING") located at 4635 Boston Lane, Austin,
Texas 78735.

     B.   Landlord and Tenant have heretofore amended the Original Lease
pursuant to that certain First Amendment to Lease Agreement dated July 29,
1998 (the "FIRST AMENDMENT").

     C.   Tenant desires to delay the construction of the Interior Improvements
and the Commencement Date of the Lease Term and to provide for an option to
terminate the Lease.

     D.   In order to accommodate the foregoing, Landlord and Tenant now desire
to further amend the Lease as hereinafter set forth.

     NOW, THEREFORE, in consideration of the premises, and for Ten and No/100
Dollars ($10.00) and other good and valuable consideration, Landlord and Tenant
agree as follows:

                                   AGREEMENTS

     1.   AMENDMENT TO LEASE AND ANCILLARY AGREEMENTS. The Original Lease, as
amended by the First Amendment, is hereinafter referred to as the "Lease".

     2.   PAYMENT FOR BUILDING SHELL CHANGE ORDERS. Prior to the execution
hereof, Tenant has remitted payment to Landlord for two change orders to the
base building requested by Tenant in the respective amounts of $29,720.00 and
$11,950.00. Landlord and Tenant agree that the amounts stated in the foregoing
sentence constitute reimbursements to Landlord for the cost of changes to the
Building which were requested by Tenant and therefore, such amounts are not
refundable to Tenant under any circumstances.

     3.   REVISED DUE DATE FOR DELIVERY OF LETTER OF CREDIT. The Letter of
Credit referenced in SECTION 2 of the Lease shall be delivered to Landlord on or
before September 8, 1998.

     4.   LIMITED RIGHT OF TERMINATION. Landlord hereby grants Tenant a limited
right of termination of the Lease as set forth in this paragraph 4. Tenant may
exercise the option to terminate the Lease by failing to deliver the Letter of
Credit by September 8, 1998, for any

                                   Page 1 of 5

<PAGE>

reason. Tenant's failure to deliver the Letter of Credit in the required form
by September 8, 1998 will constitute an irrevocable election on Tenant's part
to terminate the Lease. In the event the Lease is terminated pursuant to this
paragraph, Landlord, as Landlord's sole and exclusive remedy, will retain the
$151,200.00 lease termination cash security deposit heretofore tendered by
Tenant as a lease termination fee and not as a penalty. It is agreed that the
$151,200 fee is a 2 reasonable fee and constitutes just compensation for the
right to terminate the Lease as set forth above.

     5.   OXFORD COMMERCIAL, INC. COMMISSION IN THE EVENT OF TERMINATION OF
LEASE. In the event the Lease is terminated pursuant to Paragraph 4, above,
Tenant will assume all responsibility for payment of all leasing commissions, if
any, due or payable to Oxford Commercial, Inc. in connection with the Lease.
Oxford Commercial, Inc. agrees to look only to Tenant for payment of all
compensation due or to become due in connection with the Lease. In the event of
termination of the Lease in accordance with Paragraph 4, above, Oxford
Commercial, Inc. and Tenant will indemnify, defend and hold Landlord harmless
from any cost or claim of Oxford Commercial, Inc., or any agent, broker or
person claiming a right to a leasing commission or fee by, through or under
Oxford Commercial, Inc., by reason of the Lease. The indemnity obligations set
forth herein shall survive any termination or cancellation of the Lease
notwithstanding any contrary provision contained herein or therein. Oxford
Commercial, Inc. hereby joins in the execution of this Second Amendment to
confirm its agreement to be bound by the provisions of this Paragraph 5.

     6. DELAY OF COMMENCEMENT OF CONSTRUCTION OF INTERIOR IMPROVEMENTS. At
Tenant's request, Landlord agrees to delay the commencement of construction of
the Interior Improvements until finalization of the Interior Improvements Plans
as set forth in paragraph 7, below. It is acknowledged and agreed that Landlord
may commence construction of the Interior Improvements at any time after the
finalization of the Interior Improvements Plans in order to meet Landlord's
construction schedule. Pursuant to paragraph 10, below, Tenant is not required
to pay the Excess into the Escrow Account until January 4, 1999. Landlord's
election to commence construction of the Interior Improvements prior to January
4, 1999, will not operate to accelerate Tenant's obligation to pay the Excess
into the Escrow Account prior to January 4, 1999.

     7.   FINALIZATION OF INTERIOR IMPROVEMENTS PLANS. In the event the Lease is
not terminated as aforesaid, Tenant will proceed to finalize the Interior
Improvements Plans not later than November 30, 1998, in order to enable Landlord
to achieve substantial completion of the Interior Improvements in a timely
manner.

     8.   DELAY OF COMMENCEMENT DATE AND INTERIM RENT PAYMENTS. The Commencement
Date shall be determined as set forth in SECTION 1B of the Lease except that
the period from the Effective Date until January 1, 1999 shall not be includible
as a Tenant Delay for purposes of SECTION 1B(ii) of the Lease. The Base Rent and
other charges provided for in the Lease shall be due and payable in the manner
and in the amounts set forth in the Lease, beginning on the Commencement Date.
As consideration to Landlord (and provided that the Lease is not

                                  Page 2 of 5

<PAGE>

terminated as provided in paragraph 4, above), Tenant will pay Landlord, in
advance, without demand, deduction or set off, the sum of $20,000.00 per
month as interim rent (the "INTERIM RENT") commencing on October 1, 1998 and
continuing through the month of December, 1998, for a total of $60,000.00 in
Interim Rent to be paid in $20,000.00 increments on October 1, 1998, November
1, 1998 and December 1, 1998.

     9.   SUBLEASING. Tenant does not intend to initially occupy the entirety of
the Building. In order to defray a portion of the costs associated with leasing
the Premises, however, Tenant intends to sublease portions of the Premises to
third party users. Nothing in the foregoing sentence will be deemed to modify
the provisions of SECTION 16 of the Lease or Landlord's obligations with respect
thereto. Specifically, it is hereby confirmed that Landlord has the right to
approve any subtenant of a portion of the Premises in accordance with the
provisions of SECTION 16 of the Lease and Landlord has no obligation to assist
Tenant in locating any acceptable subtenants.

     10.  CONSTRUCTION OF INTERIOR IMPROVEMENTS. In order to accommodate the
foregoing changes, the following modifications will be made to the procedures
set forth in EXHIBIT "C" of the Lease regarding the Interior Improvements:

          a.   The entire 37,800 sq. ft. building will be finished out at a
     minimum $18.000 per square foot level of finish, or as may be subsequently
     agreed to in writing between Landlord and Tenant on or before November 30,
     1998.

          b.   The portion of the Premises to be occupied by Tenant may be
     finished out at a level which is higher than the $18.00 per square foot
     minimum level provided that the Excess (as such term is defined in SECTION
     5b of EXHIBIT "C" attached to the Lease) shall be deposited by Tenant into
     the Escrow Account (as such term is defined in SECTION 5b of EXHIBIT "C"
     attached to the Lease) on or before January 4, 1999.

          c.   Any portion of the Premises not to be initially occupied by
     Tenant may be finished out on behalf of a subtenant at a level which is
     higher than the $18.00 per square foot minimum level provided that the
     Excess related to such portion of the Premises shall also be deposited by
     Tenant into the Escrow Account on or before January 4, 1999.

     11.  DELETION OF EXPANSION OPTION. The Expansion Option [as such term is
defined in that certain Right of First Refusal and Option Agreement (the "RIGHT
OF FIRST REFUSAL AND OPTION AGREEMENT") dated of even date with the Lease and
executed by Landlord, Tenant and 290 Office Building, Ltd. regarding space in
the office building located 5613 Highway 290 West, Austin, Texas], is hereby
deleted in its entirety, is null, void and of no further force or effect, as
fully as if the Expansion Option had never been granted in the first place.

     12.  SUSPENSION OF RIGHT OF FIRST REFUSAL. The Rights of First Refusal
granted to Tenant in the Right of First Refusal and Option Agreement are hereby
suspended until January

                                  Page 3 of 5

<PAGE>

4, 1999. Accordingly, the Office Building Owner is free to lease any and all of
the space in the Office Building to any party whatsoever without the obligation
to offer any part thereof to Tenant through January 3, 1999, at which time
Tenant's rights to the Rights of First Refusal, if any, will be deemed to be
revived, but only to the extent provided in the Right of First Refusal and
Option Agreement and only as to space leased after January 3, 1999.

     13.  AMENDMENT TO SECTION 28 OF THE LEASE. SECTION 28 of the Lease is
hereby deleted in its entirety and is replaced with the following:

     "Notwithstanding anything contained in this Lease to the contrary,
     Landlord's obligations hereunder are specifically conditioned upon Landlord
     achieving substantial completion of the Premises not later than June 30,
     1999, subject to any extensions for force majeure and delays caused by
     Tenant (not including the suspension of the commencement of construction of
     the Interior Improvements until January 4, 1999). In the event Landlord
     does not achieve substantial completion of the Premises by June 30, 1999,
     Tenant, as Tenant's sole and exclusive remedy, may terminate this Lease in
     writing at any time after June 30, 1999 and before Landlord achieves
     substantial completion of the Premises. In the event Tenant terminates this
     Lease pursuant to this paragraph, Landlord will return all advance payments
     of rent and Security Deposits theretofore paid to Landlord by Tenant and
     all Letters of Credit theretofore delivered to Landlord by Tenant and will
     reimburse and refund Tenant for all moneys theretofore expended by Tenant
     in connection with the construction of the Interior Improvements pursuant
     to paragraph 5b of EXHIBIT "C" attached hereto, as well as any moneys
     remaining in the escrow account for Tenant's Proportionate Share of the
     cost of the Interior Improvements."

     14.  CAPITALIZED TERMS. All capitalized terms used herein shall have the
meaning ascribed to them in the Lease unless specifically defined herein.

     15.  EFFECT OF AMENDMENT. The Lease and the Ancillary Agreements (as
defined in the First Amendment), as hereby amended, shall continue in full force
and effect. All of the other terms of the Lease and the Ancillary Agreements
shall remain unchanged and shall continue in full force and effect.

     16.  COUNTERPARTS. This Second Amendment may be executed in several
counterparts and all counterparts so executed shall together be deemed to
constitute one final agreement as if signed by all parties hereto and all
counterparts shall be deemed to be an original.

     17.  AMENDMENT CONTROLLING. The provisions of this Second Amendment shall
supersede and control over any conflicting provisions in the Lease and the
Ancillary Agreements.

                                  Page 4 of 5
<PAGE>

        EXECUTED to be effective as of the date first above written.

                                       LANDLORD:

                                       S.W. AUSTIN OFFICE BUILDING, LTD., A
                                       TEXAS LIMITED PARTNERSHIP

                                       By: /s/ Manuel Zuniga
                                          ---------------------------------
                                       Name:  MANUEL ZUNIGA
                                            -------------------------------
                                       Title:  PARTNER
                                             ------------------------------

                                       TENANT:

                                       SILICON LABORATORIES, INC., A DELAWARE
                                       CORPORATION

                                       By: /s/ Navdeep Sooch
                                          ---------------------------------
                                       Name:  NAVDEEP SOOCH
                                            -------------------------------
                                       Title:  PRESIDENT
                                             ------------------------------

EXECUTED by the undersigned for purposes of Paragraph 5, above.

                                       OXFORD COMMERCIAL, INC., A TEXAS
                                       CORPORATION

                                       By: /s/ Michael K. Tipps
                                          ---------------------------------
                                       Name:  Michael K. Tipps
                                            -------------------------------
                                       Title:  Managing Principal
                                             ------------------------------

                                  Page 5 of 5<PAGE>

                                 LEASE AGREEMENT

                                     Between

                         STRATUS 7000 WEST JOINT VENTURE

                                  as Landlord,

                                       and

                            SILICON LABORATORIES INC.

                                   as Tenant,

               Covering approximately 34,531 rentable square feet
                    of the Building known (or to be known) as

                        7000 West at Lantana, Building 1

                                   located at

                         7000 West William Cannon Drive

                               Austin, Texas 78735

<PAGE>

                            BASIC LEASE INFORMATION

<TABLE>
<S>                      <C>
Lease Date:              October 27, 1999

Tenant:                  Silicon Laboratories Inc.

Tenant's Address:        4635 Boston Lane
                         ---------------------------
                         Austin Texas 78735
                         ---------------------------

                         ---------------------------

                         ---------------------------

Contact:                 John McGovern

Telephone:               (512) 416-8500
                         ---------------------------

Landlord:                Stratus 7000 West Joint Venture

Landlord's
Address:                 c/o Stratus Management, L.L.C.
                         98 San Jacinto, Suite 220
                         Austin, Texas 78701

Contact:                 Rick Lindley

Telephone:               478-5788

Premises:                Suite No. ____ containing approximately 34,531 rentable
                         square feet on the second floor of the Building. The
                         Premises are outlined on the plan attached to the Lease
                         as EXHIBIT A-1. The Premises are measured using 1996
                         BOMA useable standards multiplied by the Building
                         Factor of 1.0881.

Building:                7000 West at Lantana Building 1, which contains
                         66,606 of rentable square feet and is located or to be
                         located on the land described on EXHIBIT A attached
                         hereto (the "LAND").

Project:                 7000 West at Lantana, which includes the Building,
                         one (1) other office building known (or if not yet
                         constructed, to be known) as Building 2 and related
                         parking facilities and commons areas, as shown on
                         EXHIBIT A-2 attached hereto.

Development:             All improvements within the Project plus all other
                         improvements owned by Landlord and Landlord's
                         affiliates in an area in the Lantana Corporate Center
                         bounded by William Cannon Drive West on the west,
                         Southwest Parkway on the north, and Vega running on the
                         southern boundary.

Term:                    Seventy-six (76) months, commencing the later of: i)
                         February 1, 2000 or ii) the date upon which the Work
                         improvements set forth in EXHIBIT D have been
                         Substantially Completed (the "Commencement Date") and
                         ending at 5:00 p.m., May 31, 2006, subject to
                         adjustment based on the date of Substantial Completion
                         and earlier termination as provided in the Lease.

Substantial Completion:  The term "Substantially Completed" or "Substantial
                         Completion" shall mean that, in the opinion of the
                         architect and space planner that prepared the Working
                         Drawings, such Work has been substantially completed in
                         accordance with the Working Drawings, the Premises are
                         in good and satisfactory condition, with the exception
                         of completion of minor details of construction,
                         mechanical adjustments or decorations which do not
                         materially interfere with Tenant's use of the Premises
                         that remain to be performed (items normally referred to
                         as "punch list" items), and the City of Austin has
                         issued a certificate of occupancy for the Premises;
                         provided, however, that if and to the extent
                         Substantial Completion would have occurred earlier but
                         for any Tenant Delays (as defined in Exhibit D),
                         Substantial Completion shall be deemed to have occurred
                         on the date it would have occurred but for those Tenant
                         Delays.

                                       i
<PAGE>

Basic Rental:            (i) for month 1-6, $22,301.27 per month, which is based
                         on an Annual Basic Rental of $15.50 per rentable square
                         foot, but only on 17,265.5 square feet (1/2 of the
                         Premises) (i.e., the rent on 1/2 of the Premises is
                         being abated for six months); provided, however, that,
                         during months 1-6, Tenant shall pay Basic Rent to
                         Landlord for any space occupied by Tenant for office
                         use (as contrasted to storage) over and above 17,265.5
                         square feet on a per diem basis at a rate of $15.50 per
                         rentable square foot/year; (ii) for months 7-24,
                         $44,602.54 per month, which is based on an annual Basic
                         Rental of $15.50 per rentable square foot on the full
                         34,531 square feet; (iii) for months 25-48, $47,480.12
                         per month, which is based on an annual Basic Rental of
                         $16.50 per rentable square foot and (iv) for months
                         49-76, $48,918.92 per month, which is based on an
                         annual Basic Rental of $17.00 per rentable square foot.

Security Deposit:        $64,745.62 in cash and the Letter of Credit (as defined
                         in Section 6)

Rent:                    Basic Rental, Tenant's Proportionate Share of Basic
                         Costs and all other sums that Tenant may owe to
                         Landlord under the Lease.

Permitted Use:           General office use including ancillary uses related to
                         general office use, including the operation of vending
                         machines within the Premises for use by Tenant's
                         employees and visitors.

Tenant's
Proportionate
Share:                   51.84%, which is the percentage obtained by dividing
                         (a) the 34,531 rentable square feet in the Premises by
                         (b) the 66,606 rentable square feet in the Building.

Tenant's Estimated
Proportionate Share
of Basic Costs:          Costs of $7.00 per rentable square foot ($20,143.08 per
                         month) beginning on the Commencement Date and on the
                         first day of each calendar month thereafter through
                         December 31, 2000; provided, however, that Tenant's
                         Estimated Proportionate Share of Basic Costs shall be
                         abated as to 17,265.5 square feet out of the total
                         34,531 square feet within the Premises for months 1-6
                         (I.E., the estimated amount of Tenant's Proportionate
                         Share of Basic Costs for months 1-6 of the Lease is
                         $10,071.54 per month). Notwithstanding the foregoing,
                         during months 1-6, Tenant shall pay Tenant's Estimated
                         Proportionate Share of Basic Costs to Landlord for any
                         space occupied by Tenant over and above 17,265.5 square
                         feet on a per diem basis billed monthly in arrears at a
                         rate of $7.00 per rentable square foot/year.
                         Furthermore, the abatements provided for in this
                         paragraph shall apply to utilities, as described in
                         paragraph 4 of Exhibit C attached hereto, so long as
                         the HVAC system, lighting (except basic and emergency
                         lighting) and all office machinery and equipment is
                         operated during the abatement period only in that
                         certain approximately 17,265.5 square feet of the
                         Premises shown on Exhibit A-1 attached hereto as the
                         "Initial Space". If the HVAC system, lighting (except
                         basic and emergency lighting) or any office machinery
                         or equipment is operated in portions of the Premises
                         other than the Initial Space during months 1-6, Tenant
                         shall pay Tenant's Estimated Proportionate Share of the
                         utility portion of Basic Costs to Landlord for all of
                         the Premises on a per diem basis billed monthly in
                         arrears. Beginning on January 1, 2001 and thereafter,
                         the costs shall be paid by Tenant as set forth in
                         Section 4(c) of the Lease.
Initial
Liability
Insurance Amount:        $3,000,000.00

Maximum
Construction
Allowance:               $24.00 per rentable square foot

Building's
Proportionate
Share:                   The percentage obtained by dividing (a) the 66,606
                         rentable square feet contained within Building by (b)
                         the number of completed rentable square feet contained
                         within the Project; provided that Landlord and Tenant
                         acknowledge that the Building's Proportionate Share be
                         adjusted as additional completed rentable square feet
                         are added to or subtracted from the Project. Currently,
                         the Building's Proportionate Share equals 100%.
</TABLE>

                                       ii
<PAGE>

The foregoing Basic Lease Information is incorporated into and made a part of
the Lease identified above. If any conflict exists between any Basic Lease
Information and the Lease, then the Lease shall control.

                       LANDLORD:  STRATUS 7000 WEST JOINT VENTURE
                                  a Texas joint venture

                             By:  OLY LANTANA, L.P., a Texas limited
                                  partnership, Joint Venturer

                                  By:  OLY LANTANA, GP, L.L.C., a Texas limted
                                       liability company, its General Partner

                                       By: /s/ Hal R. Hall
                                          ------------------------------
                                       Name:
                                             ---------------------------
                                       Title:
                                             ---------------------------

                             By:  STRATUS 7000 WEST, LTD., a Texas limited
                                  partnership, Joint Venturer

                                  By:  STRS, L.L.C., a Delaware limited
                                       liability company, its General Partner

                                       By:  STRATUS PROPERTIES INC., a Delaware
                                            limited liability company, its
                                            sole member

                                            By: /s/ William H. Armstrong
                                               ------------------------------
                                                William H. Armstrong, III
                                                President and CEO

                       TENANT: SILICON LABORATORIES INC.

                             By: /s/ Navdeep S. Sooch
                                -----------------------------
                                Navdeep S. Sooch
                                Chairman and CEO

                                       iii
<PAGE>

                               TABLE OF CONTENTS
<TABLE>
<CAPTION>
                                                                      Page
                                                                      ----
<S>                                                                    <C>
DEFINITIONS AND BASIC PROVISIONS.......................................  1

LEASE GRANT............................................................  1

TERM...................................................................  1

RENT...................................................................  1
        (a)  Payment...................................................  1
        (b)  Consumer Price Index Increases to Basic Rental............  1
        (c)  Basic Costs...............................................  1
        (d)  Annual Cost Statement.....................................  1
        (e)  Restoration of Services; Abatement........................  2

DELINQUENT PAYMENT; HANDLING CHARGES...................................  2

SECURITY DEPOSIT.......................................................  2

LANDLORD'S OBLIGATIONS.................................................  3
        (a)  Services..................................................  3
        (b)  Excess Utility Use........................................  3
        (c)  Discontinuance............................................  4
        (d)  Adjustments to Basic Costs................................  4

IMPROVEMENTS; ALTERATIONS; REPAIRS; MAINTENANCE........................  4
        (a)  Improvements; Alterations.................................  4
        (b)  Repairs; Maintenance......................................  4
        (c)  Performance of Work.......................................  5
        (d)  Mechanic's Liens..........................................  5

USE....................................................................  5

ASSIGNMENT AND SUBLETTING..............................................  5
        (a)  Transfers; Consent........................................  5
        (b)  Cancellation..............................................  6
        (c)  Additional Compensation...................................  6

INSURANCE; WAIVERS; SUBROGATION; INDEMNITY.............................  6
        (a)  Tenant's Insurance........................................  6
        (b)  Landlord's Insurance......................................  6
        (d)  Waiver of Negligence Claims; No Subrogation...............  7
        (e)  Indemnity.................................................  7

SUBORDINATION ATTORNMENT; NOTICE TO LANDLORD'S MORTGAGEE...............  7
        (a)  Subordination.............................................  7
        (b)  Attornment................................................  7
        (c)  Notice to Landlord's Mortgagee............................  7

RULES AND REGULATIONS..................................................  7

CONDEMNATION...........................................................  7
        (a)  Taking - Landlord's and Tenant's Right....................  7
        (b)  Taking - Landlord's Rights................................  8
        (c)  Award.....................................................  8

FIRE OR OTHER CASUALTY.................................................  8
        (a)  Repair Estimate...........................................  8
        (b)  Landlord's and Tenant's Rights............................  8
        (c)  Landlord's Rights.........................................  8
        (d)  Repair Obligation.........................................  8

TAXES..................................................................  8

EVENTS OF DEFAULT......................................................  8

REMEDIES...............................................................  9

                                       iv
<PAGE>

PAYMENT BY TENANT; NON-WAIVER..........................................  9
        (a)  Payment by Tenant......................................... 10
        (b)  No Waiver................................................. 10

SURRENDER OF PREMISES.................................................. 10

HOLDING OVER........................................................... 10

CERTAIN RIGHTS RESERVED BY LANDLORD.................................... 10

SUBSTITUTION SPACE..................................................... 10

MISCELLANEOUS.......................................................... 11
        (a)  Landlord Transfer......................................... 11
        (b)  Landlord's Liability...................................... 11
        (c)  Force Majeure............................................. 11
        (d)  Brokerage................................................. 11
        (e)  Estoppel Certificates..................................... 11
        (f)  Notices................................................... 11
        (g)  Separability.............................................. 11
        (h)  Amendments; and Binding Effect............................ 11
        (i)  Quiet Enjoyment........................................... 11
        (j)  Joint and Several Liability............................... 11
        (k)  Captions.................................................. 11
        (l)  No Merger................................................. 11
        (m)  No Offer.................................................. 12
        (n)  Exhibits.................................................. 12
        (o)  Entire Agreement.......................................... 12

HAZARDOUS SUBSTANCES................................................... 12

LANDLORD'S LIEN........................................................ 13

SPECIAL PROVISIONS..................................................... 13
</TABLE>

                                       v
<PAGE>

                            LIST OF DEFINED TERMS

<TABLE>
<CAPTION>
                                                             Page
                                                              No.
<S>                                                          <C>
Affiliate...................................................   6
Annual Cost Statement.......................................   1
Basic Cost.................................................. C-1
Basic Lease Information.....................................   1
Building....................................................   i
Casualty....................................................   8
Commencement Date...........................................   i
Construction Allowance...................................... D-2
Damage Notice...............................................   8
Development.................................................   i
Event of Default............................................   8
Initial Liability Insurance Amount..........................   6
Land........................................................   i
Landlord....................................................   1
Landlord's Mortgagee........................................   7
Lease.......................................................   1
Loss........................................................   6
Mortgage....................................................   7
Parking Facilities.......................................... E-1
Primary Lease...............................................   7
Taking......................................................   7
Taxes....................................................... C-1
Tenant......................................................   1
Tenant Delay................................................ D-1
Total Construction Costs.................................... D-1
Transfer....................................................   5
Work........................................................ D-1
Working Drawings............................................ D-1

</TABLE>

                                       vi
<PAGE>

                                      LEASE

THIS LEASE AGREEMENT (this "LEASE") is entered into as of OCTOBER 27 1999,
between Stratus 7000 West Joint Venture,  a Texas joint venture ("LANDLORD"),
and Silicon Laboratories, Inc. (TENANT").

DEFINITIONS
AND BASIC
PROVISIONS

               1.   The definitions and basic provision set forth in the Basic
          Lease Information (the "BASIC LEASE INFORMATION") executed by Landlord
          and Tenant contemporaneously herewith are incorporated herein by
          reference for all purposes.

LEASE
GRANT          2.   Subject to the terms of this Lease, Landlord leases to
          Tenant, and Tenant leases from Landlord, the Premises.

TERM           3.   If the Commencement Date is not the first day of a calendar
          month, then the Term shall be extended by the time between the
          Commencement Date and the first day of the next month. If this Lease
          is executed before the Premises become available and ready for
          occupancy by Tenant, then (a) Tenant's obligation to pay Rent
          hereunder shall be waived until Landlord tenders possession of the
          Premises to Tenant, (b) the Term shall be extended by the time between
          the scheduled Commencement Date and the date on which Landlord tenders
          possession of the Premises to Tenant (which date will then be defined
          as the Commencement Date), (c) Landlord shall not be in default
          hereunder or be liable for damages therefor, and (d) Tenant shall
          accept possession of the Premises when Landlord tenders possession
          thereof to Tenant. By occupying the Premises, Tenant shall be deemed
          to have accepted the Premises in their condition as of the date of
          such occupancy, subject to the performance of punch-list items that
          remain to be performed by Landlord, if any. Tenant shall execute and
          deliver to Landlord, within ten days after Landlord has requested
          same, a letter confirming (1) the Commencement Date, (2) that Tenant
          has accepted the Premises, and (3) that Landlord has performed all of
          its obligations with respect to the Premises (except for punch-list
          items specified in such letter).

RENT           4.   (a)  PAYMENT. Tenant shall timely pay to Landlord the Basic
          Rental and all additional sums to be paid by Tenant to Landlord under
          this Lease, including the amounts set forth in EXHIBIT C, without
          deduction or set off except as otherwise expressly provided in Section
          7(d), at Landlord's Address (or such other address as Landlord may
          from time to time designate in writing to Tenant). Basic Rental,
          adjusted as herein provided, shall be payable monthly in advance. The
          first monthly installment of Basic Rental shall be payable upon the
          Commencement Date of this Lease; thereafter, monthly installments of
          Basic Rental shall be due on the first day of the second full calendar
          month of the Term and continuing on the first day of each succeeding
          calendar month during the Term. Basic Rental for any fractional month
          at the beginning of the Term shall be prorated based on 1/365 of the
          current annual Basic Rental for each day of the partial month this
          Lease is in effect, and shall be due on the Commencement Date.

               (b)  CONSUMER PRICE INDEX INCREASES TO BASIC RENTAL.
          (Intentionally Omitted.)

               (c)  BASIC COSTS. Beginning on January 1, 2001 and thereafter,
          Tenant shall pay to Landlord, on the first day of each calendar month,
          an amount equal to the product of (1) 1/12 of the estimated Basic
          Costs (as described on EXHIBIT C), multiplied by (2) Tenant's
          Proportionate Share. From time to time during any calendar year after
          calendar year 2000, Landlord may in good faith estimate and
          re-estimate the Proportionate Share of Basic Costs to be due by Tenant
          for that calendar year and deliver a copy of the estimate or
          re-estimate to Tenant. Thereafter, the monthly installments of
          estimated Basic Costs payable by Tenant shall be appropriately
          adjusted in accordance with the estimations so that, by the end of the
          calendar year in question, Tenant shall have paid all of its
          Proportionate Share of Basic Costs as estimated in good faith by
          Landlord.

               (d)  ANNUAL COST STATEMENT. By April 1 of each calendar year, or
          as soon thereafter as practicable, Landlord shall furnish to Tenant a
          statement of Landlord's actual Basic Costs (the "ANNUAL COST
          STATEMENT") for the previous year (including calendar year 2000)
          adjusted as provided in Section 4.(e). If the Annual Cost Statement
          reveals that Tenant paid more for Basic Costs than

                                       1
<PAGE>

          Tenant's Proportionate Share of Basic Costs in the year for which such
          statement was prepared, then Landlord shall credit Tenant for such
          excess during the following year; likewise, if Tenant paid less than
          Tenant's Proportionate Share of Basic Costs, then Tenant shall pay
          Landlord such deficiency within 30 days after delivery of the Annual
          Cost Statement in question; provided, however, that in no event shall
          Tenant's Proportionate Share of Basic Costs in any year (commencing
          with calendar year 2001) exceed the immediately preceding year's
          Proportionate Share of Basic Costs by more than six percent (6%) of
          such preceding year's Proportionate Share of Basic Costs, excluding
          Tenant's Proportionate Share of Basic Costs for insurance, taxes and
          utilities (none of which shall be subject to such yearly six percent
          (6%) maximum increase). Notwithstanding the foregoing, it is hereby
          acknowledged that the 6% cap on controllable Basic Costs shall be
          calculated on a cumulative basis (i.e., if the increase in costs in
          any given year is less than 6% then the difference between the actual
          percentage increase and 6% may be carried over to be used in
          subsequent years in which the increase exceeds 6%). Further, the
          parties acknowledge that for purposes of calculating the cap on Basic
          Costs in calendar year 2001, adjustments shall be made (subject to the
          limitations in Section 4(e) below) in order to reflect any abatements
          of the Basic Costs granted to Tenant for calendar year 2000, as
          provided in the Basic Lease Information.

               (e)  ADJUSTMENTS TO BASIC COSTS. With respect to any calendar
          year or partial calendar year in which the Building is not occupied to
          the extent of 95% of the rentable area thereof, the Basic Costs for
          such period shall, for the purposes hereof, be increased to the amount
          which would have been incurred had the Building been occupied to the
          extent of 95% of the rentable area thereof.

               (f)  AUDIT RIGHTS. Tenant and its agents shall have the right,
          upon ten (10) days' written notice, to audit, inspect and copy the
          books and records relating to the Basic Costs during normal business
          hours. If any audit shall accurately reflect a discrepancy between the
          actual Basic Costs and the amount shown on any Annual Cost Statement
          previously furnished Tenant, the parties shall reconcile the
          discrepancy. Tenant shall not be permitted to audit periods earlier
          than the immediately preceding two (2) years.

DELINQUENT
PAYMENT;
HANDLING
CHARGES        5.   All payments required of Tenant hereunder shall bear
          interest from the date due until paid at the maximum lawful rate.
          Alternatively, Landlord may charge Tenant a fee equal to 5% of the
          delinquent payment to reimburse Landlord for its cost and
          inconvenience incurred as a consequence of Tenant's delinquency. In no
          event, however, shall the charges permitted under this Section 5 or
          elsewhere in this Lease, to the extent the same are considered to be
          interest under applicable law, exceed the maximum lawful rate of
          interest. The interest and the 5% fee referenced in this Section 5
          shall begin to accrue and only be payable by Tenant on the tenth
          (10th) day following written notice from Landlord notifying Tenant of
          Tenant's delinquency; provided, however, that in the event Landlord
          gives to Tenant notice of Tenant's delinquency two (2) times in any
          calendar year, the interest and the 5% fee referenced in this Section
          5 shall begin to accrue and be payable by Tenant immediately (without
          notice) upon Tenant's third (3rd) delinquency (and any subsequent
          delinquencies) in such calendar year.

SECURITY
DEPOSIT        6.   Contemporaneously with the execution of this Lease, Tenant
          shall pay to Landlord, in immediately available funds, the Security
          Deposit, which shall be held by Landlord without liability for
          interest and as security for the performance by Tenant of its
          obligations under this Lease. The Security Deposit is not an advance
          payment of Rent or a measure or limit of Landlord's damages upon an
          Event of Default (defined below). Landlord may, from time to time and
          without prejudice to any other remedy, use all or a part of the
          Security Deposit upon and after an Event of Default to perform any
          obligation which Tenant was obligated, but failed, to perform
          hereunder. Following any such application of the Security Deposit,
          Tenant shall pay to Landlord on demand the amount so applied in order
          to restore the Security Deposit to its original amount. Within a
          reasonable time after the Term ends, provided Tenant has performed all
          of its obligations hereunder, Landlord shall return to Tenant the
          balance of the Security Deposit not applied to satisfy Tenant's
          obligations. If Landlord transfers its interest in the Premises, then
          Landlord shall assign the Security Deposit to the transferee and
          Landlord thereafter shall have no further liability for the return of
          the Security Deposit.

          In addition to the cash Security Deposit above, Tenant shall deposit
          with Landlord on or before the thirtieth (30th) day after the date
          hereof, either additional cash or irrevocable stand-by letter(s) of
          credit in the amount of $500,000.00 (whether one or more, the "LETTER
          OF CREDIT"), which shall be held and/or applied by Landlord in
          accordance with this Section 6; however, the Letter of Credit is not
          an advance rental deposit or a measure of Landlord's damages for an
          Event of Default (defined below). The Letter of Credit shall be

                                       2
<PAGE>

          issued by a bank reasonably acceptable to Landlord and shall otherwise
          be in such form and contain such terms as are reasonably acceptable to
          Landlord. The Letter of Credit will be structured as successive one-
          year obligations for the entire term with rights to draw on the Letter
          of Credit of a substitute letter of credit of the proper amount is not
          in place within twenty (20) business days before expiration of the
          Letter of Credit. Landlord hereby approves Imperial Bank as the
          acceptable provider of the Letter of Credit in such form and terms set
          forth in EXHIBIT I "Letter of Credit Pro Form Wording." The amount of
          the Letter of Credit shall be decreased by 16.67% on each anniversary
          of the Commencement Date, so long as no Event of Default exists. Upon
          an Event of Default, Landlord may, in addition to all other rights and
          remedies afforded Landlord hereunder or by law, cash the Letter of
          Credit (as the same may have been reduced) and notify Tenant of such
          action and use and hold the same as a cash security deposit, which
          shall include the right to use any portion thereof to satisfy Tenant's
          unperformed obligations hereunder, without prejudice to any of
          Landlord's other remedies. If so used, Tenant shall pay Landlord an
          amount that will restore the Letter of Credit to its then amortized
          balance upon request. The Letter of Credit will be returned to Tenant
          within 30 days after the end of the Term, provided that Tenant has
          fully and timely performed its obligations hereunder throughout the
          Term. If Landlord sells its interest in the Building, the Letter of
          Credit shall be transferred to such purchaser, and Tenant hereby
          agrees to cooperate in effectuating any such transfer. Notwithstanding
          the foregoing, the Letter of Credit shall be returned to Tenant, so
          long as no Event of Default exists, if either of the following shall
          occur: (1) if Tenant is a privately owned company, an audited
          financial statement is provided to Landlord showing twelve (12)
          consecutive months' aggregate revenues in excess of $80,000,000.00 and
          an aggregate net operating income in excess of $8,000,000.00 for such
          12 consecutive months; or (2) if Tenant is a publicly owned company,
          Securities and Exchange Commission filings containing financial
          statements are provided to Landlord showing four quarters' aggregate
          revenues in excess of $80,000,000.00 and a net operating income in
          excess of $8,000,000.00 (such period may include unaudited quarterly
          periods provided that they are filed with the Securities and Exchange
          Commission).

LANDLORD'S
OBLIGATIONS

               7.   (a)  SERVICES. Provided no Event of Default exists, Landlord
          shall furnish to Tenant (1) water (hot and cold) at those points of
          supply provided for general use of tenants of the Building; (2) heated
          and refrigerated air conditioning as appropriate, during normal
          business hours, and at such temperatures and in such amounts as are
          reasonably considered by Landlord to be standard; (3) janitorial
          service, in compliance with Tenant's confidential and proprietary
          procedures, to the Premises on weekdays other than holidays for
          Building-standard installations (Landlord reserves the right to bill
          Tenant separately for extra janitorial service required for
          non-standard installations) and such window washing as may from time
          to time in Landlord's judgment be reasonably required; provided,
          however, that Landlord, at its option, may decide to cease providing
          janitorial service to the Premises, in which event Tenant will be
          responsible for providing its own janitorial service and Tenant's
          Proportionate share of Basic Costs shall be equitably reduced to
          reflect the same; (4) elevators for ingress and egress to the floor on
          which the Premises are located, in common with other tenants, provided
          that Landlord may reasonably limit the number of elevators to be in
          operation at times other than during customary business hours and on
          holidays; (5) replacement of Building-standard light bulbs and
          fluorescent tubes; and (6) electrical current during normal business
          hours at a power capacity of 4 watts per rentable space foot for
          lighting and outlets ("Normal Usage"). Landlord shall maintain the
          common areas of the Building in reasonably good order and condition,
          except for damage occasioned by Tenant, or its employees, agents or
          invitees. If Tenant desires any of the services specified in this
          Section 7.(a) at any time other than times herein designated, such
          services shall be supplied to Tenant upon the written request of
          Tenant delivered to Landlord before 3:00 p.m. on the business day
          preceding such extra usage (except for heated and refrigerated air
          conditioning, which shall be immediately available to Tenant through
          use of an automated "on-demand" system to be installed by Landlord or,
          in the event such automated "on-demand" system is not available due to
          system failure, immediately provided by Landlord upon verbal request
          from Tenant, so long as such request is made during normal business
          hours), and Tenant shall pay to Landlord the cost of such services,
          which shall be provided at the same rate charged other tenants in the
          Building, within ten days after Landlord has delivered to Tenant an
          invoice therefor. As used herein, the term "normal business hours"
          shall mean from 7:00 a.m. to 7:00 p.m. Monday through Friday and from
          8:00 a.m. to 1:00 p.m. on Saturdays, except for legal holidays. Based
          on a letter from Southwestern Bell, Landlord has confirmed fiber
          optics are to be provided to a point adjacent to the outside of the
          Building or at the telecommunications building at the northwest corner
          of Rialto and William Cannon. The provider of such fiber optics shall
          be Southwestern Bell. Tenant, if it so desires at Tenant's cost, shall
          be responsible and Landlord grants all consents for obtaining fiber
          optics telecommunications service to the Premises from a point
          adjacent to the outside of the building or the telecommunication
          building (without additional rent for using risers or feeder space or
          otherwise); provided that in doing so Tenant shall not adversely
          affect the Building or Building systems or interfere with other
          tenants or building operations; and provided further that, Landlord
          has or will designate the Building as a multi-tenant building with
          Southwestern Bell, thereby making the Premises the point of
          demarcation for Tenant's fiber optics service.

               (b)  EXCESS UTILITY USE. Landlord shall use reasonable efforts
          to furnish electrical current for special lighting, computers and
          other equipment whose electrical energy consumption exceeds Normal
          Usage through the then-existing feeders and risers serving the
          Building and the Premises (not to exceed, however, 6.5 watts per
          rentable square foot), and Tenant shall pay to Landlord the cost of
          such service within ten days after Landlord has delivered to Tenant an
          invoice therefor. Landlord may determine the amount of such additional

                                       3
<PAGE>

          consumption and potential consumption by either or both: (1) a survey
          of standard or average tenant usage of electricity in the Building
          performed by a reputable consultant selected by Landlord and paid for
          by Tenant; or (2) a separate meter in the Premises installed,
          maintained, and read by Landlord, at Tenant's expense. Tenant shall
          not install any electrical equipment requiring special wiring or
          requiring electrical current in excess of Normal Usage unless approved
          in advance by Landlord. The use of electricity in the Premises shall
          not exceed the capacity of existing feeders and risers to or wiring in
          the Premises. Any risers or wiring required to meet Tenant's excess
          electrical requirements shall, upon Tenant's written request, be
          installed by Landlord, at Tenant's cost, if, in Landlord's sole and
          absolute judgment, the same are necessary and shall not cause
          permanent damage or injury to the Building or the Premises, cause or
          create a dangerous or hazardous condition, entail excessive or
          unreasonable alterations, repairs, or expenses, or interfere with or
          disturb other tenants of the Building. If Tenant uses machines or
          equipment (other than general office machines, personal computers and
          electronic data processing equipment) in the Premises which affect the
          temperature otherwise maintained by the air conditioning system or
          otherwise overload any utility, Landlord may install supplemental air
          conditioning units or other supplemental equipment in the Premises,
          and the cost thereof, including the cost of installation, operation,
          use, and maintenance, shall be paid by Tenant to Landlord within ten
          days after Landlord has delivered to Tenant an invoice therefor.

               (c)  DISCONTINUANCE. Landlord's obligation to furnish services
          under Section 7.(a) shall be subject to the rules and regulations of
          the supplier of such services and governmental rules and regulations.
          Landlord may, upon not less than 30-days' prior written notice to
          Tenant, discontinue any such service to the Premises, provided
          Landlord first arranges for a fully functioning, equivalent capacity
          direct connection thereof through the supplier of such service. Tenant
          shall, however, be responsible for contracting with the supplier of
          such service and for paying all deposits for, and costs relating to,
          such service.

               (d)  RESTORATION OF SERVICES; ABATEMENT. Landlord shall use
          reasonable efforts to restore any service that becomes unavailable;
          however, such unavailability shall (i) not render Landlord liable for
          any damages caused thereby, (ii) be a constructive eviction of Tenant,
          (iii) constitute a breach of any implied warranty, or, except as
          provided in the next sentence, or (iv) entitle Tenant to any abatement
          of Tenant's obligations hereunder. However, if Tenant is prevented
          from making reasonable use of the Premises for more than 15
          consecutive days (or 5 consecutive days if the reason for such
          unavailability is within the reasonable control of Landlord) because
          of the unavailability of any such service, Tenant shall, as its
          exclusive remedy therefor, be entitled to a reasonable abatement of
          Rent for each consecutive day (after such 15-day or 5-day period, as
          applicable) that Tenant is so prevented from making reasonable use of
          the Premises. Notwithstanding the foregoing, Tenant has the right to
          terminate the Lease effective sixty (60) days after Tenant notifies
          Landlord in writing of a material utility service (not including fiber
          optics) discontinuance, unless such utility service is restored within
          such 60-day period.

               8.   (a)  IMPROVEMENTS: ALTERATIONS. Improvements to the Premises
          shall be installed at the expense of Tenant only in accordance with
          plans and specifications which have been previously submitted to and
          approved in writing by Landlord. After the initial Tenant improvements
          are made, no alterations or physical additions in or to the Premises
          may be made without Landlord's prior written consent. Tenant shall not
          paint or install lighting or decorations, signs, window or door
          lettering, or advertising media of any type on or about the Premises
          without the prior written consent of Landlord. All alterations,
          additions, or improvements (whether temporary or permanent in
          character, and including without limitation all air-conditioning
          equipment and all other equipment that is in any manner connected to
          the Building's plumbing system) made in or upon the Premises, either
          by Landlord or Tenant, shall be Landlord's property at the end of the
          Term and shall remain on the premises without compensation to Tenant.
          Approval by Landlord of any of Tenant's drawings and plans and
          specifications prepared in connection with any improvements in the
          Premises shall not constitute a representation or warranty of Landlord
          as to the adequacy or sufficiency of such drawings, plans and
          specifications, or the improvements to which they relate, for any use,
          purpose, or condition, but such approval shall merely be the consent
          of Landlord as required hereunder. Notwithstanding anything in this
          Lease to the contrary, Tenant shall be responsible for the cost of all
          work within the Premises required to comply with the retrofit
          requirements of the Americans with Disabilities Act of 1990, and all
          rules, regulations, and guidelines promulgated thereunder, as the same
          may be amended from time to time (the "ADA"), necessitated by any
          installations, additions, or alterations made in or to the Premises at
          the request of or by Tenant or by Tenant's use of the Premises (other
          than retrofit work whose cost has been particularly identified as
          being payable by Landlord in an instrument signed by Landlord and
          Tenant), and Landlord shall be responsible for the cost of all work
          required to comply with the ADA in connection with other areas of the
          Building. Notwithstanding the foregoing, all moveable partitions,
          cubical furniture and de-mountable wall systems are to be considered
          personal property of the Tenant (similar to furniture) and may be
          erected, moved, re-configured and removed, including minor electrical
          connections, without consent from Landlord provided that the Building
          is returned to its original or otherwise satisfactory condition after
          such removal.

               (b). REPAIRS; MAINTENANCE. Tenant shall maintain the Premises in
          a clean, safe, operable, attractive condition, and shall not permit or
          allow to remain any waste or damage to any portion of the Premises.
          Tenant shall repair or replace, subject to Landlord's direction and
          supervision any damage to the Building caused by Tenant or Tenant's
          agents, contractors, or invitees. If Tenant fails to make such repairs
          or replacements within 15 days after the occurrence of such damage,
          then Landlord may make the same at Tenant's cost. In lieu of having
          Tenant repair any such damage outside of the Premises, Landlord may
          repair

                                       4
<PAGE>

          such damage at Tenant's cost. The cost of any repair or replacement
          work performed by Landlord under this Section 8 shall be paid by
          Tenant to Landlord within ten days after Landlord has delivered to
          Tenant an invoice therefor.

               (c). PERFORMANCE OF WORK. All work described in this Section 8
          shall be performed only by Landlord or by contractors and
          subcontractors approved in writing by Landlord. Tenant shall cause all
          contractors and subcontractors to procure and maintain insurance
          coverage against risks, in such amounts, and with such companies as
          Landlord may reasonably require, and to procure payment and
          performance bonds reasonably satisfactory to Landlord covering the
          cost of the work. All such work shall be performed in accordance with
          all legal requirements and in a good and workmanlike manner so as not
          to damage the Premises, the primary structure or structural qualities
          of the Building, or plumbing, electrical lines, or other utility
          transmission facility. All such work which may affect the HVAC,
          electrical system, or plumbing must be approved by the Building's
          engineer of record.

               (d). MECHANIC'S LIENS. Tenant shall not permit any mechanic's
          liens to be filed against the Premises or the Building for any work
          performed, materials furnished or obligation incurred by or at the
          request of Tenant. If such a lien is filed, then Tenant shall, within
          ten days after Landlord has delivered notice of the filing to Tenant,
          either pay the amount of the lien or diligently contest such lien and
          deliver to Landlord a bond or other security reasonably satisfactory
          to Landlord. If Tenant fails to timely take either such action, then
          Landlord may pay the lien claim without inquiry as to the validity
          thereof, and any amounts so paid, including expenses and interest,
          shall be paid by Tenant to Landlord within ten days after Landlord has
          delivered to Tenant an invoice therefor.

USE            9.   Tenant shall occupy and use the Premises only for the
          Permitted Use and shall comply with all laws, orders, rules, and
          regulations relating to the use, condition, and occupancy of the
          Premises. The Premises shall not be used for any use which is
          disreputable or creates extraordinary fire hazards or results in an
          increased rate of insurance on the Building or its contents or the
          storage of any hazardous materials or substances. If, because of
          Tenant's acts, the rate of insurance on the Building or its contents
          increases, Tenant shall pay to Landlord the amount of such increase on
          demand, and acceptance of such payment shall not constitute a waiver
          of any of Landlord's other rights. Tenant shall conduct its business
          and control its agents, employees, and invitees in such a manner as
          not to create any nuisance or interfere with other tenants or Landlord
          in its management of the Building.

ASSIGNMENT
AND
SUBLETTING     10.  (a)  TRANSFERS; CONSENT. Tenant shall not, without the prior
          written consent of Landlord (which shall not be unreasonably withheld,
          conditioned or delayed), (1) assign, transfer, or encumber this Lease
          or any estate or interest herein, whether directly or by operation of
          law, (2) permit any other entity to become Tenant hereunder by merger,
          consolidation, or other reorganization, (3) if Tenant is an entity
          other than a corporation whose stock is publicly traded, permit the
          transfer of an ownership interest in Tenant so as to result in a
          change in the current control of Tenant, (4) sublet any portion of the
          Premises, (5) grant any license, concession, or other right of
          occupancy of any portion of the Premises, or (6) permit the use of the
          Premises by any parties other than Tenant (any of the events listed in
          Sections 10.(a)(1) through 10.(a)(6) being a "TRANSFER"). If Tenant
          requests Landlord's consent to a Transfer, then Tenant shall provide
          Landlord with a written description of all terms and conditions of the
          proposed Transfer, copies of the proposed documentation, and the
          following information about the proposed transferee: name and address;
          reasonably satisfactory information about its business and business
          history; its proposed use of the Premises; banking, financial, and
          other credit information; and general references sufficient to enable
          landlord to determine the proposed transferee's creditworthiness and
          character. Tenant shall reimburse Landlord for its reasonable
          attorneys' fees and other expenses incurred in connection with
          considering any request for its consent to a Transfer. If Landlord
          consents to a proposed Transfer, then the proposed transferee shall
          deliver to Landlord a written agreement whereby it expressly assumes
          the Tenant's obligations hereunder; however, any transferee of less
          than all of the space in the Premises shall be liable only for
          obligations under this Lease that are properly allocable to the space
          subject to the Transfer, and only to the extent of the rent it has
          agreed to pay Tenant therefor. Landlord's consent to a Transfer shall
          not release Tenant from performing its obligations under this Lease,
          but rather Tenant and its transferee shall be jointly and severally
          liable therefor. Landlord's consent to any Transfer shall not waive
          Landlord's rights as to any subsequent Transfers. If an Event of
          Default occurs while the Premises or any part thereof are subject to a
          Transfer, then Landlord, in addition to its other remedies, may
          collect directly from such transferee all rents becoming due to Tenant
          and apply such rents against Rent. Tenant authorizes its transferees
          to make payments of rent directly to Landlord upon receipt of notice
          from Landlord to do so provided such notice states that an Event of
          Default has occurred and is continuing. Notwithstanding the foregoing,
          Tenant may assign the Lease or sublease all or any portion of the
          Premises without Landlord's consent to any of the following (a
          "Permitted Transferee"), provided that the Permitted Transferee's
          financial condition, creditworthiness and business reputation
          following the transfer are equal to or exceed those of Tenant: (i) any
          successor corporation or other entity resulting from a merger or
          consolidation of Tenant; (ii) any purchaser of all or substantially
          all of Tenant's assets; or (iii) any entity which controls, is
          controlled by, or is under common control with Tenant; provided
          further, however, that a Permitted Transferee shall also include a
          sublessee that is an entity in which Tenant owns or controls greater
          than fifty percent (50%) of the ownership interests [or the right to
          vote such

                                       5
<PAGE>

          ownership interest] and is in the same or similar business as Tenant
          without regard to such sublessee's financial condition or
          creditworthiness. Tenant shall give Landlord thirty (30) days prior
          written notice of such assignment or sublease. Any Permitted
          Transferee (other than a sublessee) shall assume in writing all of
          Tenant's obligations under this Lease. Tenant shall nevertheless at
          all times remain fully responsible and liable for the payment of rent
          and the performance and observance of all of Tenant's other
          obligations under this Lease. Nothing in this paragraph is intended to
          nor shall permit Tenant to transfer its interest under this Lease as
          part of a fraud or subterfuge to intentionally avoid its obligations
          under this Lease (for example, transferring its interest to a shell
          corporation that subsequently files a bankruptcy), and any such
          transfer shall constitute a Default hereunder.

               (b)  CANCELLATION. Landlord may, within ten (10) days after
          submission of Tenant's written request for Landlord's consent to a
          Transfer (except to a Permitted Transfer), cancel this Lease (or, as
          to a subletting or assignment, cancel as to the portion of the
          Premises proposed to be sublet or assigned) as of the date the
          proposed Transfer was to be effective. Notwithstanding the foregoing,
          Landlord shall not have a cancellation right with respect to a
          sublease that covers less than fifty percent (50%) of the Premises
          and is for less than three (3) years. If Landlord cancels this Lease
          as to any portion of the Premises, then this Lease shall cease for
          such portion of the Premises and Tenant shall pay to Landlord all
          Rent accrued through the cancellation date relating to the portion
          of the Premises covered by the proposed Transfer. Thereafter,
          Landlord may lease such portion of the Premises to the prospective
          transferee (or to any other person) without liability to Tenant.

               (c) ADDITIONAL COMPENSATION. Tenant shall pay to Landlord,
          immediately upon receipt thereof, one-half (1/2) of all compensation
          received by Tenant for a Transfer that exceeds the sum of the Basic
          Rental and Tenant's share of Basic Costs allocable to the portion of
          the Premises covered thereby; provided, however, that Tenant shall be
          allowed to recoup its reasonable out of pocket expenses incurred in
          such Transfer (attorney's fees, brokerage commissions and costs of
          retrofitting the Premises) from such excess compensation before paying
          one-half (1/2) of such excess compensation to Landlord.
          Notwithstanding the foregoing, Tenant shall not be required to pay to
          Landlord additional compensation received by Tenant for a Transfer if
          (i) such Transfer is to a Permitted Transferee or (ii) such additional
          compensation is in the form of non-monetary compensation such as
          assignment of intellectual properties or warrants for shares of stock.

INSURANCE;
WAIVERS;
SUBROGATION;
INDEMNITY      11.  (a)  TENANT'S INSURANCE. Tenant shall at its expense procure
          and maintain throughout the Term the following insurance policies: (1)
          comprehensive general liability insurance in amounts of not less than
          a combined single limit of $3,000,000 (the "INITIAL LIABILITY
          INSURANCE AMOUNT") or such other amounts as Landlord may from time to
          time reasonably require, insuring Tenant, Landlord, Landlord's agents
          and their respective affiliates against all liability for injury to or
          death of a person or persons or damage to property arising from the
          use and occupancy of the Premises by Tenant, (2) contractual liability
          insurance coverage sufficient to cover Tenant's indemnity obligations
          hereunder, (3) insurance covering the full value of Tenant's property
          and improvements, and other property (including property of others),
          in the Premises, (4) workman's compensation insurance, containing a
          waiver of subrogation endorsement reasonably acceptable to Landlord,
          and (5) business interruption insurance. Tenant's insurance shall
          provide primary coverage to Landlord when any policy issued to
          Landlord provides duplicate or similar coverage, and in such
          circumstance Landlord's policy will be excess over Tenant's policy.
          Tenant shall furnish certificates of such insurance and such other
          evidence satisfactory to Landlord of the maintenance of all insurance
          coverages required hereunder, and Tenant shall obtain a written
          obligation on the part of each insurance company to notify Landlord at
          least 30 days before cancellation or a material change of any such
          insurance. All such insurance policies shall be in form, and issued by
          companies, reasonably satisfactory to Landlord, The term "AFFILIATE "
          shall mean any person or entity which, directly or indirectly,
          controls, is controlled by, or is under common control with the party
          in question.

               (b)  LANDLORD'S INSURANCE. Landlord shall, during the term,
          maintain in full force the following insurance: (i) commercial general
          liability insurance insuring against any liability due to injury or
          death to any person or loss of or damage to property arising out of
          the operations of Landlord at the Building and/or arising out of the
          common areas, with coverage limits at least three million dollars
          ($3,000,000.00) per occurrence (which coverage may be through blanket
          or umbrella policies), and (ii) All-Risk Property insurance, issued by
          one or more insurance carriers covering the Building to the extent of
          its full replacement value (exclusive of improvements above building
          standard and foundation and excavation costs and other uninsurable
          parts).

               (c)  WAIVER OF NEGLIGENCE CLAIMS; NO SUBROGATION. Landlord shall
          not be liable to Tenant or those claiming by, through, or under Tenant
          for any injury to or death of any person or persons or the damage to
          or theft, destruction, loss, or loss of use of any property or
          inconvenience (a "LOSS") caused by casualty, theft, fire, third
          parties, or any other matter (including Losses arising through repair
          or alteration of any part of the Building, or failure to make repairs,
          or from any other cause), REGARDLESS OF WHETHER THE NEGLIGENCE OF ANY
          PARTY CAUSED SUCH LOSS IN WHOLE OR IN PART EXCEPT FOR GROSS NEGLIGENCE
          OR WILLFUL MISCONDUCT OF LANDLORD OR ITS AGENTS. Landlord and Tenant
          each waives any claim it might have against the other for any

                                       6
<PAGE>

          damage to or theft, destruction, loss, or loss of use of any property,
          to the extent the same is insured against under any insurance policy
          that covers the Building, the Premises, Landlord's or Tenant's
          fixtures, personal property, leasehold improvements, or business, or,
          in the case of Tenant's waiver, is required to be insured against
          under the terms hereof, REGARDLESS OF WHETHER THE NEGLIGENCE OR FAULT
          OF THE OTHER PARTY CAUSED SUCH LOSS; HOWEVER, LANDLORD'S WAIVER SHALL
          NOT INCLUDE ANY DEDUCTIBLE AMOUNTS ON INSURANCE POLICIES CARRIED BY
          LANDLORD OR APPLY TO ANY COINSURANCE PENALTY WHICH LANDLORD MIGHT
          SUSTAIN. Each party shall cause its insurance carrier to endorse all
          applicable policies waiving the carrier's rights of recovery under
          subrogation or otherwise against the other party.

               (d)  INDEMNITY. Subject to Section 11.(b), Tenant shall defend,
          indemnify, and hold harmless Landlord and its agents from and against
          all claims, demands, liabilities, causes of action, suits, judgments,
          and expenses (including reasonable attorneys' fees) for any Loss
          arising from any occurrence on the Premises or from Tenant's failure
          to perform its obligations under this Lease (other than a Loss arising
          from the sole or gross negligence or willful acts of Landlord or its
          agents), even though caused or alleged to be caused by the joint,
          comparative, or concurrent negligence or fault of Landlord or its
          agents. THIS INDEMNITY PROVISION IS INTENDED TO INDEMNIFY LANDLORD AND
          ITS AGENTS AGAINST THE CONSEQUENCES OF THEIR OWN NEGLIGENCE OR FAULT
          AS PROVIDED ABOVE WHEN LANDLORD OR ITS AGENTS ARE JOINTLY,
          COMPARATIVELY, OR CONCURRENTLY NEGLIGENT WITH TENANT. This indemnity
          provision shall survive termination or expiration of this Lease.

SUBORDINATION
ATTORNMENT;
NOTICE TO
LANDLORD'S
MORTGAGEE

               12.  (a)  SUBORDINATION. This Lease is subordinate to any deed
          of trust, mortgage, or other security instrument (a "MORTGAGE"),
          or any ground lease, master lease, or primary lease (a "PRIMARY
          LEASE"), that now or hereafter covers all or any part of the
          Premises (the mortgagee under any Mortgage or the lessor under any
          Primary Lease is referred to herein as "LANDLORD'S MORTGAGEE"). The
          provisions of this Section 12(a) shall be self-operative, and no
          further instrument shall be required to effect such subordination;
          however, Landlord shall deliver to Tenant, and Tenant shall execute
          from time to time within ten days after delivery to Tenant, an
          instrument from each Landlord's Mortgagee evidencing the
          subordination of this Lease to any such Mortgage or Primary Lease
          (which instrument shall include a non-disturbance provision in
          favor of Tenant and shall be on Landlord's Mortgagee's standard
          form). Notwithstanding the foregoing, Landlord, Tenant and
          Landlord's Mortgagee shall execute and deliver a Subordination,
          Non-disturbance and Attornment Agreement in the form attached as
          Exhibit "H" hereto within ten (10) days after the date hereof.

               (b)  ATTORNMENT. Tenant shall attorn to any party succeeding to
          Landlord's interest in the Premises, whether by purchase, foreclosure,
          deed in lieu of foreclosure, power of sale, termination of lease, or
          otherwise, upon such party's request, and shall execute such
          agreements confirming such attornment as such party may reasonably
          request.

               (c)  NOTICE TO LANDLORD'S MORTGAGEE. Tenant shall not seek to
          enforce any remedy it may have for any default on the part of the
          Landlord without first giving written notice by certified mail, return
          receipt requested, specifying the default in reasonable detail, to any
          Landlord's Mortgagee whose address has been given to Tenant, and
          affording such Landlord's Mortgagee the same opportunity as given to
          Landlord to perform Landlord's obligations hereunder, except as
          otherwise may be provided in any applicable subordination,
          non-disturbance and attornment agreement executed by Landlord, Tenant
          and Landlord's Mortgagee.

RULES
AND
REGULATIONS

               13.  Tenant shall comply with the rules and regulations of the
          Building which are attached hereto as EXHIBIT B. Landlord may, from
          time to time, change such rules and regulations for the safety, care,
          or cleanliness of the Building and related facilities, provided that
          such changes are reasonable, applicable to all tenants of the Building
          evenly enforced and will not unreasonably interfere with Tenant's use
          of the Premises. Tenant shall be responsible for the compliance with
          such rules and regulations by its employees, agents, and invitees.

CONDEMNATION

               14.  (a)  TAKING - LANDLORD'S AND TENANT'S RIGHTS. If any part of
          the Building is taken by right of eminent domain or conveyed in lieu
          thereof (a "TAKING"), and such Taking prevents Tenant from conducting
          its business in the Premises in a manner reasonably comparable to that
          conducted immediately before such Taking, then Landlord may, at its
          expense, relocate Tenant to office space reasonably comparable to the
          Premises within five miles of Premises, provided that Landlord
          notifies Tenant of its intention to do so prior to the effective date
          of the Taking. Such relocation may be for a portion of the remaining
          Term or the entire Term. Landlord shall complete any such relocation
          within 180 days after Landlord has notified Tenant of its intention to
          relocate Tenant. If Landlord does not elect to relocate Tenant
          following such Taking, then Tenant may terminate this Lease as of the
          date of such Taking by giving written notice to Landlord within

                                       7
<PAGE>

          60 days after the Taking, and Rent shall be apportioned as of the date
          of such Taking. If Landlord does not relocate Tenant and Tenant does
          not terminate this Lease, then Rent shall be adjusted on a reasonable
          basis as to that portion of the Premises rendered untenantable by the
          Taking. Correspondingly, the Letter of Credit obligation will be
          adjusted on a reasonable basis in the event of partial Taking or
          eliminated entirely in the event of Lease termination.

               (b)  TAKING - LANDLORD'S RIGHTS. If any material portion, but
          less than all, of the Building becomes subject to a Taking, or if
          Landlord is required to pay any of the proceeds received for a Taking
          to Landlord's Mortgagee, then this Lease, at the option of Landlord,
          exercised by written notice to Tenant within 30 days after such
          Taking, shall terminate and Rent shall be apportioned as of the date
          of such Taking. If Landlord does not so terminate this Lease and does
          not elect to relocate Tenant, then, subject to Tenant's rights under
          14(a), this Lease will continue, but if any portion of the Premises
          has been taken, Basic Rental shall adjust as provided in the last
          sentence of Section 14.(a).

               (c) AWARD. If any Taking occurs, then Landlord shall receive the
          entire award or other compensation for the Land, the Building, and
          other improvements taken, and Tenant may separately pursue a claim
          against the condemner for the value of Tenant's personal property
          which Tenant is entitled to remove under this Lease, moving costs,
          loss of business, and other claims it may have.

FIRE OR
OTHER
CASUALTY       15.  (a)  REPAIR ESTIMATE. If the Premises or the Building are
          damaged by fire or other casualty (a "CASUALTY"), Landlord shall,
          within 60 days after such Casualty, deliver to Tenant a good faith
          estimate (the "DAMAGE NOTICE") of the time needed to repair the damage
          caused by such Casualty.

               (b)  LANDLORD'S AND TENANT'S RIGHTS. If a material portion of the
          Premises or the Building is damaged by Casualty such that Tenant is
          prevented from conducting its business in the Premises in a manner
          reasonably comparable to that conducted immediately before such
          Casualty and Landlord estimates in good faith that the damage caused
          thereby cannot be repaired within 270 days after the date of casualty,
          then Tenant may terminate this Lease by delivering written notice to
          Landlord of its election to terminate within 30 days after the Damage
          Notice has been delivered to Tenant. If Tenant does not terminate this
          Lease, then (subject to Landlord's rights under Section 15.(c))
          Landlord shall repair the Building or the Premises, as the case may
          be, as provided below, and Rent for the portion of the Premises
          rendered untenantable by the damage shall be adjusted on a reasonable
          basis from the date of damage until the completion of the repair.

               (c)  LANDLORD'S RIGHTS. If a Casualty damages a material portion
          of the Building, and Landlord makes a good faith determination that
          restoring the Premises would be uneconomical, or if Landlord is
          required to pay any insurance proceeds arising out of the Casualty to
          Landlord's Mortgagee (such that Landlord would be required to pay
          $100,000.00 or more of its own funds to restore the Building), then
          Landlord may, terminate this Lease by giving written notice of its
          election to terminate within 30 days after the Damage Notice has been
          delivered to Tenant, and Basic Rental hereunder shall be abated as of
          the date of the Casualty.

               (d)  REPAIR OBLIGATION. If neither party elects to
          terminate this Lease following a Casualty, then Landlord shall, within
          a reasonable time after such Casualty, commence to repair the Building
          and the Premises and shall proceed with reasonable diligence to
          restore the Building and Premises to substantially the same condition
          as they existed immediately before such Casualty; however, Landlord
          shall not be required to repair or replace any part of the furniture,
          equipment, fixtures, and other improvements which may have been placed
          by, or at the request of, Tenant or other occupants in the Building or
          the Premises, except for initial improvements pursuant to Exhibit D,
          and Landlord's obligation to repair or restore the Building or
          Premises shall be limited to the extent of the insurance proceeds
          actually received by Landlord for the Casualty in question. If
          Landlord fails to substantially complete the rebuilding and repair of
          the Premises within one (1) year after the date of the casualty, then
          this Lease shall terminate thirty (30) days after Landlord receives
          written notice, if any, from Tenant that Tenant has elected to
          terminate this Lease pursuant to this paragraph; provided that, if
          Landlord substantially completes such rebuilding and repairs prior to
          the expiration of thirty (30) days following Landlord's receipt of
          Tenant's termination notice, this Lease shall not so terminate and
          shall continue in full force and effect.

TAXES          16.  Tenant shall be liable for all taxes levied or assessed
          against personal property, furniture, or fixtures placed by Tenant in
          the Premises. If any taxes for which Tenant is liable are levied or
          assessed against Landlord or Landlord's property and Landlord elects
          to pay the same, or if the assessed value of Landlord's property is
          increased by inclusion of such personal property, furniture or
          fixtures and Landlord elects to pay the taxes based on such increase,
          then Tenant shall pay to Landlord, upon demand, that part of such
          taxes for which Tenant is primarily liable hereunder.

EVENTS OF
DEFAULT        17.  Each of the following occurrences shall constitute an "EVENT
          OF DEFAULT":

                                       8
<PAGE>

               (a)  Tenant's failure to pay Rent, or any other sums due from
          Tenant to Landlord under the Lease when due and such failure continues
          for ten (10) days following written notice from Landlord notifying
          Tenant of Tenant's failure to pay when due; provided, however, that in
          the event Landlord gives to Tenant notice of Tenant's failure to pay
          when due two (2) times in any calendar year, Tenant's failure to pay
          when due the third (3rd) time in such calendar year shall constitute
          an Event of Default immediately without any notice thereof required
          from Landlord;

               (b)  Tenant's failure to perform, comply with, or observe any
          agreement or obligation of Tenant under this Lease (other than a
          payment obligation) on or before the thirtieth (30th) day following
          written notice of such failure or longer time if not curable within
          thirty (30) days provided Tenant is in diligent pursuit to cure such
          failure and in any event such cure is commenced within thirty (30),
          and completed within ninety (90) days, after written notice;

               (c)  the filing of a petition by or against Tenant in any
          bankruptcy or other insolvency proceeding; (2) seeking any relief
          under any state or federal debtor relief law; (3) for the appointment
          of a liquidator or receiver for all or substantially all of Tenant's
          property or for Tenant's interest in this Lease; or (4) for the
          reorganization or modification of Tenant's capital structure; provided
          that Tenant shall have sixty (60) days following the commencement of
          an involuntary proceeding to have such proceeding dismissed before
          such proceeding shall constitute an Event of Default; and

               (d)  the admission by Tenant that it cannot meet its obligations
          as they become due or the making by Tenant of an assignment for the
          benefit of its creditors.

REMEDIES       18.  Upon any Event of Default, Landlord may, in addition to all
          other rights and remedies afforded Landlord hereunder or by law or
          equity, take any of the following actions:

               (a)  Terminate this Lease by giving Tenant written notice
          thereof, in which event, Tenant shall pay to Landlord the sum of (1)
          all Rent accrued hereunder through the date of termination, (2) all
          amounts due under Section 19.(a), and (3) an amount equal to (A) the
          total Rent that Tenant would have been required to pay for the
          remainder of the Term discounted to present value at a per annum rate
          equal to the "Prime Rate" as published on the date this Lease is
          terminated by The Wall Street Journal, Southwest Edition, in its
          listing of "Money Rates", minus (B) the then present fair rental value
          of the Premises for such period, similarly discounted; or

               (b)  Terminate Tenant's right to possession of the Premises
          without terminating this Lease by giving written notice thereof to
          Tenant, in which event Tenant shall pay to Landlord (1) all Rent and
          other amounts accrued hereunder to the date of termination of
          possession, (2) all amounts due from time to time under Section
          19.(a), and (3) all Rent and other sums required hereunder to be paid
          by Tenant during the remainder of the Term, diminished by any net sums
          thereafter received by Landlord through reletting the Premises during
          such period. Landlord shall use reasonable efforts to relet the
          Premises on such terms and conditions as Landlord in its sole
          discretion may determine (including a term different from the Term,
          rental concessions, and alterations to, and improvement of, the
          Premises); however, Landlord shall not be obligated to relet the
          Premises before leasing other portions of the Building. Landlord shall
          not be liable for, nor shall Tenant's obligations hereunder be
          diminished because of, Landlord's failure to relet the Premises or to
          collect rent due for such reletting provided Landlord shall use
          reasonable efforts as set forth herein. Tenant shall not be entitled
          to the excess of any consideration obtained by reletting over the Rent
          due hereunder. Reentry by Landlord in the Premises shall not affect
          Tenant's obligations hereunder for the unexpired Term; rather,
          Landlord may, from time to time, bring action against Tenant to
          collect amounts due by Tenant, without the necessity of Landlord's
          waiting until the expiration of the Term. Unless Landlord delivers
          written notice to Tenant expressly stating that it has elected to
          terminate this Lease, all actions taken by Landlord to exclude or
          dispossess Tenant of the Premises shall be deemed to be taken under
          this Section 18.(b). If Landlord elects to proceed under this Section
          18.(b), it may at any time elect to terminate this Lease under Section
          18.(a).

               Additionally, without notice, Landlord may alter locks or other
          security devices at the Premises to deprive Tenant of access thereto,
          and Landlord shall not be required to provide a new key or right of
          access to Tenant. Notwithstanding the foregoing, Tenant will be
          granted access to the premises for the sole purpose of removal of all
          materials, including documentation, electronic media, computers,
          computers containing electronic media, diagrams, pictures or any other
          property that is confidential or proprietary information of the Tenant
          or of third parties with such access granted to Tenant prior to
          Landlord re-entering the premises; provided that a representative of
          Landlord may be present to insure that Tenant does not remove any
          unauthorized materials. Either party may request such removal within
          three (3) business days or earlier based on compelling business
          reasons by either party for more immediate access.

PAYMENT BY
TENANT;
NON-WAIVER     19.  (a)  PAYMENT BY TENANT. Upon any Event of Default, Tenant
          shall pay to Landlord all costs incurred by Landlord (including court
          costs and reasonable attorneys' fees and expenses) in (1) obtaining
          possession of the Premises, (2) removing and storing Tenant's or any
          other occupant's property, (3) repairing, restoring, altering,
          remodeling, or otherwise putting the Premises into condition
          acceptable to a new tenant, (4) if

                                       9
<PAGE>

          Tenant is dispossessed of the Premises and this Lease is not
          terminated, reletting all or any part of the Premises (including
          brokerage commissions, cost of tenant finish work, and other costs
          incidental to such reletting), (5) performing Tenant's obligations
          which Tenant failed to perform, and (6) enforcing, or advising
          Landlord of, its rights, remedies, and recourses arising out of the
          Event of Default.

               (b)  NO WAIVER. Landlord's acceptance of Rent following an
          Event of Default shall not waive Landlord's rights regarding such
          Event of Default. No waiver by Landlord of any violation or breach
          of any of the terms contained herein shall waive Landlord's rights
          regarding any future violation of such term or violation of any
          other term.

SURRENDER  OF
PREMISES       20.  No act by Landlord shall be deemed an acceptance of a
          surrender of the Premises, and no agreement to accept a surrender
          of the Premises shall be valid unless the same is made in writing
          and signed by Landlord. At the expiration or termination of this
          Lease, Tenant shall deliver to Landlord the Premises with all
          improvements located thereon in good repair and condition,
          reasonable wear and tear (and condemnation and fire or other
          casualty damage, as to which Sections 14 and 15 shall control)
          excepted, and shall deliver to Landlord all keys to the Premises.
          Provided that Tenant has performed all of its obligations
          hereunder, Tenant may remove all unattached trade fixtures,
          furniture, and personal property placed in the Premises by Tenant
          (but Tenant shall not remove any such item which was paid for, in
          whole or in part, by Landlord). Additionally, Tenant shall remove
          such alterations, additions, improvements, trade fixtures,
          equipment, wiring, and furniture that is installed or placed in the
          Premises by Tenant as Landlord may request, except for initial
          improvements pursuant to Exhibit D. Tenant shall repair all damage
          caused by such removal. All items not so removed shall be deemed to
          have been abandoned by Tenant and may be appropriated, sold,
          stored, destroyed, or otherwise disposed of by Landlord without
          notice to Tenant and without any obligation to account for such
          items. The provisions of this Section 20 shall survive the end of
          the Term.

HOLDING
OVER           21.  If Tenant fails to vacate the Premises at the end of the
          Term, then Tenant shall be a tenant at will and, in addition to all
          other damages and remedies to which Landlord may be entitled for
          such holding over, Tenant shall pay, in addition to the other Rent,
          a daily Basic Rental equal to the greater of (a) 150% of the daily
          Basic Rental payable during the last month of the Term, or (b) the
          prevailing rental rate in the Building for similar space.

CERTAIN RIGHTS
RESERVED BY
LANDLORD       22.  Provided that the exercise of such rights does not
          unreasonably interfere with Tenant's occupancy of the Premises,
          Landlord shall have the following rights:

               (a)  to decorate and to make inspections, repairs,
          alterations, additions, changes, or improvements, whether
          structural or otherwise, in and about the Building, or any part
          thereof; for such purposes, to enter upon the Premises and, during
          the continuance of any such work, to temporarily close doors,
          entryways, public space, and corridors in the Building; to
          interrupt or temporarily suspend Building services and facilities;
          and to change the arrangement and location of entrances or
          passageways, doors, and doorways, corridors, elevators, stairs,
          restrooms, or other public parts of the Building;

               (b) to take such reasonable measures as Landlord deems
          advisable for the security of the Building and its occupants,
          including without limitation searching all persons entering or
          leaving the Building; evacuating the Building for cause, suspected
          cause, or for drill purposes; temporarily denying access to the
          Building; and closing the Building after normal business hours and
          on Saturdays, Sundays, and holidays, subject, however, to Tenant's
          right to enter when the Building is closed after normal business
          hours under such reasonable regulations as Landlord may prescribe
          from time to time which may include by way of example, but not of
          limitation, that persons entering or leaving the Building, whether
          or not during normal business hours, identify themselves to a
          security officer by registration or otherwise and that such persons
          establish their right to enter or leave the Building;

               (c)  to change the name by which the Building is designated; and

               (d)  to enter the Premises accompanied by Tenant at all
          reasonable hours and upon giving Tenant reasonable notice (except
          in the case of any emergency) to show the Premises to prospective
          purchasers, lenders, or tenants (provided the space shall only be
          shown to prospective tenants in conjunction with reletting the
          Premises), subject to reasonable Tenant security and
          confidentiality procedures.

MISCELLANEOUS  24.  (a)  LANDLORD TRANSFER. Landlord may transfer, in whole
          or in part, the Building and any of its rights under this Lease. If
          Landlord assigns its rights under this lease, and the assignee
          assumes all Landlord's obligation under this Lease, then Landlord
          shall thereby be released from any further obligations hereunder
          arising after the date of such transfer.

                                      10
<PAGE>

               (b)  LANDLORD'S LIABILITY. The liability of Landlord to Tenant
          for any default by Landlord under the terms of this Lease shall be
          limited to Tenant's actual direct, but not consequential, damages
          therefor and shall be recoverable from the interest of Landlord in
          the Building and the Land, and Landlord shall not be personally
          liable for any deficiency. This section shall not be deemed to
          limit or deny any remedies which Tenant may have in the event of
          default by Landlord hereunder which do not involve the personal
          liability of Landlord.

               (c)  FORCE MAJEURE. Other than for Tenant's monetary
          obligations under this Lease and obligations which can be cured by
          the payment of money (e.g., maintaining insurance), whenever a
          period of time is herein prescribed for action to be taken by
          either party hereto, such party shall not be liable or responsible
          for, and there shall be excluded from the computation for any such
          period of time, any delays due to strikes, riots, acts of God,
          shortages of labor or materials, war, governmental laws,
          regulations (including inability to obtain necessary permits due to
          no fault of Landlord or its contractors or agents), or
          restrictions, or any other causes of any kind whatsoever which are
          beyond the control of such party.

               (d)  BROKERAGE. Landlord and Tenant each warrant to the other
          that it has not dealt with any broker or agent in connection with
          the negotiation or execution of this Lease, except for Insignia/ESG
          of Texas, Inc. (Landlord's exclusive agent) and Colliers Oxford
          Commercial (Tenant's exclusive agent). Tenant and Landlord shall
          each indemnify the other against all costs, expenses, reasonable
          attorneys' fees, and other liability for commissions or other
          compensation claimed by any broker or agent claiming the same by,
          through, or under the indemnifying party.

               (e)  ESTOPPEL CERTIFICATES AND FINANCIAL INFORMATION. From
          time to time, Tenant shall furnish to any party designated by
          Landlord, within ten days after Landlord has made a request
          therefor, a certificate signed by Tenant confirming and containing
          such factual certifications and representations as to this Lease as
          Landlord may reasonably request. From time to time, Landlord shall
          furnish to any party designated by Tenant, within ten days after
          Tenant has made a request therefor, a certificate signed by
          Landlord confirming and containing such factual certifications and
          representations as to this Lease as Tenant may reasonably request.
          Further, from time to time (but not more often than once in any
          given six (6) month period), within ten days after Landlord's
          request therefor, Tenant shall furnish to Landlord or Landlord's
          Mortgagee the most recent annual financial statements for Tenant.

               (f)  NOTICES. All notices and other communications given
          pursuant to this Lease shall be in writing and shall be (1) mailed
          by first class, United States Mail, postage prepaid, certified,
          with return receipt requested, and addressed to the parties hereto
          at the address specified in the Basic Lease Information, (2) hand
          delivered or delivered by overnight delivery service to the
          intended address, or (3) sent by prepaid telegram, cable, facsimile
          transmission, or telex followed by a confirmatory letter. Notice
          sent by certified mail, postage prepaid, shall be effective three
          business days after being deposited in the United States Mail; all
          other notices shall be effective upon delivery to the address of
          the addressee. The parties hereto may change their addresses by
          giving notice thereof to the other in conformity with this
          provision.

               (g)  SEPARABILITY. If any clause or provision of this Lease is
          illegal, invalid, or unenforceable under present or future laws,
          then the remainder of this Lease shall not be affected thereby and
          in lieu of such clause or provision, there shall be added as a part
          of this Lease a clause or provision as similar in terms to such
          illegal, invalid, or unenforceable clause or provision as may be
          possible and be legal, valid, and enforceable.

               (h)  AMENDMENTS; AND BINDING EFFECT. This Lease may not be
          amended except by instrument in writing signed by Landlord and
          Tenant. No provision of this Lease shall be deemed to have been
          waived by Landlord unless such waiver is in writing signed by
          Landlord, and no custom or practice which may evolve between the
          parties in the administration of the terms hereof shall waive or
          diminish the right of Landlord to insist upon the performance by
          Tenant in strict accordance with the terms hereof. The terms and
          conditions contained in this Lease shall inure to the benefit of
          and be binding upon the parties hereto, and upon their respective
          successors in interest and legal representatives, except as
          otherwise herein expressly provided. This Lease is for the sole
          benefit of Landlord and Tenant, and, other than Landlord's
          Mortgagee, no third party shall be deemed a third party beneficiary
          hereof.

               (i)  QUIET ENJOYMENT. Provided Tenant has performed all of the
          terms and conditions of this Lease to be performed by Tenant,
          Tenant shall peaceably and quietly hold and enjoy the Premises for
          the Term, without hindrance from Landlord or any party claiming by,
          through, or under Landlord, subject to the terms and conditions of
          this Lease.

               (j)  JOINT AND SEVERAL LIABILITY. If there is more than one
          Tenant, then the obligations hereunder imposed upon Tenant shall be
          joint and several.

               (k)  CAPTIONS. The captions contained in this Lease are for
          convenience of reference only, and do not limit or enlarge the
          terms and conditions of this Lease.

               (l)  NO MERGER. There shall be no merger of the leasehold
          estate hereby created with the fee

                                      11
<PAGE>

          estate in the Premises or any part thereof if the same person
          acquires or holds, directly or indirectly, this Lease or any
          interest in this Lease and the fee estate in the leasehold Premises
          or any interest in such estate.

               (m)  NO OFFER. The submission of this Lease to Tenant shall
          not be construed as an offer, nor shall Tenant have any right under
          this Lease unless Landlord executes a copy of this Lease and
          delivers it to Tenant.

               (n)  EXHIBITS. All exhibits and attachments hereto are
          incorporated herein by this reference.

                       Exhibit A      -  Land
                       Exhibit A-1   -  Outline of Premises
                       Exhibit A-2    -  Project
                       Exhibit B      -  Building Rules and Regulation
                       Exhibit C      -  Basic Costs
                       Exhibit D      -  Tenant Finish-Work
                       Exhibit E      -  Parking
                       Exhibit F      -  Extension Option
                       Exhibit G      -  Right of First Refusal
                       Exhibit H      -  Subordination, Non-disturbance and
                                         Attornment Agreement
                       Exhibit I      -  Pro Forma Letter of Credit
                       Exhibit J      -  Confidentiality Agreement

               (o)  ENTIRE AGREEMENT. This Lease constitutes the entire
          agreement between Landlord and Tenant regarding the subject matter
          hereof and supersedes all oral statements and prior writings
          relating thereto. Except for those set forth in this Lease, no
          representations, warranties, or agreements have been made by
          Landlord or Tenant to the other with respect to this Lease or the
          obligations of Landlord or Tenant in connection therewith.

HAZARDOUS
SUBSTANCES     25.  The term "HAZARDOUS SUBSTANCES," as used in this Lease
          shall mean pollutants, contaminants, toxic or hazardous wastes, or
          any other substances, the removal of which is required or the use
          of which is restricted, prohibited or penalized by any
          "ENVIRONMENTAL LAW," which term shall mean any Law relating to
          health, pollution, or protection of the environment. Tenant hereby
          agrees that a). no activity will be conducted on the Premises that
          will produce any Hazardous Substances, except for such activities
          that are part of the ordinary course of Tenant's business
          activities (the "PERMITTED ACTIVITIES") provided such Permitted
          Activities are conducted in accordance with all Environmental Laws
          and have been approved in advance in writing by Landlord; b). the
          Premises will not be used in any manner for the storage of any
          Hazardous Substances except for any temporary storage of such
          materials that are used in the ordinary course of Tenant's business
          (the "PERMITTED MATERIALS") provided such Permitted Materials are
          properly stored in a manner and location satisfying all
          Environmental Laws and approved in advance in writing by Landlord;
          c). no portion of the Premises will be used as a landfill or a
          dump; d). Tenant will not install any underground tanks of any
          type; e). Tenant will not cause any surface or subsurface
          conditions to exist or come into existence that constitute, or with
          the passage of time may constitute a public or private nuisance;
          f). Tenant will not permit any Hazardous Substances to be brought
          onto the Premises, except for the Permitted Materials, and if so
          brought or found located thereon, the same shall be immediately
          removed by Tenant, with proper disposal, and all required cleanup
          procedures shall be diligently undertaken pursuant to all
          Environmental Laws; g). Tenant will maintain on the Premises a list
          of all materials stored at the Premises for which a material safety
          data sheet (an "MSDS") was issued by the producers or manufacturers
          thereof, together with copies of the MSDS's for such materials, and
          shall deliver such list and MSDS copies to Landlord upon Landlord's
          request therefor; and h). Tenant shall remove all Permitted
          Materials from the Premises in a manner acceptable to Landlord
          before Tenant's right to possess the Premises is terminated. If at
          any time during or after the Term, the Premises are found to be so
          contaminated or subject to such conditions, Tenant shall defend,
          indemnify and hold Landlord harmless from all claims, demands,
          actions, liabilities, costs, expenses, damages and obligations of
          any nature arising from or as a result of the use of the Premises
          by Tenant, except for any conditions or contamination caused by
          Landlord. The foregoing indemnity shall survive termination or
          expiration of this Lease. Unless expressly identified on an
          addendum to this Lease, as of the date hereof there are no
          "Permitted Activities" or "Permitted Materials" for purposes of the
          foregoing provision and none shall exist unless and until approved
          in writing by the Landlord. Landlord may enter the Premises and
          conduct environmental inspections and tests therein as it may
          reasonably require from time to time, provided that Landlord shall
          use reasonable efforts to minimize the interference with Tenant's
          business. Such inspections and tests shall be conducted at
          Landlord's expense, unless they reveal the presence of Hazardous
          Substances brought by Tenant or its employees, representatives or
          agents to the Premises (other than Permitted Materials or those
          placed in the Premises by Landlord) or that Tenant has not complied
          with the requirements set forth in this Section 25, in which case
          Tenant shall reimburse Landlord for the cost thereof within ten
          days after Landlord's request therefor. In no event shall Tenant be
          liable for Hazardous Substances on the Premises prior to the
          Commencement Date, unless brought to the Premises by Tenant or its
          employees, representatives or agents.

                                       12
<PAGE>

LANDLORD'S
LIEN           26. Tenant shall have the right to grant any security
          interests in Tenant's removable furniture, fixtures and equipment
          located in the Premises for the purpose of securing any
          indebtedness provided by a third party. Tenant may also lease such
          furniture, fixtures and / or equipment from one or more equipment
          lessors and grant security interests in such furniture, fixtures
          and/or equipment to such equipment lessors in connection with such
          leases. Upon request Landlord will execute one or more consent
          and/or subordination agreements subordinating any landlord's lien
          rights held by Landlord to any such security interests or leases.
          Notwithstanding the foregoing, in no event will Tenant have the
          right to grant any lien, mortgage or security interest in any
          portion of the Building or in this Lease.

SPECIAL PROVISIONS

               27.  Landlord agrees that Tenant may, at Tenant's expense,
erect and maintain lettering bearing Tenant's name at the top position of the
monument sign associated with the Building, such lettering to represent fifty
percent (50%) of the graphical portion of such monument sign which is
designated for use by tenants (subject to Landlord's reasonable approval of
the size, design, form, content and location of such sign). If any other
tenant in the Building which leases less space than the Premises is permitted
to place signage on the Building, Tenant shall also be permitted to install
and maintain a sign bearing Tenant's name on the exterior of the Building
[such sign to be (i) larger than such other tenant's sign in proportion to the
amount by which the square footage of the Premises exceeds the square footage
of such other tenant's premises and (ii) mutually agreed to by Landlord and
Tenant as to design, form, content and location]. Tenant shall be solely
responsible for all costs of designing, installing and repairing such
signage, diligently construct such building signage to completion in a good
and workmanlike manner and maintain such signage in an attractive condition,
and comply with all governmental codes and regulations. Upon termination or
expiration of this Lease, Tenant shall remove such signage and repair any
damage to the Building caused thereby at its sole cost and expense.
Notwithstanding anything to the contrary contained in this Lease, Tenant
hereby indemnifies and holds Landlord harmless against any claims, costs or
expenses (including reasonable attorneys fees) in connection with any damages
to property or injuries to persons arising out of the installation, removal
or maintenance of such building signage.

          28.  Notwithstanding any thing contained in this Lease to the
contrary, Landlord's obligations hereunder are specifically conditioned upon
Landlord achieving Substantial Completion of the Premises not later than
August 1, 2000, which date shall be extended day-for-day for each day of
Tenant Delay (the "Outside Date"). In the event Landlord does not achieve
Substantial Completion of the Premises by the Outside Date, Tenant, as
Tenant's sole and exclusive remedy, may terminate this Lease in writing at
any time after the Outside Date and before Landlord achieves Substantial
Completion of the Premises. In the event Tenant terminates this Lease
pursuant to this paragraph, Landlord will return all advance payments of rent
and Security Deposits theretofore paid to Landlord by Tenant and all Letters
of Credit theretofore delivered to Landlord by Tenant and will reimburse and
refund Tenant all monies theretofore paid by Tenant to Landlord as part of
Total Construction Costs (in accordance with Exhibit D); provided, however,
in no event shall such reimbursement of amounts paid for Total Construction
Costs exceed an amount equal to the product of $6.00 multiplied by the number
of rentable square feet within the Premises.

          29.  Notwithstanding anything contained in this Lease to the
contrary, if Landlord fails to deliver the nondisturbance agreement to Tenant
contemplated by Section 12(a) hereof executed by Landlord and Landlords'
Mortgagee within thirty (30) days after the date this Lease is signed by
Landlord and Tenant, Tenant shall have the right to terminate this Lease upon
written notice to Landlord at any time prior to delivery of such agreement.

          30.  Contemporaneously herewith, Landlord shall execute and deliver
to Tenant a Confidentiality Agreement in the form of Exhibit "J" attached
hereto.

LANDLORD AND TENANT EXPRESSLY DISCLAIM ANY IMPLIED WARRANTY THAT THE PREMISES
ARE SUITABLE FOR TENANT'S INTENDED COMMERCIAL PURPOSE, AND TENANT'S
OBLIGATION TO PAY RENT HEREUNDER IS NOT DEPENDENT UPON THE CONDITION OF THE
PREMISES OR THE PERFORMANCE BY LANDLORD OF ITS OBLIGATIONS HEREUNDER EXCEPT
AS OTHERWISE EXPRESSLY PROVIDED HEREIN, AND, EXCEPT AS OTHERWISE EXPRESSLY
PROVIDED HEREIN, TENANT SHALL CONTINUE TO PAY THE RENT, WITHOUT ABATEMENT,
SETOFF, DEDUCTION, NOTWITHSTANDING ANY BREACH BY LANDLORD OF ITS DUTIES OR
OBLIGATIONS HEREUNDER, WHETHER EXPRESS OR IMPLIED.

                                      13
<PAGE>

DATED as of the date first written above.

                 LANDLORD:

                 STRATUS 7000 WEST JOINT VENTURE
                 a Texas joint venture

                 By:  OLY LANTANA, L.P., a Texas limited
                      partnership, Joint Venturer

                      By:  OLY LANTANA, GP, L.L.C., a Texas
                           limited liability company, its General Partner

                           By: /s/ Hal R. Hall
                              -------------------------
                           Name:
                                -----------------------
                           Title:
                                 ----------------------

                      By: STRATUS 7000 WEST, LTD., a Texas limited
                          partnership, Joint Venturer

                          By:  STRS, L.L.C., a Delaware limited liability
                               company, General Partner

                               By STRATUS PROPERTIES INC., a Delaware
                                  limited liability company, its sole member

                               By: /s/ William H. Armstrong, III
                                  ---------------------------------------
                                  William H. Armstrong, III
                                  President and CEO

                          TENANT:

                          SILICON LABORATORIES, INC.

                                    By: /s/ Navdeep S. Sooch
                                       ---------------------------------------
                                       Navdeep S. Sooch
                                       Chairman and CEO

                                     14
<PAGE>

                                    EXHIBIT A

                                      LAND

                              PROPERTY DESCRIPTION

Lot 6, Block A, LANTANA LOT 6, BLOCK A, a subdivision in Travis County, Texas,
according to the map or plat thereof, recorded in Volume 100, Page(s) 1-2 of the
Plat Records of Travis County, Texas, as corrected by instrument recorded in
Volume 13064, Page 278 of the Real Property Records of Travis County, Texas.

                                       A-1
<PAGE>

                                  EXHIBIT A-1

                              OUTLINE OF PREMISES

                                  [FLOOR PLAN]

                                    LEVEL 2

                                  [FLOOR PLAN]

                                    LEVEL 1

                                     A-1-1

<PAGE>

                                  EXHIBIT A-1

                                    PROJECT

                                  [FLOOR PLAN]

                                                     LANTANA CORPORATE CENTER
                                                     STRATUS PROPERTIES, INC.

                                     A-2-1

<PAGE>

                                    EXHIBIT B

                         BUILDING RULES AND REGULATIONS

     The following rules and regulations shall apply to the Premises, the
Building, the parking garage associated therewith, the Land and the
appurtenances thereto:

1.   Sidewalks, doorways, vestibules, halls, stairways, and other similar
     areas shall not be obstructed by tenants or used by any tenant for
     purposes other than ingress and egress to and from their respective
     leased premises and for going from one to another part of the Building.

2.   Plumbing, fixtures and appliances shall be used only for the purposes
     for which designed, and no sweepings, rubbish, rags or other unsuitable
     material shall be thrown or deposited therein. Damage resulting to any
     such fixtures or appliances from misuse by a tenant or its agents,
     employees or invitees, shall be paid by such tenant.

3.   No signs, advertisements or notices shall be painted or affixed on or to
     any windows or doors or other part of the Building without the prior
     written consent of Landlord. No nails, hooks or screws shall be driven
     or inserted in any part of the Building except by Building maintenance
     personnel. No curtains or other window treatments shall be placed
     between the glass and the Building standard window treatments.

4.   Landlord shall provide and maintain an alphabetical directory for all
     tenants in the main lobby of the Building.

5.   Landlord shall provide all door locks in each tenant's leased premises,
     at the cost of such tenant, and no tenant shall place any additional
     door locks in its leased premises without Landlord's prior written
     consent. Landlord shall furnish to each tenant a reasonable number of
     keys and card keys to such tenant's leased premises, at such tenant's
     cost, and no tenant shall make a duplicate thereof.

6.   Movement in or out of the Building of furniture or office equipment, or
     dispatch or receipt by tenants of any bulky material, merchandise or
     materials which require use of elevators or stairways, or movement
     through the Building entrances or lobby shall be conducted under
     Landlord's supervision at such times and in such a manner as Landlord
     may reasonably require. Each tenant assumes all risks of and shall be
     liable for all damage to articles moved and injury to persons or public
     engaged or not engaged in such movement, including equipment, property
     and personnel of Landlord if damaged or injured as a result of acts in
     connection with carrying out this service for such tenant.

7.   Landlord may prescribe weight limitations and determine the locations
     for safes and other heavy equipment or items, which shall in all cases
     be placed in the Building so as to distribute weight in a manner
     acceptable to Landlord which may include the use of such supporting
     devices as Landlord may require. All damages to the Building caused by
     the installation or removal of any property of a tenant, or done by a
     tenant's property while in the Building, shall be repaired at the
     expense of such tenant.

8.   Corridor doors, when not in use, shall be kept closed. Nothing shall be
     swept or thrown into the corridors, halls, elevator shafts or stairways.
     No birds or animals shall be brought into or kept in, on or about any
     tenant's leased premises. No portion of any tenant's leased premises
     shall at any time be used or occupied as sleeping or lodging quarters.

9.   Tenant shall cooperate with Landlord's employees in keeping its leased
     premises neat and clean. Tenants shall not employ any person for the
     purpose of such cleaning other than the Building's cleaning and
     maintenance personnel.

10.  Tenant shall not make or permit any improper, objectionable or
     unpleasant noises or odors in the Building or otherwise interfere in any
     way with other tenants or persons having business with them.

11.  No machinery of any kind (other than normal office equipment) shall be
     operated by any tenant on its leased area without Landlord's prior
     written consent, nor shall any tenant use or keep in the Building any
     flammable or explosive fluid or substance.

12.  Landlord will not be responsible for lost or stolen personal property,
     money or jewelry from tenant's leased premises or public or common areas
     regardless of whether such loss occurs when the area is locked against
     entry or not.

13.  All mail chutes located in the Building shall be available for use by
     Landlord and all tenants of the Building according to the rules of the
     United States Postal Service.

                                      B-1
<PAGE>

                                   EXHIBIT C

                                  BASIC COSTS

The term "BASIC COST" shall mean all expenses and disbursements of every kind
(subject to the limitations set forth below) which Landlord incurs, pays or
becomes obligated to pay in connection with the ownership, operation, and
maintenance of the Building (including the associated parking facilities),
determined in accordance with generally accepted federal income tax basis
accounting principles consistently applied, including but not limited to the
following:

1.   Wages and salaries (including reasonable management fees) of all
     employees engaged in the operation, repair, replacement, maintenance,
     and security of the Building, including taxes, insurance and benefits
     relating thereto;

2.   All supplies and materials used in the operation, maintenance, repair,
     replacement, and security of the Building;

3.   Annual cost of all capital improvements made to the Building which
     although capital in nature can reasonably be expected to reduce the
     normal operating costs of the Building, as well as all capital
     improvements made in order to comply with any law hereafter promulgated
     by any governmental authority, as amortized over the useful economic
     life of such improvements as determined by Landlord in its reasonable
     discretion (without regard to the period over which such improvements
     may be depreciated or amortized for federal income tax purposes);

4.   Cost of all utilities, other than the cost of utilities actually
     reimbursed to Landlord by the Building's tenants (including Tenant under
     Section 7.(b) of this Lease);

5.   Cost of any insurance applicable to the Building and Landlord's personal
     property used in connection therewith;

6.   Cost of repairs, replacements, and general maintenance of the Building;
     and

7.   Cost of service or maintenance contracts with independent contractors
     for the operation, maintenance, repair, replacement, or security of the
     Building (including, without limitation, alarm service, window cleaning,
     and elevator maintenance).

The term "Basic Cost" shall also mean the Building's Proportionate Share of
Taxes (described below) and all expenses and disbursements of every kind
(subject to the limitations set forth below) which Landlord incurs, pays or
becomes obligated to pay in connection with the ownership, operation and
maintenance of the common areas of the Project (including the associated
parking facilities, driveways and landscaped areas), determined in accordance
with generally accepted federal income tax basis accounting principles
consistently applied, including but not limited to the following:

     (1)  Annual cost of all capital improvements made to the common areas
          which although capital in nature can reasonably be expected to
          reduce the normal operating costs of the Project, as well as all
          capital improvements made in order to comply with any law hereafter
          promulgated by any governmental authority, as amortized over the
          useful economic life of such improvements as determined by Landlord
          in its reasonable discretion (without regard to the period over
          which such improvements may be depreciated or amortized for federal
          income tax purposes);

     (2)  Cost of all utilities for the common areas of the Project
          (including, without limitation, landscape irrigation and parking
          lot lighting), other than the costs of utilities actually
          reimbursed to Landlord by the tenants of the Project;

     (3)  Cost of any insurance applicable to the common areas of the Project
          and Landlord's personal property used in connection therewith;

     (4)  Cost of repairs, replacements and general maintenance of the common
          areas of the Project; and

     (5)  Cost of service or maintenance contracts with independent
          contractors for the operation, maintenance, repair and replacement
          of the common area improvements.

As used herein the term "TAXES" shall mean all taxes and assessments and
governmental charges whether federal, state, county or municipal and whether
they be by taxing or management districts or authorities presently taxing or
by others, subsequently created or otherwise, and any other taxes and
assessments attributable to the Project (or its operation), including the
buildings and the grounds, parking areas, driveways and alleys around the
buildings, excluding, however, federal and state taxes on income and Texas
State Franchise Tax. If the present method of taxation changes so that in
lieu of the whole or any part of any Taxes levied on the Project, there is
levied on Landlord a capital tax directly on the rents received therefrom or
a franchise tax, assessment, or charge based, in whole or in part, upon such
rents, then all such taxes, assessments, or charges, or the part thereof so
based, shall

                                     C-1
<PAGE>

be deemed to be included within the term "Taxes" for the purposes hereof.

     There are specifically excluded from the definition of the term "Basic
Cost" (a) costs for capital improvements made to the Building, other than
capital improvements described in subparagraphs 3 and (1) above of this
Exhibit and except for items which, though capital for accounting purposes,
are properly considered maintenance and repair items, such as painting of
common areas, replacement of carpet in elevator lobbies, and the like; for
repair, replacements and general maintenance paid by proceeds of insurance or
by Tenant or other third parties, and alterations attributable solely to
tenants of the Building other than Tenant; for interest, amortization or
other payments on loans to Landlord; for depreciation of the Building; for
leasing commissions; for legal expenses, other than those incurred for the
general benefit of the Building's tenants (e.g., tax disputes); for
renovating or otherwise improving space for occupants of the Building or
vacant space in the Building; for overtime or other expenses of Landlord in
curing defaults or performing work expressly provided in this Lease to be
borne at Landlord's expense; for federal income taxes imposed on or measured
by the income of Landlord from the operation of the Building for state income
taxes, net profits taxes, Texas Franchise taxes, estate and inheritance
taxes, any utilities charged directly to and paid by Tenant or any other
tenant of the Building or the Project; any amortization costs or rental
expenses incurred with respect to machinery, equipment or improvements
installed for the exclusive benefit of another tenant in the Project;
improvements installed for the exclusive benefit of another tenant of the
Project; management fees that exceed customary and standard management fees
paid in arms length transactions and leasing and brokerage commissions and
legal fees incurred in connection with Landlord's leasing of the Building or
the Project or involving disputes with other tenants of the Project; personal
property taxes owed by other tenants of any building of the Project;
penalties and interest for late payment of taxes due by Landlord and timely
paid by Tenant, or due to violation of laws or governmental regulations;
costs of work or services furnished or performed on behalf of other tenants
at such tenant's costs; fees payable to affiliates of Landlord outside the
range of fees payable for similar services in the Austin area in an arms
length transaction; capital repairs or improvements made to the Building
which are covered by Landlord's warranties under the Lease or which are
performed to correct design or structural defects or to bring the Building
into conformity with applicable building codes in effect at the time of the
construction of the Building; expenses in connection with special services
for the exclusive benefit of another tenant in the Project.

                                     C-2
<PAGE>

                                   EXHIBIT D

                               TENANT FINISH-WORK

         1.       Landlord, at its sole cost and expense, shall complete
construction of the following components of the Premises: a) 14 VAV tenant
boxes installed on each floor (diffusers and duct work not installed), b)
perimeter fan-powered boxes installed along with related duct work and
diffusers c). mechanically suspended lay-in acoustical tile ceiling grid with
acoustical tile inventory stored on the floor of the Premises, d). recessed
fluorescent light fixtures, up to a maximum of one fixture per 120 rentable
square feet contained within the Premises, stored on the floor of the
Premises, and e). sprinkler heads installed pursuant to FBA 13 standards in
the Premises and other improvements set forth in Annex 1 to Exhibit D not
otherwise set forth in this work letter. All such construction shall be
completed by Landlord in a good and workmanlike manner and in accordance with
all applicable laws and regulations (including all handicap accessibility
laws).

         2.       On or before November 5, 1999, Tenant, at its sole cost and
expense, shall provide to Landlord for its approval final working drawings,
prepared by STG Partners, Inc., of all improvements that Tenant proposes to
install in the Premises; such working drawings shall include the partition
layout, ceiling plan, electrical outlets and switches, telephone outlets,
drawings for any modifications to the mechanical and plumbing systems of the
Building, and detailed plans and specifications for the construction of the
improvements called for under this Exhibit in accordance with all applicable
governmental laws, codes, rules, and regulations. Further, if any of Tenant's
proposed construction work will affect the Building's HVAC, electrical,
mechanical, or plumbing systems, then the working drawings pertaining thereto
shall be prepared by or reviewed by the Building's engineer of record, whom
Tenant shall at its cost engage for such purpose. As used herein, "WORKING
DRAWINGS" shall mean the final working drawings approved by Landlord, as
amended from time to time by any approved changes thereto, and "WORK" shall
mean all improvements to be constructed in accordance with and as indicated
on the Working Drawings. Approval by Landlord of the Working Drawings shall
not be a representation or warranty of Landlord that such drawings are
adequate for any use, purpose, or condition, or that such drawings comply
with any applicable law or code, but shall merely be the consent of Landlord
to the performance of the Work. Tenant shall, at Landlord's request, sign the
Working Drawings to evidence its review and approval thereof. All changes in
the Work must receive the prior written approval of Landlord, and in the
event of any such approved change Tenant shall, upon completion of the Work,
furnish Landlord with an accurate, reproducible "as-built" plan (e.g., sepia)
of the improvements as constructed, which plan shall be incorporated into
this Lease by this reference for all purposes. Landlord shall promptly review
and approve all such drawings and Landlord's approvals shall not be
unreasonably withheld, conditioned or delayed.

         3.       After the Working Drawings have been approved, Landlord
shall cause the Work to be performed in accordance with the Working Drawings
and all applicable laws, rules, regulations, permits, required governmental
consents and entitlements. The contractor, Tenant and the interior design
architect may inspect the Work as it progresses. Landlord shall be available,
and cause its subcontractors and architect to be reasonably available, to
Tenant or the interior design architect from time to time, on reasonable
prior notice, as necessary or desirable to review the Work. Landlord shall
submit to Tenant the proposed construction schedule for the Work. Landlord
shall promptly inform Tenant of any material delays encountered in completing
the Work and shall promptly deliver to Tenant, and consult with Tenant with
respect to, all revisions of the construction schedules therefor.

         4.       Tenant Delays means any delay by Tenant in providing, or
change by Tenant to, the Working Drawings, any delay because of any
specification by Tenant of materials or installations in addition to or other
than Landlord's standard finish-out materials, or any other delays caused by
Tenant in completion of the Work. No Tenant Delays pursuant to the
immediately preceding sentence shall be deemed to have occurred unless
Landlord notifies Tenant in writing within ten (10) days after the initial
cause of the delay of the specific delay; provided that the date the Tenant
Delay is deemed to commence shall be the date of the initial cause of the
delay, not the date of the notice. There shall further be excluded from the
number of days of Tenant Delays any days of delay which are caused by any act
or omission of Landlord, its agents or contractors, including the failure to
timely provide to Tenant and/or its agents and representatives complete
information regarding the Building necessary for the preparation of the
Working Drawings. Subject to Section 28 of the Lease, if the Premises are not
ready for occupancy and the Work is not Substantially Completed on the
scheduled Commencement Date for any reason other than Tenant Delays, then the
obligations of Landlord and Tenant shall continue in full force and Basic
Rental and Tenant's Proportionate Share of Basic Costs shall be abated until
the date the Work is Substantially Completed, which date shall be the
Commencement Date.

         5.       Tenant shall bear the entire cost of performing the Work
(including, without limitation, costs of design, construction, labor and
materials, additional janitorial services, related taxes and insurance costs,
all of which costs are herein collectively called the "TOTAL CONSTRUCTION
COSTS") in excess of the Construction Allowance (hereinafter defined). Upon
approval of the Working Drawings, Landlord shall obtain bids for the Work
from at least three (3) contractors (all of whom shall be approved by Tenant,
which approval shall not unreasonably withheld). Tenant hereby acknowledges
that Landlord's construction contract with the general contractor for the
Work will include a liquidated damages provision whereby the General
Contractor will be liable to Landlord for liquidated damages if the Work is
not Substantially Complete by February 1, 2000. Such liquidated damages shall
be in the

                                     D-1
<PAGE>

amount of One Thousand and 00/100 Dollars ($1,000.00) per day for each day after
February 1, 2000 until the Work is Substantially Complete; provided, however,
that the contract may provide that the general contractor shall not be required
to pay any such liquidated damages if the reason for the delay is caused by
Tenant Delays or inability to obtain necessary governmental permits or
approvals. Following selection of a contractor, Tenant shall promptly execute a
work order agreement prepared by Landlord which identifies such drawings,
itemizes the Total Construction Costs and sets forth the Construction Allowance,
and pay to an escrow account in an acceptable financial institution to Landlord
50% of the amount by which the estimated Total Construction Costs exceed the
Construction Allowance. Payments from both the escrow account and directly from
Tenant will be paid at times and within proportion of construction draws on the
Total Construction Costs. Upon Substantial Completion of the Work and before
Tenant occupies the Premises to conduct business therein, Tenant shall pay to
Landlord an amount equal to the the Total Construction Costs (as adjusted for
any approved changes to the Work), less 1). the amount of the payments already
made by Tenant, 2). the amount of the Construction Allowance, and 3). the cost
reasonably estimated by Landlord for completing all "punch list" items; finally,
upon completion of the punch list items, Tenant shall pay to Landlord any
additional costs incurred in completing the same.

         6.       Landlord shall provide to Tenant a construction allowance (the
"CONSTRUCTION ALLOWANCE") equal to the lesser of a). $24.00 per rentable square
foot in the Premises or b). the Total Construction Costs, as adjusted for any
approved changes to the Work.

         7.       Landlord or its affiliate shall manage the Work, make
disbursements required to be made to the contractor, and act as a liaison
between the contractor and Tenant and coordinate the relationship between the
Work, the Building, and the Building's systems. In consideration for Landlord's
construction management services, Tenant shall pay to Landlord a construction
management fee equal to three and one-half percent (3-1/2%) of the Total
Construction Costs.

         8.       Except as set forth in this Exhibit, Tenant accepts the
Premises in their newly constructed condition on the date that this Lease is
entered into.

         9.       Landlord shall ensure that the right to require work under
warranties of all subcontractors, manufacturers and suppliers relating to items
for which Tenant is responsible for the maintenance and repair thereof be
enforceable by Tenant and, upon Tenant's written request, Landlord shall provide
a copy of any such warranty to Tenant.

         10.      Landlord shall require that the contractor provide a final
cleaning of the Premises immediately before Tenant's acceptance of Substantial
Completion, consisting of cleaning to a condition expected for a good building
cleaning and maintenance program.

                                     D-2
<PAGE>

                             ANNEX 1 TO EXHIBIT D

     -    Finished entrance, elevators and elevator lobbies

     -    Finished restrooms

     -    Perimeter walls insulated

     -    Perimeter walls and column enclosures installed and ready for paint

     -    Ceiling grid installed

     -    2 ft. X 2 ft. Tegular ceiling tile stacked on the floor

     -    Finished stairways

     -    Public/common area lighting installed

     -    Tenant space light fixtures stocked on floor, 1:120 RSF

     -    14 VAV tenant boxes installed on each floor (diffusers and ductwork
          are not installed)

     -    Perimeter fan-powered boxes installed along with related ductwork and
          diffusers

     -    Automated "on-demand" systems for after-hours HVAC

     -    Electrical capacity: (1) 4 watts per RSF available for tenant' use at
          electrical closet; (2) upgrade capability to 6.5 watts per RSF,
          provided by City of Austin Power and Light

     -    Water and Wastewater service provided by City of Austin

     -    Telephone services provided by Southwestern Bell

     -    Conduit providing access to fiber optic network at front of property
          along street right-of-way as well as between buildings.

                                     D-3
<PAGE>

                                  EXHIBIT E

                                   PARKING

      Tenant shall be permitted to use one hundred thirty (130) undesignated
vehicular parking spaces (including visitor and handicap) and twenty (20)
reserved covered parking spaces in the surface parking lot (the "PARKING
FACILITIES") associated with the Building during the Term at no charge and
subject to such terms, conditions and regulations as are from time to time
applicable to patrons of the Parking Facilities.

                                     E-1
<PAGE>

                                    EXHIBIT F

                                EXTENSION OPTION

     Provided no Event of Default exists and Tenant is occupying not less than
50% of the Premises at the time of such election, Tenant may renew this Lease
for one (1) additional period of five (5) years on the same terms provided in
this Lease (except as set forth below), by delivering written notice of the
exercise thereof to Landlord not later than two hundred seventy (270) days
before the expiration of the Term. On or before the commencement date of the
extended Term, Landlord and Tenant shall execute an amendment to this Lease
extending the Term on the same terms provided in this Lease, except as follows:

1.   The Basic Rental payable for each month during such extended Term shall be
     the prevailing market rental rate in Austin's suburban office market, at
     the commencement of such extended Term, for space of equivalent quality,
     size, utility and location; rental concessions, tenant improvements and
     refurbishment allowances, moving allowances, architectural allowances,
     parking rental concessions, brokerage commissions, other inducements, and
     all other relevant factors, provided each of the foregoing applies to
     renewals or is adjusted to reflect the fact that the determination of
     market rent is for a renewal, with the length of the extended Term and the
     credit standing of Tenant to be taken into account;

2.   Tenant shall have no further renewal options unless expressly granted by
     Landlord in writing; and

3.   Landlord shall lease to Tenant the Premises in their then-current
     condition, and Landlord shall not provide to Tenant any allowances (e.g.,
     moving allowance, construction allowance, and the like) or other tenant
     inducements.

4.   If Landlord and Tenant fail to agree on the fair market rental value of the
     Leased Premises on or before one hundred eighty (180) days prior to the
     expiration of the term of this Lease, Landlord and Tenant shall cooperate
     to appoint an independent appraiser or broker to determine the fair market
     rental value. If Landlord and Tenant cannot agree upon such an appraiser or
     broker within one hundred sixty-five (165) days prior to the expiration of
     the term of the Lease, Landlord and Tenant, respectively, shall, within
     five (5) days, each appoint an independent appraiser or broker to determine
     the fair market rental value. If such independent appraisers or brokers
     cannot agree on upon the fair market rental value within fifteen (15) days
     after the expiration of such five (5) day period, such independent
     appraisers or brokers shall appoint a third independent appraiser or
     broker, whose determination shall be conclusively binding on Landlord and
     Tenant so long as it is not less than the lower or more than the higher of
     the determinations of the two other appraisers or brokers.

     Tenant's rights under this Exhibit shall terminate if (a) this Lease or
Tenant's right to possession of the Premises is terminated, (b) Tenant assigns
any of its interest in the Lease or sublets any portion of the Premises (except
to a Permitted Transferee) or sublets more than 50% of the Premises (other than
to a Permitted Transferee) for the remaining term of the Lease or (c) Tenant
fails to timely exercise its option under this Exhibit, time being of the
essence with respect to Tenant's exercise thereof.

                                     F-1
<PAGE>

                                  EXHIBIT G

                            FIRST RIGHT OF REFUSAL

                                  BUILDING 1

Subject to Subsection B below, Landlord hereby grants to Tenant for the term of
the Lease a right of first refusal for certain space in Building 1, Building 2
and Building 3 as described below, to be exercised in accordance with
Subsections A-1, A-2 and A-3 below, as applicable.

     A-1. At such time as Landlord receives any bona fide offers from a third
party to lease all or any one or more of the portions of the Building
depicted as "Space A-1," "Space A-2" and "Space A-3" on EXHIBIT A-1
(collectively, the "BUILDING 1 ROFR SPACE"), Landlord shall give Tenant
written notice of such offer and such notice shall: (i) specify all material
terms and conditions of such third party offer and (ii) contain an offer to
Tenant under the same terms and conditions as the third party offer and give
Tenant five (5) days (excluding holidays) to accept such offer. Should Tenant
fail to exercise its right to lease such available Building 1 ROFR Space
within such five (5) day (excluding holidays) period, Landlord shall have the
right to lease such Building 1 ROFR Space to such third party. If Landlord
shall then fail to lease such Building 1 ROFR Space to such third party or
its affiliates on substantially the same terms as contained in the offer
within six (6) months, this right of first refusal shall remain in effect
with respect to such space. If Tenant exercises its right of first refusal
with respect to the Building 1 ROFR Space, such space shall be added to the
Premises for all purposes of this Lease, except as provided in C below.
Notwithstanding the foregoing, Tenant's right of first refusal for the
portions of the Building depicted as "Space A-2" on EXHIBIT A-1 is subordinate
and subject to that right of first refusal for such space granted under that
certain Lease Agreement dated September 15, 1999 between Landlord and
AtOutcome, Inc. and Tenant's rights of first refusal for the portions of the
building depicted as "Space A-3" on Exhibit A-1 is subordinate and subject to
that renewal option for such space granted under said AtOutcome, Inc. Lease.
This right of first refusal contained in this Subsection A-1 is contingent on
there being no material adverse changes in Tenant's financial condition at
the time of exercise from Tenant's financial condition on August 31, 1999.
This First Right of Refusal shall be applicable to any space that becomes
available during the term and is intended to be a continuous first right of
refusal.

     A-2. At such time as Landlord receives any bona fide offers from a third
party to lease any portion of Building 2 which would result (either initially or
through the exercise of any expansion rights or rights of first refusal
contained in such offer) in twenty-five percent (25%) or less of Building 2
remaining unleased (the "BUILDING 2 ROFR SPACE"), Landlord shall give Tenant
written notice of such offer and such notice shall (i) specify all material
terms and conditions of such third party offer and (ii) contain an offer to
Tenant under the same terms and conditions as the third party offer and give
Tenant five (5) days (excluding holidays) to accept such offer. Should Tenant
fail to exercise its right to lease such available Building 2 ROFR Space within
such five (5) day (excluding holidays) period, Landlord shall have the right to
lease such Building 2 ROFR Space to such third party and Tenant's right of first
refusal under this subsection A-2 shall be subject and subordinate to any right
of first refusal, expansion right and/or renewal granted under such lease to
such third party (provided such rights were contained in the offer presented to
Tenant). If Landlord shall fail to lease such Building 2 ROFR Space to such
third party or its affiliates on substantially the same terms as contained in
the offer within six (6) months then Tenant's right of first refusal with
respect to that Building 2 ROFR Space shall remain in effect with respect to
such space. The right of first refusal contained in this Subsection A-2 (i) is
contingent on there being no material adverse changes in Tenant's financial
condition at the time of exercise from Tenant's financial condition on August
31, 1999 and (ii) shall apply only to the initial lease up of Building 2 (i.e.,
once a space has been leased, the right of first refusal granted to Tenant shall
no longer apply to it).

     A-3. At such time as Landlord receives any bona fide offers from a third
party to lease any portion (the "BUILDING 3 ROFR SPACE") of the next speculative
building for office use built by Landlord in the Development ("BUILDING 3"),
Landlord shall give Tenant written notice of such offer and such notice shall
(i) specify all material terms and conditions of such third party offer and (ii)
contain an offer to Tenant under the same terms and conditions as the third
party offer and give Tenant five (5) days (excluding holidays) to accept such
offer. Determination of the speculative building status will be as follows:
within thirty (30) days after a building permit for shell construction is
granted, Landlord shall declare if the building is a build to suit. Should
Tenant fail to exercise its right to lease such available Building 3 ROFR Space
within such five (5) day (excluding holidays) period, Landlord shall have the
right to lease the Building 3 ROFR Space to such third party and Tenant's right
of first refusal under this Subsection A-3 shall be subordinate and subject to
any right of first refusal, expansion right and/or renewal right granted under
such lease to such third party (provided such right was contained in the offer
presented to Tenant). If Landlord shall fail to lease such Building 3 ROFR Space
to such third party or its affiliates on substantially the same terms as
contained in the offer within six (6) months, this right of first refusal shall
remain in effect with respect to such space. Notwithstanding the foregoing,
Tenant's right of first refusal under this Subsection A-3 shall (x) only be
applicable to space in a speculative building built by Landlord for office use
(i.e. shall not apply to any space in a build-to-suit building or building used
for non-office uses) (y) be effective only if prior to the date Landlord
receives the third party offer in question Tenant provides audited financial
statements (if available, and if not, unaudited statements certified by Tenant's
chief financial officer) to Landlord showing either total revenues in excess of
$40,000,000.00 for the previous two quarters or total revenues in excess of
$80,000,000.00 for the previous four quarters, and (z) apply only to the initial
lease up of Building 3 (i.e., once a space has been leased, the right of first
refusal granted to Tenant shall no longer apply to it).

                                     G-1
<PAGE>

     B.   Tenant's rights of first refusal as set forth in Subsections A-1, A-2
and A-3 above are subject to the conditions that: (i) on the date that Tenant
delivers its notice exercising its right of first refusal, no Event of Default
exists, (ii) Tenant shall not have assigned the Lease, or sublet any portion of
the Premises (except to a Permitted Transferee) and (iii) at the time that the
third party offer is received by Landlord, Tenant must have provided Landlord
with the financial information necessary to meet the respective financial
requirements in Subsection A-1, A-2 or A-3 as applicable. Tenant shall be deemed
to have met the requirement in (iii) above as it relates to Subsection A-1 or
A-2, so long as Tenant delivers to Landlord quarterly financial statements
showing no material adverse change in Tenant's financial condition since August
31, 1999.

     C.   Promptly after Tenant's exercise of any right of first refusal with
respect to the Building as provided herein, Landlord shall execute and deliver
to Tenant an amendment to the Lease to reflect changes in the Premises, Basic
Rental, Tenant's Proportionate Share and any other appropriate terms changed by
the addition of the ROFR Space. Within 10 days thereafter, Tenant shall execute
and return the amendment; provided that the term for any such Building 1 ROFR
Space shall be the same as contained in the offer (i.e., it will not be
coterminous with the Lease).

     D.   Notwithstanding anything to the contrary contained herein, if Tenant
exercises its right of first refusal as to space in Building 2 or 3, then within
fifteen (15) days after such exercise, Landlord and Tenant shall enter into a
new lease for such space on the same form as this Lease except for any changes
necessary to reflect the business terms contained in the accepted third party
offer and to reflect differences in the Buildings. Each such lease will contain
a signage provision similar to Section 27 of this Lease, except that Tenant's
rights to monument signage (like building signage) shall only be triggered if
another tenant in the building in question (which tenant leases less space than
Tenant) is permitted to have monument signage, in which case the size of the
respective sign panels shall be based proportionately on the relative square
footage of each tenant's space.

     E.   If any individual employed by Tenant's broker is working on a
competing project in southwest Austin (including the Terrace), Tenant agrees to
not disclose any terms and conditions of any offer received from Landlord under
this Exhibit to that individual for a period of six (6) months after such offer.

     F.   Tenant shall not disclose the provisions and conditions of this right
of first refusal to any person or entity except to persons or entities providing
counsel or assistance to Tenant in connection with this Lease, including,
without limitation, attorneys, engineers, architects, and brokers, and as
required by valid court order or subpoena and disclosures required by the
Securities and Exchange Commission, federal securities law, current and future
lenders, and current and future investors.

                                     G-2
<PAGE>

                                    EXHIBIT H

WHEN RECORDED, RETURN TO:

Lynda Zimmerman, Esq.
Winstead Sechrest & Minick P.C.
5400 Renaissance Tower
1201 Elm Street
Dallas, Texas 75270

            SUBORDINATION, ATTORNMENT AND NON-DISTURBANCE AGREEMENT

     This SUBORDINATION, ATTORNMENT AND NON-DISTURBANCE AGREEMENT ("AGREEMENT")
is made and entered into as of October 29, 1999 by and between COMERICA
BANK-TEXAS, a state banking association ("BENEFICIARY"); STRATUS 7000 WEST JOINT
VENTURE, a Texas joint venture ("LESSOR"); and SILICON LABORATORIES, INC., a
Delaware Corporation, ("LESSEE").

                                  WITNESSETH:

     WHEREAS, Beneficiary is the owner and holder of that certain Promissory
Note ("NOTE") dated April 9, 1999, in the principal sum of SIX MILLION SIX
HUNDRED THOUSAND AND NO/100 DOLLARS ($6,600,000.00), secured by that certain
Deed of Trust ("DEED OF TRUST"), dated of even date with the Note, executed
by Lessor to a trustee in favor of Beneficiary, recorded on April 16, 1999,
as Document No. 1999009453 in the Offical Public Records of Travis County,
Texas, which Deed of Trust constitutes a lien on the land described in
EXHIBIT A attached hereto and incorporated herein by reference for all
purposes and the improvements now or hereafter located thereon ("PROPERTY");
and

     WHEREAS, Lessee is the holder of a leasehold estate in and to all or a
portion of the Property (the property which is the subject of such leasehold
estate being referred to as the "DEMISED PREMISES") pursuant to the terms of
that certain lease agreement ("LEASE") dated October 27, 1999, and executed by
and between Lessee, as the tenant, and Lessor, as the landlord; and

     WHEREAS, Lessor, Lessee and Beneficiary desire to confirm their
understandings with respect to the Lease and the Deed of Trust.

     NOW, THEREFORE, in consideration of the mutual and dependent covenants and
agreements herein contained, and for other good and valuable consideration, the
receipt and sufficiency of which are hereby acknowledged and confessed, the
parties hereto agree and covenant as follows:

     1.   SUBORDINATION. Subject to the terms of this Agreement, the Lease now
is, and shall at all times continue to be, subject, inferior and subordinate in
each and every respect to the lien of the Deed of Trust and to any and all
renewals, amendments, modifications, extensions, substitutions, replacements,
increases and/or consolidations of the Deed of Trust and/or Note, and the lien
of the Deed of Trust, and any and all renewals, amendments, modifications,
extensions, substitutions, replacements, increases and/or consolidations of the
Deed of Trust and/or the Note, shall be and remain, in each and every respect,
prior and superior to the Lease. This Agreement shall be the whole and only
agreement with regard to the subordination of the Lease to the lien of the Deed
of Trust and shall supersede and cancel, insofar as same may affect the priority
between the Deed of Trust and the Lease, any prior agreements or provisions
relating to the subordination of the Lease to the lien of the Deed of Trust,
including, without limitation, those provisions, if any, contained in the Lease
which provide for the subordination thereof to the lien of any deed of trust,
mortgage or other security agreement. Nothing herein contained shall be deemed
or construed as limiting or restricting the enforcement by Beneficiary of any of
the terms, covenants, provisions or remedies specified in the Deed of Trust,
whether or not consistent with the Lease, including (without

<PAGE>

limitation) any rights, remedies, privileges and recourses of Beneficiary with
respect to insurance proceeds and condemnation awards with respect to the
Demised Premises or the Property. The Lease is herein made subordinate to the
aforementioned instruments only and not to any other encumbrances placed upon or
against the Demised Premises. This provision is declared by Beneficiary and
Lessee to be effective and self-operative, without the execution of any further
instruments on the part of any of the parties hereto.

     2.   PURCHASER. As used herein, the term "PURCHASER" shall be deemed to
include Beneficiary and any of its successors and assigns, including anyone who
shall have succeeded to Lessor's interest in the Demised Premises by, through or
under judicial foreclosure sale, non-judicial foreclosure sale or other similar
proceedings brought pursuant to the Deed of Trust, deed in lieu of such
foreclosure, other proceedings brought by Beneficiary under or with respect to
the Note or Deed of Trust, or otherwise.

     3.   ATTORNMENT. If the interests of Lessor in and to the Demised Premises
become owned by Beneficiary or another Purchaser by reason of judicial
foreclosure, non-judicial foreclosure by the trustee under the Deed of Trust,
other proceedings brought by Beneficiary or Purchaser or by any other manner,
including, but not limited to, Beneficiary's exercise of its rights under any
collateral assignment(s) of leases and rents, whereby Purchaser succeeds to the
interest of the Lessor under the Lease, Lessee shall be bound to Purchaser in
accordance with all of the terms, covenants and conditions of the Lease for the
balance of the term thereof and any extension thereof duly exercised by Lessee
with the same force and effect as if Purchaser were the lessor under the Lease.
Lessee does hereby attorn to Purchaser, as its lessor, which attornment shall be
effective and self-operative, without the execution of any further instruments
on the part of any of the parties hereto, immediately upon Purchaser's
succeeding to the interest of the Lessor under the Lease; provided, however,
that Lessee shall be under no obligation to pay rent to Purchaser until Lessee
receives written notice from Purchaser that it has succeeded to the interest of
the Lessor under the Lease, and upon receipt of such notice, Lessee shall pay to
Purchaser all rental and other payments required under the Lease for the
duration of the term of the Lease and any extensions thereof duly exercised by
Lessee and lessor hereby consents to such payments. The respective rights and
obligations of Lessee and Purchaser upon such attornment, to the extent of the
then remaining balance of the term of the Lease and any extension thereof duly
exercised, shall be and are the same as now set forth therein, it being the
intention of the parties hereto for this purpose to incorporate the Lease in
this Agreement by reference, with the same force and effect as if expressly set
forth herein.

     4.   NON-DISTURBANCE. In the event of a foreclosure of the lien of the
Deed of Trust, so long as Lessee is not in default (beyond any period given
in the Lease to Lessee to cure such default) in the payment of rent or in the
performance of any of the terms, covenants or conditions of the Lease on
Lessee's part to be performed, Lessee's possession, use and occupancy of the
Demised Premises pursuant to the Lease shall not be extinguished or
terminated by such foreclosure nor interfered with or disturbed by Purchaser
during the term of the Lease and any extension thereof duly exercised by
Lessee. If at, or subsequent to, the time that Purchaser shall acquire, in
whatever manner, title to the Property or Lessor's title or interest in the
Demised Premises (subject to the Lease), or from time to time thereafter, any
default exists or occurs under the Lease, then Purchaser shall be entitled to
exercise or enforce any and all rights, privileges, remedies and recourses
which it may have against Lessee under or pursuant to the Lease or other
applicable law (including, without limitation, the termination of the Lease,
the dispossession of Lessee from the Demised Premises, or the prosecution of
an action for breach of the Lease), notwithstanding the provisions of this
Agreement.

     5.   PURCHASER'S OBLIGATIONS. If Purchaser shall succeed to the interest of
Lessor under the Lease, Purchaser shall be bound to Lessee under all of the
terms, covenants and conditions of the Lease and shall recognize and observe all
of Lessee's rights and privileges under this Lease; provided, however, that
Purchaser shall not be:

          (a)  liable for any act or omission of any prior lessor (including
     Lessor) under the Lease; or

          (b)  subject to any offsets or defenses which Lessee might have
     against any prior lessor (including Lessor) under the Lease; or

                                                                          page 2

<PAGE>

          (c)  bound by any rent, additional rent, advance rent or other
     monetary obligations which Lessee might have paid for more than the current
     month to any prior lessor (including Lessor) under the Lease and which is
     not delivered or paid to Purchaser at the time of Purchaser's succession to
     title to the Demised Premises, and all such rent or other monetary
     obligations shall remain due and owing, notwithstanding such advance
     payment, and with respect to which Lessee agrees to look solely to Lessor
     for refund or reimbursement; or

          (d)  bound by any security deposit of any type or advance rental
     deposit made by Lessee under the Lease which is not delivered or paid to
     Purchaser at the time of Purchaser's succession to title to the Demised
     Premises, and with respect to which Lessee agrees to look solely to Lessor
     for refund or reimbursement; or

          (e)  bound by any amendment, modification, supplementation,
     termination or cancellation of the Lease made without Beneficiary's or
     Purchaser's prior written consent and approval; or

          (f)  required to complete the construction of any improvements or
     otherwise perform the obligations of Lessor under the Lease in the event
     that Purchaser acquires title to the Property prior to full completion and
     acceptance by Lessee of improvements required under the Lease; or

          (g)  liable or responsible under or pursuant to the terms of the Lease
     after it ceases to own an interest in or to the Demised Premises.

     6.   REPRESENTATIONS. Lessor and Lessee represent, warrant and certify to
Beneficiary (and Purchaser), as of the date hereof, as follows:

          (a)  the Lease is presently in full force and effect;

          (b)  the Lease has not been cancelled, terminated, modified, amended,
     supplemented, replaced, restated or otherwise changed, either orally or in
     writing, except as herein expressly provided;

          (c)  all conditions or requirements specified in the Lease that could
     have been satisfied as of the date hereof have been fully satisfied;

          (d)  no rent under the Lease has been paid for more than the current
     rental period established in the Lease;

          (e)  no default (or any event, condition or circumstance, which with
     notice, grace or lapse of time could constitute a default) exists under
     said Lease;

          (f)  Lessee, as of this date, has no charge, lien or claim of offset
     under said Lease or otherwise against rents or other charges due or to
     become due under the Lease;

          (g)  the Lease constitutes the entire agreement between the Lessee and
     Lessor and that Purchaser shall have no liability or responsibility with
     respect to any security deposit or advance rental deposit made by the
     Lessee except to the extent actually delivered and paid to Purchaser
     concurrently with Purchaser's succession in interest to the Demised
     Premises;

          (h)  the only persons or entities in possession of the Demised
     Premises or having any right to the possession, use or occupancy of the
     Demises Premises (other than the record owner or holders of recorded
     easements) is Lessee; and

          (i)  Lessee has no right or interest in or under any contract, option
     or agreement (other than as shown in the Lease) involving the sale or
     transfer of the Demised Premises or the expansion of the Demised Premises
     or extension of the term of the Lease.

Lessor and Lessee further agree to execute and deliver to Beneficiary, promptly
upon request of Beneficiary and without charge, a written updated certification
of the representations, warranties and

                                                                          page 3

<PAGE>

certifications provided in this SECTION 6 to the extent then accurate (or if any
are not accurate, an explanation of the circumstances of any inaccuracy).

     7.   NEGATIVE COVENANTS. In the absence of the prior written consent of
Beneficiary (or Purchaser), Lessee agrees not to do any of the following: (a)
prepay the rent or other monetary obligations under the Lease for more than one
(1) month in advance, (b) enter into any agreement, whether oral or written,
with the Lessor to amend, modify, supplement, replace, restate or otherwise
change the Lease, (c) voluntarily surrender the Demised Premises or terminate
the Lease except as expressly provided for in the Lease to the contrary, and (d)
sublease or assign all or any portion of the Demised Premises or the Lease
except as expressly provided for in the Lease to the contrary.

     8.   DEFAULT. In the event Lessor shall fail to perform or observe any of
the terms, conditions or agreements in the Lease, Lessee shall, as a condition
precedent to any action with respect to such default under the Lease, give
written notice thereof to Beneficiary and Beneficiary shall have the right (but
not the obligation) to cure such default. Lessee shall not take any action with
respect to such default under the Lease, including without limitation any action
in order to terminate, rescind or avoid the Lease or to withhold any rent or
other monetary obligations thereunder except as expressly provided for in the
Lease to the contrary, for a period of thirty (3 0) days after receipt of such
written notice by Beneficiary; provided, however, that in the case of any
default which cannot with diligence be cured within said thirty (30) day period,
if Beneficiary shall proceed promptly to cure such default and thereafter
prosecute the curing of such default with diligence and continuity, the time
within which such default may be cured shall be extended for such period as may
be necessary to complete the curing of such default with diligence and
continuity.

     9.   NOTICES. All notices or other communications required or permitted to
be given pursuant to this Agreement shall be in writing and shall be considered
as properly given if (i) mailed by first class United States mail, postage
prepaid, registered or certified with return receipt requested; (ii) by
delivering same in person to the intended addressee; or (iii) by delivery to an
independent third party commercial delivery service for same day or next day
delivery and providing for evidence of receipt at the address of the intended
addressee. Notice so mailed shall be effective upon its deposit with the United
States Postal Service or any successor thereto; notice sent by a commercial
delivery service shall be effective upon delivery to such commercial delivery
service; notice given by personal delivery shall be effective only if and when
received by the addressee; and notice given by other means shall be effective
only if and when received at the office or designated address of the intended
addressee. For purposes of notice, the addresses of the parties shall be as set
forth below; provided, however, that either party shall have the right to change
its address for notice hereunder to any other location within the continental
United States by the giving of thirty (30) days notice to the other party in the
manner set forth herein.

          Beneficiary:     Comerica Bank-Texas
                           1601 Elm Street, 2nd Floor
                           Dallas, Texas 75201
                           Attention: National Real Estate Services

          Lessor:          Stratus 7000 West Joint Venture
                           98 San Jacinto Boulevard
                           Suite 220
                           Austin, Texas 78701
                           Attn: William H. Armstrong, III

          Lessee:          Silicon Laboratories, Inc.
                           4635 Boston Lane
                           Austin, Texas 78735

     10.  COUNTERPARTS. To facilitate execution, this instrument may be
executed in as many counterparts as may be convenient or required. It shall not
be necessary that the signature or acknowledgment of, or on behalf of, each
party, or that the signature of all persons required to bind any party, or the
acknowledgment of such party, appear on each counterpart. All counterparts
shall collectively constitute a single instrument. It shall not be necessary in
making proof of this instrument to produce or account for more than a single
counterpart containing the respective

                                                                          page 4

<PAGE>

signatures of, or on behalf of, and the respective acknowledgments of, each of
the parties hereto. Any signature or acknowledgment page to any counterpart may
be detached from such counterpart without impairing the legal effect of the
signatures or acknowledgments thereon and thereafter attached to another
counterpart identical thereto except having attached to it additional signature
or acknowledgment pages.

     11.  AMENDMENT. This Agreement may not be modified orally or in any manner
other than by an agreement, in writing, signed by the parties hereto or their
respective successors in interest.

     12.  SUCCESSORS. This Agreement shall inure to the benefit of and be
binding upon the parties hereto, their successors and assigns.

     13.  REMEDIES CUMULATIVE. All remedies provided for herein are cumulative
and shall be in addition to, but not in lieu of, any and all other rights and
remedies provided by law and by any and all other agreements between Beneficiary
and either Lessor or Lessee.

     14.  FURTHER ASSURANCES. At the request of Beneficiary, Lessor and Lessee
shall execute, acknowledge, and deliver such other documents and/or instruments
as may be reasonably required by Beneficiary in order to effectuate the intent
and purpose of this Agreement; provided, however, that no such document or
instrument shall modify the rights and obligations of Lessor and Lessee as
provided herein.

     15.  ATTORNEYS' FEE. The prevailing party in any action brought against
the other parties hereto to enforce any rights, obligations or duties under this
Agreement shall be entitled to recover from the nonperforming party the
prevailing party's reasonable costs and expenses (including attorneys' fees)
incurred in connection with the enforcement hereof

     16.  TERMINATION. This Agreement shall be of no further force and effect
and shall become null and void upon the recording in the applicable records of
Beneficiary's written release of the lien of the Deed of Trust.

     17.  NO ORAL AGREEMENTS. THIS AGREEMENT EMBODIES THE FINAL, ENTIRE
AGREEMENT OF THE PARTIES HERETO AND SUPERSEDES ANY AND ALL PRIOR COMMITMENTS,
AGREEMENTS, REPRESENTATIONS, AND UNDERSTANDINGS, WHETHER WRITTEN OR ORAL,
RELATING TO THE SUBJECT MATTER HEREOF. THIS AGREEMENT IS INTENDED BY THE PARTIES
HERETO AS A FINAL AND COMPLETE EXPRESSION OF THE TERMS OF THIS AGREEMENT AND NO
COURSE OF DEALING BETWEEN THE PARTIES HERETO, NO COURSE OF PERFORMANCE, NO TRADE
PRACTICES, AND NO EVIDENCE OF PRIOR, CONTEMPORANEOUS OR SUBSEQUENT ORAL
AGREEMENTS OR DISCUSSIONS OR OTHER EXTRINSIC EVIDENCE OF ANY NATURE SHALL BE
USED TO CONTRADICT, VARY, SUPPLEMENT OR MODIFY ANY TERM OF THIS AGREEMENT. THERE
ARE NO ORAL AGREEMENTS BETWEEN THE PARTIES HERETO.

     IN WITNESS WHEREOF, the parties hereto have executed this Agreement as of
the day and year first above written.

                              BENEFICIARY:

                              COMERICA BANK-TEXAS,
                              a state banking association

                              By: /s/ Sherry R. Layne
                              Name:  Sherry R. Layne
                              Title:  Vice President

                                                                          page 5

<PAGE>

                              LESSOR:

                              STRATUS 7000 WEST JOINT VENTURE,
                              a Texas joint venture

                              By:   Stratus 7000 West, Ltd.,
                                    a Texas limited partnership,
                                    Joint Venturer

                                    By:   STRS L.L.C.,
                                          a Delaware limited liability company,
                                          Its General Partner

                                          By:   Stratus Properties, Inc.,
                                                a Delaware corporation,
                                                Its Sole Member

                                            By: /s/ William H. Armstrong, III
                                            Name:  William H. Armstrong, III
                                            Title: President and Chief Executive
                                                   Officer

                              By:   OLY LANTANA, L.P., a Texas limited
                                    partnership, Joint Venturer

                                    By:   OLY LANTANA, L.P., a Texas limited
                                          liability company, its General Partner

                                            By: /s/ Hal R. Hall
                                            Name:  Hal R. Hall
                                            Title:______________________________

                              LESSEE:

                              SILICON LABORATORIES, INC.
                              a Delaware corporation

                              By: /s/ Navdeep S. Sooch
                              Name:  Navdeep S. Sooch
                              Title:  Chairman & CEO

STATE OF TEXAS

COUNTY OF DALLAS

    This instrument was ACKNOWLEDGED before me on the 4th day of November 1999
by Shery R. Layne, the Vice President of COMERICA BANK-TEXAS, a state banking
association, on behalf of said association.

[SEAL]                                          /s/ Kristine K. Finn
                                               -------------------------------
                                               Notary Public, State of Texas
My Commission Expires:
                                               _______________________________
______________________                         Printed Name of Notary Public

                                                                          Page 6

<PAGE>

STATE OF TEXAS      Section
                    Section
COUNTY OF TRAVIS    Section
         --------

     The foregoing instrument was ACKNOWLEDGED before me this 29th day of
October, 1999, by William H. Armstrong, III, the President and Chief Executive
Officer of STRATUS PROPERTIES, INC., a Delaware corporation and the Sole Member
of STRS L.L.C., a Delaware limited liability company and the General Partner of
STRATUS 7000 WEST, LTD., a Texas limited partnership and Operating Partner of
STRATUS 7000 WEST JOINT VENTURE, a Texas joint venture, on behalf of each of
said entities.

[SEAL]                                   /s/ Mary Bradley
                                       ----------------------------------------
                                       Notary Public, State of Texas
My Commission Expires:
                                         MARY BRADLEY
                                       ----------------------------------------
Jan. 16, 2002                          (Printed Name of Notary Public)
-----------------

STATE OF TEXAS      Section
                    Section
COUNTY OF DALLAS    Section
         --------

     The foregoing instrument was ACKNOWLEDGED before me this 2 day of
November, 1999, by Hal Hall, the Vice President of OLY Lantana, G.P., L.L.C.,
general partner of OLY Lantana, L.P, a Texas limited partnership, Joint
Venturer, of STRATUS 7000 WEST JOINT VENTURE, on behalf of said entities.

[SEAL]                                   /s/ Kerry A. Nunn
                                       ----------------------------------------
                                       Notary Public, State of Texas
My Commission Expires:
                                         Kerry A. Nunn
                                       ----------------------------------------
October 6, 2002                        (Printed Name of Notary Public)
-----------------

                                                                         Page 7
<PAGE>

STATE OF TEXAS      Section
                    Section
COUNTY OF TRAVIS    Section
         --------

     This instrument was ACKNOWLEDGED before me on the 29th day of October,
1999, by NAVDEEP S. SOOCH, the Chairman and CEO of SILICON LABORATORIES, INC.,
a DELAWARE Corporation on behalf of corporation.

[SEAL]                                   /s/ Lynette L. Herr
                                       ----------------------------------------
                                       Notary Public, State of Texas
My Commission Expires:
                                         Lynette L. Herr
                                       ----------------------------------------
April 27, 2002                         Printed Name of Notary Public
-----------------

EXHIBIT LIST

Exhibit A - Legal Description

                                                                         Page 8
<PAGE>

                                  EXHIBIT I

                     LETTER OF CREDIT PRO FORMA WORDING

                               PAGE ONE OF TWO

               (FOR LETTER OF CREDIT ISSUED BY IMPERIAL BANK)

APPLICANT:

BENEFICIARY:

AMOUNT:

EXPIRY DATE AND PLACE FOR PRESENTATION OF DOCUMENTS: [need date] IMPERIAL BANK
INTERNATIONAL DIVISION, 2015 MANHATTAN BEACH BLVD., 2ND FLR., REDONDO BEACH,
CA 90278

CREDIT IS AVAILABLE WITH IMPERIAL BANK INTERNATIONAL DIVISION AGAINST PAYMENT
OF DRAFTS DRAWN AT SIGHT ON IMPERIAL BANK INTERNATIONAL DIVISION, 2015 MANHATTAN
BEACH BLVD., 2ND FLR., REDONDO BEACH, CA 90278

DOCUMENTS REQUIRED:

1. THE ORIGINAL OF THIS STANDBY LETTER OF CREDIT AND AMENDMENT(S) IF ANY.

2. BENEFICIARY'S STATEMENT PURPORTEDLY SIGNED BY AN AUTHORIZED OFFICER
CERTIFYING THAT [APPLICANT' NAME] IS IN DEFAULT OR THAT AN EVENT OF DEFAULT HAS
OCCURRED UNDER ONE OR MORE OF THE TERMS OF THAT CERTAIN LEASE AGREEMENT DATED
[GIVE DATE] THAT EXISTS BETWEEN [APPLICANT'S NAME] AND [BENEFICIARY'S NAME] AND
THAT ANY APPLICABLE CURE PERIOD HAS LAPSED WITHOUT REMEDY.

SPECIAL CONDITIONS:

ALL INFORMATION REQUIRED UNDER DOCUMENT REQUIREMENT NO. 2 WHETHER INDICATED BY
BLANKS, BRACKETS OR OTHERWISE, MUST BE COMPLETED AT THE TIME OF DRAWING.

ALL SIGNATURES MUST BE MANUALLY EXECUTED IN ORIGINALS.

PARTIAL DRAWINGS MAY BE MADE UNDER THIS LETTER OF CREDIT, PROVIDED, HOWEVER,
THAT EACH SUCH DEMAND THAT IS PAID BY US SHALL REDUCE THE AMOUNT AVAILABLE UNDER
THIS LETTER OF CREDIT.

IT IS A CONDITION OF THIS STANDBY LETTER OF CREDIT THAT IT SHALL BE DEEMED
AUTOMATICALLY EXTENDED WITHOUT AMENDMENT FOR ONE YEAR PERIODS FROM THE PRESENT
EXPIRATION DATE HEREOF, UNLESS THIRTY (30) DAYS PRIOR TO ANY SUCH DATE, WE SHALL
NOTIFY YOU IN WRITING BY CERTIFIED MAIL OR COURIER SERVICE AT THE ABOVE LISTED
ADDRESS THAT WE ELECT NOT TO CONSIDER THIS IRREVOCABLE LETTER OF CREDIT RENEWED
FOR ANY SUCH ADDITIONAL PERIOD. UPON RECEIPT BY YOU OF SUCH NOTICE, YOU MAY DRAW
HEREUNDER BY MEANS OF YOUR DRAFT(S) ON US AT SIGHT ACCOMPANIED BY YOUR ORIGINAL
SIGNED STATEMENT WORDED AS FOLLOWS: [beneficiary] HAS RECEIVED NOTICE FROM
IMPERIAL BANK THAT THE EXPIRATION DATE OF LETTER OF CREDIT NO. [INSERT L/C NO.]
WILL NOT BE EXTENDED FOR AN ADDITIONAL PERIOD. AS OF THE DATE OF THIS DRAWING,
[beneficiary] HAS NOT RECEIVED A SUBSTITUTE LETTER OF CREDIT OR OTHER INSTRUMENT
ACCEPTABLE TO [beneficiary] AS SUBSTITUTE FOR IMPERIAL BANK LETTER OF CREDIT NO.
[INSERT L/C NO.].

NOTWITHSTANDING THE ABOVE, THE FINAL EXPIRATION DATE SHALL BE MMDDYY.

ALL DRAFTS AND DOCUMENTS REQUIRED UNDER THIS LETTER OF CREDIT MUST BE MARKED:
"DRAWN UNDER IMPERIAL BANK LETTER OF CREDIT NO. [INSERT L/C NO.]"

ALL DOCUMENTS ARE TO BE DISPATCHED IN ONE LOT BY COURIER SERVICE TO IMPERIAL
BANK INTERNATIONAL DIVISION, 2015 MANHATTAN BEACH BLVD., 2ND FLR., REDONDO
BEACH, CA 90278

                                     G-4
<PAGE>

                                  EXHIBIT I

                      LETTER OF CREDIT PRO FORMA WORDING

                               PAGE TWO OF TWO

THIS LETTER OF CREDIT SETS FORTH IN FULL THE TERMS OF OUR UNDERTAKING AND SUCH
UNDERTAKING SHALL NOT BE IN ANY WAY MODIFIED, AMENDED OR AMPLIFIED BY REFERENCE
TO ANY DOCUMENT, INSTRUMENT OR AGREEMENT REFERRED TO HEREIN OR IN WHICH THIS
LETTER OF CREDIT IS REFERRED TO OR TO WHICH THIS LETTER OF CREDIT RELATES, AND
ANY SUCH REFERENCE SHALL NOT BE DEEMED TO INCORPORATE HEREIN BY REFERENCE ANY
DOCUMENT, INSTRUMENT OR AGREEMENT.

WE HEREBY ENGAGE WITH YOU THAT ALL DRAFTS DRAWN UNDER AND IN COMPLIANCE WITH THE
TERMS OF THIS CREDIT WILL BE DULY HONORED IF DRAWN AND PRESENTED FOR PAYMENT AT
THIS OFFICE ON OR BEFORE THE EXPIRATION DATE OF THIS CREDIT.

EXCEPT SO FAR AS OTHERWISE EXPRESSLY STATED, THIS CREDIT IS SUBJECT TO THE
"UNIFORM CUSTOMS AND PRACTICE FOR DOCUMENTARY CREDITS" (1993 REVISION)
INTERNATIONAL CHAMBER OF COMMERCE (PUBLICATION NO. 500).

                                     G-4
<PAGE>

                                  EXHIBIT J

                            CONFIDENTIAL AGREEMENT

                    DISCLOSURE OF CONFIDENTIAL INFORMATION

This agreement, effective this 27th day of October 1999 by and between Silicon
Laboratories Inc., a corporation organized under the laws of the State of
Delaware, and having its principal place of business at 4635 Boston Lane,
Austin, TX 78735, and Stratus 7000 West Joint Venture, a joint venture organized
under the laws of Texas and having its principal place of business at Stratus
Properties Inc. 98 San Jacinto, Suite 220 Austin, Texas 78701 hereinafter
referred to as the "party" or the "parties." Whereas, the parties desire to
discuss with each other information relating to historical financial
information, financial forecasts, business plans, staffing levels and future
product development activities.

Now, therefore, in consideration of the aforesaid disclosures and further in
consideration of the rights and obligations hereinafter set forth, it is hereby
agreed as follows:

I.   Each party shall hold in confidence any and all confidential information
     disclosed by the other, with regard to the above part numbers and shall
     exercise the same degree of diligence with respect to the dissemination of
     such information as that exercised with respect to their own confidential
     information which they do not want disclosed.

II.  Each party agrees not to disclose to any third party confidential
     information disclosed by the other or to offer for sale or otherwise
     dispose of to any third party devices (or information relating to the
     subject matter) utilizing any of the confidential information (unless
     otherwise authorized in writing).

Information disclosed hereunder shall not be deemed to be confidential if:

          A.   The information was generally available to the public at the time
               of disclosure to the receiving party; or
          B.   The information hereafter becomes generally available to the
               public, except as the result of unauthorized disclosure by the
               receiving party; or
          C.   The party disclosing the information agrees, in writing, that it
               can be disclosed, by the receiving party to a third party; or
          D.   The information is known to the receiving party and documented in
               writing prior to its receipt, is not subject to a non-disclosure
               commitment on the part of the receiving party, and the receiving
               party informs the disclosing party of such facts at the time of
               the disclosure; or
          E.   The information is or becomes available on an unrestricted basis
               to a third party from the disclosing party or from someone acting
               under its control (except that a corporate subsidiary of either
               party shall not be deemed a "third party" hereunder).

In the event the receiving party is obligated to produce such information, as a
result of court order or pursuant to governmental action and the transmitting
party shall have been given notice and an opportunity to appear and object to
such disclosure but is unsuccessful, then the receiving party may produce such
information as is required by the court order or governmental action to such
third party.

III. The disclosing party's confidential information shall be made available
     only to those employees of the receiving party who have a reasonable need
     for such information.

IV.  The parties agree not to utilize any such confidential information received
     under this Agreement in the manufacture of articles sold or offered for
     sale to anyone other than the disclosing party without prior written
     consent of the disclosing party, subject to the same exceptions set forth
     in Paragraph II above.

V.   Any confidential disclosure, if made orally, shall be identified as
     confidential prior to disclosure and shall be promptly confirmed in writing
     by the disclosing party, within 30 days, if the disclosing party wishes to
     keep such information proprietary under this Agreement.

<PAGE>

                                  EXHIBIT J

VI.  Nothing in this Agreement shall be construed to grant to either party any
     right or license under any patent of the other party.

VII. The obligations under paragraphs I, II, III, and IV shall continue for a
     period of one (1) year after the end of term of a Lease Agreement Between
     Stratus 7000 West Joint Venture as Landlord and Silicon Laboratories Inc.
     as Tenant dated OCTOBER 27, 1999.

VIII. It is understood by both parties that such information may relate to
     products that are under development or planned for development. BOTH
     PARTIES UNDERSTAND THAT NO WARRANTIES ARE MADE OR IMPLIED REGARDING THE
     ACCURACY OF THIS INFORMATION. Neither party accepts responsibility for any
     expense, losses, or action incurred or undertaken by the other as a result
     of the receipt of this information. It is further understood by both
     parties that neither party warrants or represents that it will introduce
     any product to which the information is disclosed herein is related.

IX   The adjudication of this agreement shall be governed by the laws of the
     State of Texas.

X.   The existence of this agreement and, the fact that confidential information
     exists and has been disclosed constitutes confidential information and
     shall be treated as such under the terms of this agreement.

By    /s/ Navdeep S. Sooch                   By   /s/ William H. Armstrong, III
      -------------------------                   -----------------------------
      Signature                                   Signature

      -------------------------                   -----------------------------
      Navdeep S. Sooch                            William H. Armstrong, III

      -------------------------                   -----------------------
      Chairman and Chief Executive Officer        President and CEO
      Silicon Laboratories Inc.                   Stratus Properties Inc.,
                                                  a Delaware limited
                                                  liability company

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