<PAGE>


                                 LEASE AGREEMENT



                                     BETWEEN



                         STRATUS 7000 WEST JOINT VENTURE



                                  AS LANDLORD,



                                       AND



                            SILICON LABORATORIES INC.


                                   AS TENANT,



               COVERING APPROXIMATELY 34,548 RENTABLE SQUARE FEET
                    OF THE BUILDING KNOWN (OR TO BE KNOWN) AS




                       7000 WEST AT LANTANA, BUILDING TWO


                                   LOCATED AT



                         7000 WEST WILLIAM CANNON DRIVE



                               AUSTIN, TEXAS 78735

<PAGE>

                             BASIC LEASE INFORMATION

Lease Date:                June 29, 2000

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. 2-200 containing approximately 34,548
                           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 1.0886.

Building:                  7000 West at Lantana Building Two, which contains
                           66,628 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 as Building One
                           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)
                           October 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., January 31, 2007, 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.

Basic Rental:              (i) for months 1-24, $47,555.32 per month, which is
                           based on an annual Basic Rental of $16.518 per
                           rentable square foot; (ii) for months 25-48,
                           $51,873.82 per month, which is

                                       i
<PAGE>

                           based on an annual Basic Rental of $18.018 per
                           rentable square foot and (iii) for months 49- 76,
                           $56,192.32 per month, which is based on an annual
                           Basic Rental of $19.518 per rentable square foot.

Security Deposit:          $ 69,147.82 in cash.

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:       51.85%, which is the percentage obtained by dividing
                           (a) the 34,548 rentable square feet in the Premises
                           by (b) the 66,628 rentable square feet in the
                           Building.

Tenant's Estimated
Proportionate Share
of Basic Costs:            Costs of $7.50 per rentable square foot which is
                           equal to $21,592.50 per month.

Initial Liability
Insurance Amount:          $3,000,000.00

Maximum Construction
Allowance:                 $22.00 per rentable square foot

Building's
Proportionate Share:       The percentage obtained by dividing (a) the 66,628
                           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 50%.

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:    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
                                                 ------------------------------
                                                 William H. Armstrong, III
                                                 President and CEO


                        TENANT:    SILICON LABORATORIES INC.

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



                                        ii
<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)     Adjustments to Basic Costs......................................................................  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)     Restoration of Services; Abatement..............................................................  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 Rights.........................................................  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

                                       iii

<PAGE>

                                                                                                                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>














                                       iv

<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>



















                                       v

<PAGE>

                                      LEASE


      THIS LEASE AGREEMENT (this "LEASE") is entered into as of June 29, 2000,
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. 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, 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
                  adjusted as provided in Section 4.(e). If the Annual Cost
                  Statement reveals that Tenant paid more for Basic Costs than
                  Tenant's Proportionate Share of Basic Costs in the year for
                  which such statement was prepared, then Landlord shall credit
                  Tenant

                                       1

<PAGE>

                  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%).

                           (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.

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

                                       2

<PAGE>

                  janitorial service and Tenant's Proportionate share of
                  Basic Costs shall be equitably reduced to reflect the same;
                  (4) an elevator for ingress and egress to the floor on
                  which the Premises are located, in common with other
                  tenants; (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. 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
                  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

                                       3

<PAGE>

                  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 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,

                                       4

<PAGE>

                  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 reasonably satisfactory to Landlord after
                  considering Tenant's continuing obligations of payment and
                  performance: (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 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 an Event of 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 the Requisite Square Feet 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. As used herein, the term "Requisite
                  Square Feet" shall mean the remainder of (x) 35,000 square
                  feet MINUS (y) the square footage of all other space in the
                  Project subleased by Tenant (or its assigns) to another
                  occupant at the time of the request.

                           (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

                                       5

<PAGE>

                  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 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.

                                       6

<PAGE>

                           (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 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.

                                       7

<PAGE>

                           (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":

                           (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) days, 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

                                       8

<PAGE>

                  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 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



<PAGE>

                  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.

                           (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

                                       10

<PAGE>

                  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 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       -  Subordination, Non-disturbance
                                                  and Attornment 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

                                       11

<PAGE>

                  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.

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 on 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
March 31, 2001, 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 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 non-disturbance 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.

                                       12

<PAGE>

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.

      DATED as of the date first written above.

                        LANDLORD:

                        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, General Partner

                                   By STRATUS PROPERTIES INC., a Delaware
                                   corporation, 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






                                       13

<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

[The architectual graphical layout of LEVEL TWO, Suite 200 indicating
stairwells, elevators and corridors.]


                                      A-1-1

<PAGE>

                                   EXHIBIT A-2

                                     PROJECT

[A map of the LANTANA CORPORATE CENTER, Stratus Properties, Inc. setting
forth building designated as Phase I and Phase II. Also indicated is the
layout of parking spaces and landscaping.]


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


                                       C-1

<PAGE>

         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 July 14, 2000, 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.
Notwithstanding the foregoing, Tenant's failure to provide final working
drawings by July 14, 2000, in accordance with Paragraph 2 of this Exhibit D
shall automatically be deemed to be a Tenant Delay, and Landlord shall not be
required to give Tenant notice thereof. 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). 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

                                       D-1

<PAGE>

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 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). $22.00 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-three (133)
undesignated vehicular parking spaces (including visitor and handicap) and
eighteen (18) reserved covered parking spaces in the surface parking lot (the
"PARKING FACILITIES") associated with the Building during the Term, including
any extensions and renewals and subject to such terms, conditions and
regulations as are from time to time applicable to patrons of the Parking
Facilities. These parking rights will be at no charge during the initial term.

                                       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

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").

                             W I T N E S S E T H:

     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 Official 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.




                                      G-1

<PAGE>

     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 (30) 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' FEES. 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/ Shery R. Layne
                                    -------------------------------------------
                                 Name: Shery 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, GP, L.L.C., a Texas
                                          limited liability company, its
                                          General Partner


                                          By: /s/ Hal R. Hall
                                             -----------------------------------
                                          Name:
                                               ---------------------------------
                                          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      )
                    )
COUNTY OF TRAVIS    )

         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
                                       -----------------------------------------
      June 16, 2002                    (Printed Name of Notary Public)
------------------------


STATE OF TEXAS      )
                    )
COUNTY OF DALLAS    )

         The foregoing instrument was ACKNOWLEDGED before me this 2 day of
NOVEMBER, 1999, by Hal Hall, the Vice Pres. 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
                                       -----------------------------------------
Oct 6 2002                             (Printed Name of Notary Public)
------------------------


                                                                          Page 7
<PAGE>

STATE OF TEXAS     )
                   )
COUNTY OF TRAVIS   )

         This instrument was ACKNOWLEDGED before me on the 29th day of October,
1999, by NAVDEEP S. SOOCH, the Chairman & 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
                                       -----------------------------------------
        4/27/02                        Printed Name of Notary Public
------------------------

EXHIBIT LIST

Exhibit A - Legal Description


                                                                          Page 8