Document:

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   [LOGO]
IMPERIAL BANK
 MEMBER FDIC
<TABLE>
<CAPTION>
                                PROMISSORY NOTE
<S>            <C>         <C>         <C>        <C>   <C>         <C>      <C>      <C>
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  PRINCIPAL    LOAN DATE    MATURITY    LOAN NO   CALL  COLLATERAL  ACCOUNT  OFFICER  INITIALS
$2,000,000.00  12-16-1999  06-16-2003  721000049                    622074     619       CJ
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References in the shaded area are for Lender's use only and do not limit the applicability of
this document to any particular loan or item.
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BORROWER: SILICON LABORATORIES INC., A DELAWARE  LENDER: IMPERIAL BANK
          CORPORATION                                    EMERGING GROWTH INDUSTRIES GROUP -
          4635 BOSTON LANE                               SOUTHWEST REGIONAL OFFICE
          AUSTIN, TX 78735                               226 AIRPORT PARKWAY
                                                         SAN JOSE, CA 95110-1024
==============================================================================================
  PRINCIPAL AMOUNT: $2,000,000.00     INITIAL RATE: 8.500%     DATE OF NOTE: DECEMBER 16, 1999
</TABLE>

PROMISE TO PAY. SILICON LABORATORIES INC., A DELAWARE CORPORATION
("BORROWER") PROMISES TO PAY TO IMPERIAL BANK ("LENDER"), OR ORDER, IN LAWFUL
MONEY OF THE UNITED STATES OF AMERICA, THE PRINCIPAL AMOUNT OF TWO MILLION &
00/100 DOLLARS ($2,000,000.00) OR SO MUCH AS MAY BE OUTSTANDING, TOGETHER
WITH INTEREST ON THE UNPAID OUTSTANDING PRINCIPAL BALANCE OF EACH ADVANCE.
INTEREST SHALL BE CALCULATED FROM THE DATE OF EACH ADVANCE UNTIL REPAYMENT OF
EACH ADVANCE.

PAYMENT. BORROWER WILL PAY THIS LOAN IN ACCORDANCE WITH THE FOLLOWING PAYMENT
SCHEDULE:

        ADVANCES UNDER THE NOTE SHALL BE AVAILABLE THROUGH JUNE 16, 2000
        ("NON-REVOLVING DRAW PERIOD"). DURING THE NON-REVOLVING DRAW PERIOD,
        INTEREST ONLY SHALL BE DUE MONTHLY BEGINNING JANUARY 16, 2000. ON
        JUNE 16, 2000, THE OUTSTANDING PRINCIPAL BALANCE OF THE ADVANCES UNDER
        THE NOTE SHALL BE PAYABLE MONTHLY IN 36 EQUAL PAYMENTS OF PRINCIPAL
        PLUS ACCRUED INTEREST BEGINNING JULY 16, 2000. ALL PRINCIPAL AND
        ACCRUED BUT UNPAID INTEREST SHALL IN ANY EVENT BE DUE AND PAYABLE ON
        OR BEFORE JUNE 16, 2003.

The annual interest rate for this Note is computed on a 365/360 basis; that
is, by applying the ratio of the annual interest rate over a year of 360
days, multiplied by the outstanding principal balance, multiplied by the
actual number of days the principal balance is outstanding. Borrower will pay
Lender at Lender's address shown above or at such other place as Lender may
designate in writing. Unless otherwise agreed or required by applicable law,
payments will be applied first to any unpaid collection costs and any late
charges, then to any unpaid interest, and any remaining amount to principal.

VARIABLE INTEREST RATE. The interest rate on this Note is subject to change
from time to time based on changes in an index which is the Imperial Bank
Prime Rate (the "Index"). The Prime Rate is the rate announced by Lender as
its Prime Rate of interest from time to time. Lender will tell Borrower the
current Index rate upon Borrower's request. Borrower understands that Lender
may make loans based on other rates as well. The interest rate change will
not occur more often than each day. THE INDEX CURRENTLY IS 8.500%. THE
INTEREST RATE TO BE APPLIED TO THE UNPAID PRINCIPAL BALANCE OF THIS NOTE WILL
BE AT A RATE EQUAL TO THE INDEX, RESULTING IN AN INITIAL RATE OF 8.500%.
NOTICE: Under no circumstances will the interest rate on this Note be more
than the maximum rate allowed by applicable law.

PREPAYMENT; MINIMUM INTEREST CHARGE. Borrower agrees that all loan fees and
other prepaid finance charges are earned fully as of the date of the loan and
will not be subject to refund upon early payment (whether voluntary or as a
result of default), except as otherwise required by law. In any event, even
upon full prepayment of this Note, Borrower understands that Lender is
entitled to a MINIMUM INTEREST CHARGE OF $250.00. Other than Borrower's
obligation to pay any minimum interest charge, Borrower may pay without
penalty all or a portion of the amount owed earlier than it is due. Early
payments will not, unless agreed to by Lender in writing, relieve Borrower of
Borrower's obligation to continue to make payments of accrued unpaid
interest. Rather, they will reduce the principal balance due.

LATE CHARGE. If a payment is 10 DAYS OR MORE LATE, Borrower will be charged
5.000% OF THE UNPAID PORTION OF THE REGULARLY SCHEDULED PAYMENT.

DEFAULT. Borrower will be in default if any of the following happens: (a)
"Borrower fails to make any payment when due which is not cured by Borrower
within ten (10) days of receipt of notice thereof". (b) Borrower breaks any
promise Borrower has made to Lender, or Borrower fails to comply with or to
perform when due any other term, obligation, covenant, or condition contained
in this Note or any agreement related to this Note, or in any other agreement
or loan Borrower has with Lender. (c) Any representation or statement made or
furnished to Lender by Borrower or on Borrower's behalf is false or
misleading in any meterial respect either now or at the time made or
furnished. (d) Borrower becomes insolvent, a receiver is appointed for any
part of Borrower's property, Borrower makes an assignment for the benefit of
creditors, or any proceeding is commenced either by Borrower or against
Borrower under any bankruptcy or insolvency laws. (e) Any creditor tries to
take any of Borrower's property on or in which Lender has a lien or security
interest. This includes a garnishment of any of Borrower's accounts with
Lender. (g) A material adverse change occurs in Borrower's financial
condition, or Lender believes the prospect of payment or performance of the
indebtedness is impaired.

If any default, other than a default in payment, is curable and if Borrower
has not been given a notice of a breach of the same provision of this Note
within the preceding twelve (12) months, it may be cured (and no event of
default will have occurred) if Borrower, after receiving written notice from
Lender demanding cure of such default: (a) cures the default within ten (10)
days; or (b) if the cure requires more than ten (10) days, immediately
initiates steps which Lender deems in Lender's sole discretion to be
sufficient to cure the default and thereafter continues and completes all
reasonable and necessary steps sufficient to produce compliance as soon as
reasonably practical.

LENDER'S RIGHTS. Upon default, Lender may declare the entire unpaid principal
balance on this Note and all accrued unpaid interest immediately due, without
notice, and then Borrower will pay that amount. Upon Borrower's failure to
pay all amounts declared due pursuant to this section, including failure to
pay upon final maturity, Lender, at its option, may also, if permitted under
applicable law, do one or both of the following: (a) increase the variable
interest rate on this Note to 5.000 percentage points over the Index, and (b)
add any unpaid accrued interest to principal and such sum will bear interest
therefrom until paid at the rate provided in this Note (including any
increased rate). Lender may hire or pay someone else to help collect this
Note if Borrower does not pay. Borrower also will pay Lender that amount.
This includes, subject to any limits under applicable law, Lender's
attorneys' fees and Lender's legal expenses whether or not there is a
lawsuit, including attorneys' fees and legal expenses for bankruptcy
proceedings (including efforts to modify or vacate any automatic stay or
injunction), appeals, and any anticipated post-judgment collection services.
Borrower also will pay any court costs, in addition to all other sums
provided by law. THIS NOTE HAS BEEN DELIVERED TO LENDER AND ACCEPTED BY
LENDER IN THE STATE OF CALIFORNIA. IF THERE IS A LAWSUIT, BORROWER AGREES UPON
LENDER'S REQUEST TO SUBMIT TO THE JURISDICTION OF THE COURTS OF LOS ANGELES
COUNTY, THE STATE OF CALIFORNIA. LENDER AND BORROWER HEREBY WAIVE THE RIGHT
TO ANY JURY TRIAL IN ANY ACTION, PROCEEDING, OR COUNTERCLAIM BROUGHT BY
EITHER LENDER OR BORROWER AGAINST THE OTHER. (INITIAL HERE  NSS  JMcG) THIS
NOTE SHALL BE GOVERNED BY AND CONSTRUED IN ACCORDANCE WITH THE LAWS OF THE
STATE OF CALIFORNIA.

DISHONORED ITEM FEE. Borrower will pay a fee to Lender of $25.00 if Borrower
makes a payment on Borrower's loan and the check or preauthorized charge with
which Borrower pays is later dishonored.

RIGHT OF SETOFF. Borrower grants to Lender a contractual security interest
in, and hereby assigns, conveys, delivers, pledges, and transfers to Lender
all Borrower's right, title and interest in and to, Borrower's accounts with
Lender (whether checking, savings, or some other account), including without
limitation all accounts held jointly with someone else and all accounts
Borrower may open in the future, excluding however all IRA and Keogh
accounts, and all trust accounts for which the grant of a security interest
would be prohibited by law. Borrower authorizes Lender, to the extent
permitted by applicable law, to charge or setoff all sums owing on this Note
against any and all such accounts.

LINE OF CREDIT. This Note evidences a straight line of credit. Once the total
amount of principal has been advanced, Borrower is not entitled to further
loan advances. Advances under this Note may be requested orally by Borrower
or by an authorized person. All oral requests shall be confirmed in writing
on the day of the request. All communications, instructions, or directions
by telephone or otherwise to Lender are to be directed to Lender's office
shown above. The following party or parties are authorized to request
advances under the line of credit until Lender receives from Borrower at
Lender's address shown above written notice of revocation of their authority:
JOHN MCGOVERN, CFO/SECRETARY; AND NAVDEEP S. SOOCH, CHAIRMAN/CEO. Borrower
agrees to be liable for all sums either: (a) advanced in accordance with the
instructions of an authorized person or (b) credited to any of Borrower's
accounts with Lender. The unpaid principal balance owing on this Note at any
time may be evidenced by endorsements on this Note or by Lender's internal
records, including daily computer print-outs. Lender will have no obligation
to advance funds under this Note if: (a) Borrower is in default under the
terms of this Note or any agreement that Borrower has with Lender, including
any agreement made in connection with the signing of this Note; (b) Borrower
ceases doing business or is insolvent; (c) (d) Borrower has applied funds
provided pursuant to this Note for purposes other than those authorized by
Lender; or (e)
<PAGE>

12-16-1999                      PROMISSORY NOTE                           Page 2
                                  (CONTINUED)
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                                                    JMcG     NSS     CJ
                                                    -----   -----   ----

REFERENCE PROVISION.  1. Other than (i) non-judicial foreclosure and all
matters in connection therewith regarding security interests in real or
personal property; or (ii) the appointment of a receiver, or the exercise of
other provisional remedies (any and all of which may be initiated pursuant to
applicable law), each controversy, dispute or claim between the parties
arising out of or relating to this document ("Agreement"), which controversy,
dispute or claim is not settled in writing within thirty (30) days after the
"Claim Date" (defined as the date on which a party subject to the Agreement
gives written notice to all other parties that a controversy, dispute or
claim exists), will be settled by a reference proceeding in California in
accordance with the provisions of Section 638 et seq. of the California Code
of Civil Procedure, or their successor section ("CCP"), which shall
constitute the exclusive remedy for the settlement of any controversy,
dispute or claim concerning this Agreement, including whether such
controversy, dispute or claim is subject to the reference proceeding and
except as set forth above, the parties waive their rights to initiate any
legal proceedings against each other in any court or jurisdiction other than
the Superior Court in the County where the Real Property, if any, is located
or Los Angeles County if none (the "Court"). The referee shall be a retired
Judge of the Court selected by mutual agreement of the parties, and if they
cannot so agree within forty-five (45) days after the Claim Date, the referee
shall be promptly selected by the Presiding Judge of the Court (or his
representative). The referee shall be appointed to sit as a temporary judge,
with all of the powers for a temporary judge, as authorized by law, and upon
selection should take and subscribe to the oath of office as provided for in
Rule 244 of the California Rules of Court (or any subsequently enacted
Rule). Each party shall have one peremptory challenge pursuant to CCP 170.6
The referee shall (a) be requested to set the matter for hearing within sixty
(60) days after the Claim Date and (b) try any and all issues of law or fact
and report a statement of decision upon them, if possible, within ninety (90)
days of the Claim Date. Any decision rendered by the referee will be final,
binding and conclusive and judgment shall be entered pursuant to CCP 644 in
any court in the State of California having jurisdiction. Any party may apply
for a reference proceeding at any time after thirty (30) days following
notice to any other party of the nature of the controversy, dispute or claim,
by filing a petition for a hearing and/or trial. All discovery permitted by
this Agreement shall be completed no later than fifteen (15) days before the
first hearing date established by the referee. The referee may extend such
period in the event of a party's refusal to provide requested discovery for
any reason whatsoever, including, without limitation, legal objections raised
to such discovery or unavailability of a witness due to absence or illness.
No party shall be entitled to "priority" in conducting discovery. Depositions
may be taken by either party upon seven (7) days written notice, and request
for production or inspection of documents shall be responded to within ten
(10) days after service. All disputes relating to discovery which cannot be
resolved by the parties shall be submitted to the referee whose decision
shall be final and binding upon the parties. Pending appointment of the
referee as provided herein, the Superior Court is empowered to issue
temporary and/or provisional remedies, as appropriate.

2. Except as expressly set forth in this Agreement, the referee shall
determine the manner in which the reference proceeding is conducted including
the time and place of all hearings, the order of presentation of evidence,
and all other questions that arise with respect to the course of the
reference proceeding. All proceedings and hearings conducted before the
referee, except for trial, shall be conducted without a court reporter,
except that when any party so requests, a court reporter will be used at any
hearing conducted before the referee. The party making such a request shall
have the obligation to arrange for and pay for the court reporter. The costs
of the court reporter at the trial shall be borne equally by the parties.

3. The referee shall be required to determine all issues in accordance with
existing case law and the statutory laws of the State of California. The rules
of evidence applicable to proceedings at law in the State of California will
be applicable to the reference proceeding. The referee shall be empowered to
enter equitable as well as legal relief, to provide all temporary and/or
provisional remedies and to enter equitable orders that will be binding upon
the parties. The referee shall issue a single judgment at the close of the
reference proceeding which shall dispose of all of the claims of the parties
that are the subject of the reference. The parties hereto expressly reserve
the right to contest or appeal from the final judgment or any appealable
order or appealable judgment entered by the referee. The parties hereto
expressly reserve the right to findings of fact, conclusions of law, a
written statement of decision, and the right to move for a new trial or a
different judgment, which new trial, if granted, is also to be a reference
proceeding under this provision.

4. In the event that the enabling legislation which provides for appointment
of a referee is repealed (and no successor statute is enacted), any dispute
between the parties that would otherwise be determined by the reference
procedure herein described will be resolved and determined by arbitration.
The arbitration will be conducted by a retired judge of the Court, in
accordance with the California Arbitration Act, 1280 through 1294.2 of the
CCP as amended from time to time. The limitations with respect to discovery
as set forth hereinabove shall apply to any such arbitration proceeding.

CREDIT TERMS AND CONDITIONS AGREEMENT. This Note is subject to the provisions
of the Credit Terms and Conditions Agreement dated March 28, 1997 and all
amendments thereto and replacements therefor.

GENERAL PROVISIONS. Lender may delay or forgo enforcing any of its rights or
remedies under this Note without losing them. Borrower and any other person
who signs, or endorses this Note, to the extent allowed by law, waive any
applicable statute of limitations, presentment, demand for payment, protest
and notice of dishonor. Upon any change in the terms of this Note, and unless
otherwise expressly stated in writing, no party who signs this Note, whether
as maker, accommodation maker or endorser, shall be released from liability.
All such parties agree that Lender may renew or extend (repeatedly and for
any length of time) this loan, or release any party or guarantor or
collateral; or impair, fail to realize upon or perfect Lender's security
interest in the collateral; and take any other action deemed necessary by
Lender without the consent of or notice to anyone. All such parties also
agree that Lender may modify this loan without the consent of or notice to
anyone other than the party with whom the modification is made.

PRIOR TO SIGNING THIS NOTE, BORROWER READ AND UNDERSTOOD ALL THE PROVISIONS
OF THIS NOTE, INCLUDING THE VARIABLE INTEREST RATE PROVISIONS. BORROWER
AGREES TO THE TERMS OF THE NOTE AND ACKNOWLEDGES RECEIPT OF A COMPLETED COPY
OF THE NOTE.

BORROWER:

SILICON LABORATORIES INC., A DELAWARE CORPORATION

BY: /s/ John W. McGovern                 BY: /s/ Navdeep S. Sooch
   -------------------------------          -------------------------------
   JOHN MCGOVERN, CFO/SECRETARY             NAVDEEP S. SOOCH, CHAIRMAN/CEO

===============================================================================<PAGE>

NEITHER THIS WARRANT NOR ANY OF THE SECURITIES ISSUABLE UPON EXERCISE HEREOF
HAVE BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933, AS AMENDED (THE
"SECURITIES ACT"), OR ANY STATE SECURITIES LAW. NO TRANSFER OF THIS WARRANT OR
OF THE SECURITIES ISSUABLE UPON EXERCISE HEREOF SHALL BE VALID OR EFFECTIVE
UNLESS (A) SUCH TRANSFER IS MADE PURSUANT TO AN EFFECTIVE REGISTRATION STATEMENT
UNDER THE SECURITIES ACT AND IN COMPLIANCE WITH ANY APPLICABLE STATE SECURITIES
LAW, OR (B) THE HOLDER SHALL DELIVER TO THE COMPANY AN OPINION OF COUNSEL IN
FORM AND SUBSTANCE REASONABLY ACCEPTABLE TO THE COMPANY THAT SUCH TRANSFER IS
EXEMPT FROM THE REGISTRATION REQUIREMENTS OF THE SECURITIES ACT AND OF ANY
APPLICABLE STATE SECURITIES LAW.

Warrant No. A-001                                             November 20, 1997

                            SILICON LABORATORIES INC.

                        PREFERRED STOCK PURCHASE WARRANT

         Silicon Laboratories Inc., a Delaware corporation (the "COMPANY"),
hereby grants to Imperial Bancorp ("PURCHASER"), or its registered assigns or
transferees (Purchaser and each such assign or transferee being referred to
herein as a "HOLDER" and collectively as the "HOLDERS") the right to purchase,
at any time and from time to time on and after the date hereof until November
20, 2002 (the "EXPIRATION DATE"), up to 45,818 fully paid and nonassessable
shares of Series A Convertible Preferred Stock of the Company, par value $0.0001
per share (the "SERIES A PREFERRED STOCK"), on the terms and subject to the
conditions set forth below.

         1.       EXERCISE AND VESTING OF WARRANT.

                  1.1. EXERCISE PRICE. Subject to adjustment as hereinafter
provided, the rights represented by this Preferred Stock Purchase Warrant (this
"WARRANT") are exercisable on and after November 20, 1997 (the "EXERCISE DATE")
until the Expiration Date, at a price (the "EXERCISE PRICE") of $0.982144225 per
share of the Series A Preferred Stock issuable hereunder (hereinafter, the
"WARRANT SHARES"). The Exercise Price shall be payable in cash, or by certified
or official bank check. This Warrant shall be fully vested upon the initial
advance to the Company by Purchaser of funds pursuant to that certain Note
issued by the Company in favor of Purchaser dated November __, 1997 in the
maximum principal amount of $1,500,000.00.

                  1.2. METHOD OF EXERCISE. Upon surrender of this Warrant with a
duly executed Notice of Exercise in the form of ANNEX A attached hereto,
together with payment of the

<PAGE>

Exercise Price for the Warrant Shares purchased (except to the extent of
conversion pursuant to Section 1.3 herein), at the Company's principal executive
offices (presently located at 2024 East St. Elmo Road, Austin, Texas 78744-1018)
or at such other address as the Company shall have advised the Holder in writing
(the "DESIGNATED OFFICE"), the Holder shall be entitled to receive a certificate
or certificates for the Warrant Shares so purchased. The Company agrees that the
Warrant Shares shall be deemed to have been issued to the Holder as of the close
of business on the date on which this Warrant shall have been surrendered
together with the Notice of Exercise and payment for such Warrant Shares.

                  1.3. CONVERSION RIGHT.  In lieu of exercising this Warrant as
specified in Section 1.2, Holder may from time to time convert this Warrant, in
whole or in part, into a number of Warrant Shares determined by dividing (a) the
aggregate fair market value of the Warrant Shares or other securities otherwise
issuable upon exercise of this Warrant minus the aggregate Exercise Price of
such Warrant Shares by (b) the fair market value of one Warrant Share. The fair
market value of the Warrant Shares shall be determined pursuant to Section 1.4.

                  1.4. If the Warrant Shares are traded regularly in a public
market, the fair market value of the Warrant Shares shall be the closing price
of the Warrant Shares (or the closing price of the Company's stock into which
the Warrant Shares are convertible) reported for the business day immediately
before Holder delivers its Notice of Exercise to the Company. If the Warrant
Shares are not regularly traded in a public market, the Board of Directors of
the Company shall determine fair market value in its reasonable good faith
judgment. The foregoing notwithstanding, if Holder advises the Board of
Directors of the Company in writing that Holder disagrees with such
determination, then the Company and Holder shall promptly agree upon a reputable
investment banking firm to undertake such valuation. If the valuation of such
investment banking firm is greater than that determined by the Board of
Directors of the Company, then all fees and expenses of such investment banking
firm shall be paid by the Company. In all other circumstances, such fees and
expenses shall be paid by Holder.

         2.       TRANSFER; ISSUANCE OF STOCK CERTIFICATES; RESTRICTIVE LEGENDS.

                  2.1. TRANSFER. Subject to compliance with the restrictions on
transfer set forth in this Section 2, each transfer of this Warrant and all
rights hereunder, in whole or in part, shall be registered on the books of the
Company to be maintained for such purpose, upon surrender of this Warrant at the
Designated Office, together with a written assignment of this Warrant in the
form of ANNEX B attached hereto duly executed by the Holder or its agent or
attorney. Upon such surrender and delivery, the Company shall execute and
deliver a new Warrant or Warrants in the name of the assignee or assignees and
in the denominations specified in such instrument of assignment, and shall issue
to the assignor a new Warrant evidencing the portion of this Warrant not so
assigned, if any. A Warrant, if properly assigned in compliance with the
provisions hereof, may be exercised by the new Holder for the purchase of
Warrant Shares without having a new Warrant issued. Prior to due presentment for
registration of transfer thereof, the Company may deem and treat the registered
Holder of this Warrant as the

                                       2
<PAGE>

absolute owner hereof (notwithstanding any notations of ownership or writing
thereon made by anyone other than a duly authorized officer of the Company) for
all purposes and shall not be affected by any notice to the contrary. All
Warrants issued upon any assignment of Warrants shall be the valid obligations
of the Company, evidencing the same rights, and entitled to the same benefits as
the Warrants surrendered upon such registration of transfer or exchange.

                  2.2. STOCK CERTIFICATES. Certificates for the Warrant Shares
shall be delivered to the Holder within a reasonable time after the rights
represented by this Warrant shall have been exercised pursuant to Section 1, and
a new Warrant representing the shares of Series A Preferred Stock, if any, with
respect to which this Warrant shall not then have been exercised shall also be
issued to the Holder within such time. The issuance of certificates for Warrant
Shares upon the exercise of this Warrant shall be made without charge to the
Holder hereof including, without limitation, any documentary, stamp or similar
tax that may be payable in respect thereof, PROVIDED, HOWEVER, that the Company
shall not be required to pay any income tax to which the Holder hereof may be
subject in connection with the issuance of this Warrant or the Warrant Shares;
AND PROVIDED FURTHER, that if Warrant Shares are to be delivered in a name other
than the name of the Holder hereof representing any Warrant being exercised,
then no such delivery shall be made unless the person requiring the same has
paid to the Company the amount of transfer taxes or charges incident thereto, if
any.

                  2.3. RESTRICTIVE LEGENDS. (a) Except as otherwise provided in
this Section 2, each certificate for Warrant Shares initially issued upon the
exercise of this Warrant, and each certificate for Warrant Shares issued to any
subsequent transferee of any such certificate, shall be stamped or otherwise
imprinted with a legend in substantially the following form:

         THE SECURITIES REPRESENTED BY THIS CERTIFICATE HAVE NOT BEEN REGISTERED
UNDER THE SECURITIES ACT OF 1933, AS AMENDED, AND MAY NOT BE OFFERED, SOLD OR
OTHERWISE TRANSFERRED, PLEDGED OR HYPOTHECATED UNLESS AND UNTIL SUCH SECURITIES
ARE REGISTERED UNDER SUCH ACT OR AN OPINION OF COUNSEL SATISFACTORY TO THE
COMPANY IS OBTAINED TO THE EFFECT THAT SUCH REGISTRATION IS NOT REQUIRED.

                  (b) Except as otherwise provided in this Section 2, each
Warrant shall be stamped or other-wise imprinted with a legend in substantially
the following form:

         NEITHER THIS WARRANT NOR ANY OF THE SECURITIES ISSUABLE UPON EXERCISE
THEREOF HAVE BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933, AS AMENDED (THE
"SECURITIES ACT"), OR ANY STATE SECURITIES LAW, NO TRANSFER OF THIS WARRANT OR
OF THE SECURITIES ISSUABLE UPON EXERCISE HEREOF SHALL BE VALID OR EFFECTIVE
UNLESS (A) SUCH TRANSFER IS MADE PURSUANT TO AN EFFECTIVE REGISTRATION STATEMENT
UNDER THE SECURITIES ACT AND IN COMPLIANCE WITH ANY APPLICABLE STATE SECURITIES
LAW, OR (B) THE HOLDER SHALL DELIVER TO THE COMPANY AN OPINION OF

                                       3
<PAGE>

COUNSEL IN FORM AND SUBSTANCE REASONABLY ACCEPTABLE TO THE COMPANY THAT SUCH
TRANSFER IS EXEMPT FROM THE REGISTRATION REQUIREMENTS OF THE SECURITIES ACT AND
OF ANY APPLICABLE STATE SECURITIES LAW.

Notwithstanding the foregoing, the legend requirements of this Section 2.3 shall
terminate as to any particular Warrant or Warrant Share when the Company shall
have received from the Holder thereof an opinion of counsel in form and
substance reasonably acceptable to the Company that such legend is not required
in order to ensure compliance with the Securities Act. Whenever the restrictions
imposed by this Section 2.3 shall terminate, the Holder hereof or of Warrant
Shares, as the case may be, shall be entitled to receive from the Company
without cost to such Holder a new Warrant or certificate for Warrant Shares of
like tenor, as the case may be, without such restrictive legend.

         3.       ADJUSTMENT OF NUMBER OF SHARES; EXERCISE PRICE; NATURE OF
                  SECURITIES ISSUABLE UPON EXERCISE OF WARRANTS.

                  3.1. EXERCISE PRICE; ADJUSTMENT OF NUMBER OF SHARES. The
Exercise Price set forth in Section 1 hereof and the number of shares
purchasable hereunder shall be subject to adjustment from time to time as
hereinafter provided.

                  3.2. CONVERSION OF SERIES A SHARES. If all of the Company's
Series A Preferred Stock shall be, or if outstanding would be, at any time prior
to the Expiration Date, converted into shares of the Company's Common Stock,
then the unexercised portion of this Warrant shall immediately become
exercisable for that number of shares of the Company's Common Stock equal to the
number of shares of the Common Stock that would have been received if this
Warrant had been exercised in full and the Series A Preferred Stock received
thereupon had been simultaneously converted immediately prior to such event, and
the Exercise Price shall be immediately adjusted to equal the quotient obtained
by dividing (x) the aggregate Exercise Price of the maximum number of shares of
Series A Preferred Stock for which this Warrant was exercisable immediately
prior to such conversion, by (y) the number of shares of Common Stock for which
this Warrant is exercisable immediately after such conversion; provided,
however, that in no event shall the Exercise Price as so adjusted be less than
the par value of the Common Stock.

                  3.3.   MERGER, SALE OF ASSETS, ETC.  If at any time while this
Warrant, or any portion thereof, is outstanding and unexpired there shall be a
reorganization (other than a combination, reclassification, exchange, or
subdivision of shares as provided in Sections 3.4 and 3.5), merger or
consolidation of the Company with or into another corporation in which the
Company is not the surviving entity, or a merger in which the Company is the
surviving entity but the shares of the Company's capital stock outstanding
immediately prior to the merger are converted by virtue of the merger into other
property, whether in the form of securities, cash or otherwise, or a sale or
transfer of the Company's properties and assets as, or substantially

                                       4
<PAGE>

as, an entirety to any other person, then, as a part of such reorganization,
merger, consolidation, sale or transfer, lawful provision shall be made so that
the Holder of this Warrant shall thereafter be entitled to receive upon exercise
of this Warrant, during the period specified herein and upon payment of the
Exercise Price then in effect, the number of shares of stock or other securities
or cash or property of the successor corporation resulting from such
reorganization, merger, consolidation, sale or transfer that a Holder of the
shares deliverable upon exercise of this Warrant would have been entitled to
receive in such reorganization, consolidation, merger, sale or transfer if this
Warrant had been exercised immediately before such reorganization,
consolidation, merger, sale or transfer, all subject to further adjustment as
provided in this Section 3. The foregoing provisions of this Section 3.3 shall
similarly apply to successive reorganizations, consolidations, mergers, sales
and transfers and to the stock and securities of any other corporation that are
at the time receivable upon the exercise of this Warrant. If the per-share
consideration payable to the Holder hereof for shares in connection with any
such transaction is in a form other than cash or securities, then the value of
such consideration shall be determined in good faith by the Company's Board of
Directors. In all events, appropriate adjustment shall be made in the
application of the provisions of this Warrant with respect to the rights and
interests of the Holder hereof after the transaction, to the end that the
provisions of this Warrant shall be applicable after that event, as near as
reasonably may be, in relation to any shares or other property deliverable after
that event upon exercise of this Warrant.

                  3.4. RECLASSIFICATION, ETC. If the Company, at any time while
this Warrant, or any portion thereof, remains outstanding and unexpired, shall,
by the reclassification or exchange of securities or otherwise, change any of
the securities as to which purchase rights under this Warrant exist into the
same or a different number of securities of any other class or classes, this
Warrant shall thereafter represent the right to acquire such number and kind of
securities as would have been issuable as the result of such change with respect
to the securities that were subject to the purchase rights under this Warrant
immediately prior to such reclassification, exchange or other change and the
Exercise Price therefor shall be appropriately adjusted, all subject to further
adjustment as provided in this Section 3. No adjustment shall be made pursuant
to this Section 3.4, upon any conversion of the Series A Preferred Stock which
is the subject of Section 3.2.

                  3.5. STOCK SPLITS, STOCK DIVIDENDS AND REVERSE STOCK SPLITS.
In case at any time the Company shall split or subdivide the outstanding shares
of Series A Preferred Stock into a greater number of shares, or shall declare
and pay any stock dividend with respect to its outstanding stock that has the
effect of increasing the number of outstanding shares of Series A Preferred
Stock, the Exercise Price in effect immediately prior to such subdivision or
stock dividend shall be proportionately reduced (but not below the par value of
the Series A Preferred Stock) and the number of Warrant Shares purchasable
pursuant to this Warrant immediately prior to such subdivision or stock dividend
shall be proportionately increased, and conversely, in case at any time the
Company shall combine its outstanding shares of Series A Preferred Stock into a
smaller number of shares, the Exercise Price in effect immediately prior to such
combination

                                       5
<PAGE>

shall be proportionately increased and the number of Warrant Shares purchasable
upon the exercise of this Warrant immediately prior to such combination shall be
proportionately reduced.

         4.   REGISTRATION; EXCHANGE AND REPLACEMENT OF WARRANT; RESERVATION OF
              SHARES.

         The Company shall keep at the Designated Office a register in which the
Company shall provide for the registration, transfer and exchange of this
Warrant. The Company shall not at any time, except upon the dissolution,
liquidation or winding-up of the Company, close such register so as to result in
preventing or delaying the exercise or transfer of this Warrant.

         The Company may deem and treat the person in whose name this Warrant is
registered as the Holder and owner hereof for all purposes and shall not be
affected by any notice to the contrary, until presentation of this Warrant for
registration or transfer as provided in this Section 4.

         Upon receipt by the Company of evidence reasonably satisfactory to it
of the loss, theft, destruction or mutilation of this Warrant and (in case of
loss, theft or destruction) of indemnity satisfactory to it, and (in the case of
mutilation) upon surrender and cancellation of this Warrant, the Company will
(in the absence of notice to the Company that the Warrant has been acquired by a
BONA FIDE purchaser) make and deliver a new Warrant of like tenor, in lieu of
this Warrant without requiring the posting of any bond or the giving of any
security.

         The Company shall at all times reserve and keep available out of its
authorized shares of Series A Preferred Stock, solely for the purpose of
issuance upon the exercise of this Warrant, such number of shares of Series A
Preferred Stock as shall be issuable upon the exercise hereof. The Company
covenants and agrees that, upon exercise of this Warrant and payment of the
Exercise Price therefor, all Warrant Shares issuable upon such exercise shall be
duly and validly issued, fully paid and non-assessable.

         5.   FRACTIONAL WARRANTS AND FRACTIONAL SHARES.

         If the number of Warrant Shares purchasable upon the exercise of this
Warrant is adjusted pursuant to Section 3 hereof, the Company shall nevertheless
not be required to issue fractions of shares, upon exercise of this Warrant or
otherwise, or to distribute certificates that evidence fractional shares. With
respect to any fraction of a share called for upon any exercise hereof, the
Company shall pay to the Holder an amount in cash equal to such fraction
multiplied by the current market value of such fractional share as may be
prescribed by the Board of Directors of the Company.

                                       6
<PAGE>

         6.    WARRANT HOLDERS NOT DEEMED STOCKHOLDERS.

         No Holder of this Warrant shall, as such, be entitled to vote or to
receive dividends or be deemed the Holder of Warrant Shares that may at any time
be issuable upon exercise of this Warrant for any purpose whatsoever, nor shall
anything contained herein be construed to confer upon the Holder of this
Warrant, as such, any of the rights of a stockholder of the Company or any right
to vote for the election of directors or upon any matter submitted to
stockholders at any meeting thereof, or for the election of directors or upon
any matter submitted to stockholders at any meeting thereof, or to give or
withhold consent to any corporate action (whether upon any recapitalization,
issue or reclassification of stock, change of par value or change of stock to no
par value, consolidation, merger or conveyance or otherwise), or to receive
notice of meetings, or to receive dividends or subscription rights, until such
Holder shall have exercised this Warrant and been issued Warrant Shares in
accordance with the provisions hereof.

         7.    NOTICES.

         All notices, requests, consents and other communications hereunder
shall be in writing and shall be deemed to have been duly made when delivered
personally, or mailed by registered or certified mail, return receipt requested,
or telecopied or telexed and confirmed in writing and delivered personally or
mailed by registered or certified mail, return receipt requested (a) if to the
Holder of this Warrant, to the address of such Holder as shown on the books of
the Company, or (b) if to the Company, to the address set forth in Section 1.2
of this Warrant; or at such other address as the Holder or the Company may
hereafter have advised the other.

         8.    SUCCESSORS.

         All the covenants, agreements, representations and warranties contained
in this Warrant shall bind the parties hereto and their respective heirs,
executors, administrators, distributees, successors, assigns and transferees.

         9.    LAW GOVERNING.

         This Warrant shall be construed and enforced in accordance with, and
governed by, the laws of the State of Texas (not including the choice of law
rules thereof) regardless of the jurisdiction of creation or domicile of the
Company or its successors or of the Holder at any time hereof.

                                       7
<PAGE>

         10.   ENTIRE AGREEMENT: AMENDMENTS AND WAIVERS.

         This Warrant sets forth the entire understanding of the parties with
respect to the transactions contemplated hereby. The failure of any party to
seek redress for the violation or to insist upon the strict performance of any
term of this Warrant shall not constitute a waiver of such term and such party
shall be entitled to enforce such term without regard to such forbearance. This
Warrant may be amended, and any breach of or compliance with any covenant,
agreement, warranty or representation may be waived, only if the Company has
obtained the written consent or written waiver of the Holder, and then such
consent or waiver shall be effective only in the specific instance and for the
specific purpose for which given.

         11.   SEVERABILITY; HEADINGS.

         If any term of this Warrant as applied to any person or to any
circumstance is prohibited, void, invalid or unenforceable in any jurisdiction,
such term shall, as to such jurisdiction, be ineffective to the extent of such
prohibition or invalidity without in any way affecting any other term of this
Warrant or affecting the validity or enforceability of this Warrant or of such
provision in any other jurisdiction. The Section headings in this Warrant have
been inserted for purposes of convenience only and shall have no substantive
effect.

            [The balance of this page intentionally left blank]

                                       8
<PAGE>

         IN WITNESS WHEREOF, the Company has caused this Warrant to be duly
executed as of the date first written above.

                                    SILICON LABORATORIES INC.

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

                                    By:  /s/  John W. McGovern
                                       ----------------------------------
                                         John W. McGovern
                                         Chief Financial Officer

Accepted and agreed:

IMPERIAL BANCORP

By:  /s/ Stephen Obermeyer
   ---------------------------
     Name:  STEPHEN OBERMEYER
     Title: VICE PRESIDENT

                                       9
<PAGE>

                                     ANNEX A

                               NOTICE OF EXERCISE

                      (TO BE EXECUTED UPON PARTIAL OR FULL
                         EXERCISE OF THE WITHIN WARRANT)

         1.  The undersigned hereby elects to purchase _______ shares of
Series A Convertible Preferred Stock of Silicon Laboratories Inc. pursuant to
the terms of the attached Warrant, and tenders herewith payment of the purchase
price of such shares in full.

         1. The undersigned hereby elects to convert the attached Warrant into
Warrant Shares in the manner specified in the Warrant. This conversion is
exercised with respect to _____________________ of the Warrant Shares covered by
the Warrant.

          [STRIKE THE PARAGRAPH NUMBERED 1 ABOVE THAT DOES NOT APPLY.]

         2.  Please issue a certificate or certificates representing said shares
in the name of the undersigned or in such other name as is specified below:

         Ms. Christine M. McCarthy
         Chief Financial Officer
         Controllers Department
         Imperial Bank
         P.O. Box 92991
         Los Angeles, CA 90009

         3.  The undersigned represents it is acquiring the shares solely for
its own account and not as a nominee for any other party and not with a view
toward the resale or distribution thereof except in compliance with applicable
securities laws.

                                       IMPERIAL BANCORP

                                       ----------------------------------
                                       (Signature)

                                       ----------------------------------
                                       (Date)

                                      A-1
<PAGE>

                                    ANNEX B

                                 ASSIGNMENT FORM

         FOR VALUE RECEIVED the undersigned registered owner of this Warrant
hereby sells, assigns and transfers unto the Assignee named below all of the
rights of the undersigned under this Warrant, with respect to the number of
shares of Series A Convertible Preferred Stock set forth below:

--------------------------------------------------------------------------------
                                          No. of Shares of
Name and Address of Assignee              Series A Convertible Preferred Stock
----------------------------              ------------------------------------
--------------------------------------------------------------------------------

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

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

and does hereby irrevocably constitute and appoint _________________________
attorney-in-fact to register such transfer onto the books of Silicon
Laboratories Inc. maintained for the purpose, with full power of substitution in
the premises.

Dated: _________________               Print Name:____________________

                                       Signature:_____________________

                                       Witness:_______________________

NOTICE:     The signature on this assignment must correspond with the name as
            written upon the face of this Warrant in every particular, without
            alteration or enlargement or any change whatsoever.

                                      B-1

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