<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. B-001                                              September 4, 1998

                           SILICON LABORATORIES INC.

                       PREFERRED STOCK PURCHASE WARRANT

         Silicon Laboratories Inc., a Delaware corporation (the "COMPANY"),
hereby grants to Imperial Bank ("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 the fifth
(5th) anniversary of the date hereof (the "EXPIRATION DATE"), up to 4,765 fully
paid and nonassessable shares of Series B Convertible Preferred Stock of the
Company, par value $0.0001 per share (the "SERIES B 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 the date hereof (the "EXERCISE DATE")
until the Expiration Date, at a price (the "EXERCISE PRICE") of $4.76 per share
of the Series B Preferred Stock issuable hereunder (hereinafter, the "WARRANT
SHARES"). The Exercise Price shall be payable in cash, or by certified or
official bank check.

                  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 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

<PAGE>

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. VALUATION. 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
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

                                       2

<PAGE>

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 B 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 otherwise 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 COUNSEL IN
FORM AND SUBSTANCE REASONABLY ACCEPTABLE TO THE COMPANY THAT SUCH TRANSFER IS
EXEMPT FROM THE REGISTRATION


                                       3

<PAGE>

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 B SHARES. If all of the Company's
Series B 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 be converted into the right
to purchase 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 B 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 B 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 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


                                       4

<PAGE>

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 B 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 B 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 B 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 B 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 B Preferred Stock into a
smaller number of shares, the Exercise Price in effect immediately prior to such
combination 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.


                                       5

<PAGE>

         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 B Preferred Stock, solely for the purpose of
issuance upon the exercise of this Warrant, such number of shares of Series B
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.       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


                                       6

<PAGE>

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.

         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.


                                       7

<PAGE>

         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]

<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 BANK


By: /s/ Tommy Deavenport
    ----------------------------
    Name:  Tommy Deavenport
    Title: Senior 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 B 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 and deliver such certificate(s) to:

         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 BANK


                                            ------------------------------
                                                      (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 B Convertible Preferred Stock set forth below:

<TABLE>
<CAPTION>

--------------------------------------------------------------------------------
                                            No. of Shares of
Name and Address of Assignee                Series B Convertible Preferred Stock
--------------------------------------------------------------------------------
<S>                                         <C>

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

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

</TABLE>

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

<PAGE>

                                   EXHIBIT B

  Form of Amendment No.1 to Amended and Restated Investors' Rights Agreement


                                  (Attached)


                                       6