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                                                                    Exhibit 10.1

                 MASTER REVOLVING NOTE
[COMERICA LOGO]  Variable Rate-Maturity Date-Obligatory Advances
                 (Business and Commercial Loans Only)

<Table>
<Caption>
Amount         Note Date            Maturity Date        Tax Identification Number
<S>            <C>                  <C>                  <C>
$5,000,000     September 5, 2001    September 5, 2003
</Table>

On the Maturity Date, as stated above, for value received, the undersigned
promise(s) to pay to the order of Comerica Bank-Texas ("Bank"),at any office of
the Bank in the State of Texas, Five Million Dollars (U.S.) (or that portion of
it advanced by the Bank and not repaid as later provided) with interest until
maturity, whether by acceleration or otherwise, or until Default, as later
defined, at a per annum rate equal to the lesser of (a) the Maximum Rate, as
later defined, or (b) the Stated Rate, as later defined and after that at a rate
equal to the rate of interest otherwise prevailing under this Note plus three
percent (3%) per annum (but in no event in excess of the Maximum Rate.) If on
any day the Stated Rate shall exceed the Maximum Rate for that day, the rate of
interest applicable to this Note shall be fixed at the Maximum Rate on that day
and on each day thereafter until the total amount of interest accrued on the
unpaid principal balance of this Note equals the total amount of interest which
would have accrued if there had been no Maximum Rate. Interest rate changes will
be effective for interest computation purposes as and when the Maximum Rate or
the Stated Rate, as applicable, changes. Subject to the limitations hereinbelow
set forth, interest shall be calculated on the basis of a 360-day year for the
actual number of days the principal is outstanding. The "Stated Rate" shall mean
the Bank's "prime rate" which is the annual rate of interest so designated by
the Bank and which is changed by the Bank from time to time. Accrued interest on
this Note shall be payable on the first day of each calendar month commencing
October 1, 2001, until the Maturity Date (set forth above) when all amounts
outstanding under this Note shall be due and payable in full. If the frequency
of interest payments is not otherwise specified, accrued interest on this Note
shall be payable monthly on the first day of each month. If any payment of
principal or interest under this Note shall be payable on a day other than a day
on which the Bank is open for business, this payment shall be extended to the
next succeeding business day and interest shall be payable at the rate specified
in this Note during this extension. A late payment charge equal to a reasonable
amount not to exceed 5% of each late payment may be charged on any payment not
received by the Bank within 10 calendar days after the payment due date, but
acceptance of payment of this charge shall not waive any Default under this
Note.

The term "Maximum Rate", as used herein, shall mean at the particular time in
question the maximum nonusurious rate of interest which, under applicable law,
may then be charged on this Note. If such maximum rate of interest changes after
the date hereof, the Maximum Rate shall be automatically increased or decreased,
as the case may be, without notice to the undersigned from time to time as of
the effective date of each change in such maximum rate.

The principal amount payable under this Note shall be the sum of all advances
made by the Bank to or at the request of the undersigned, less principal
payments actually received in cash by the Bank. The books and records of the
Bank shall be the best evidence of the principal amount and the unpaid interest
amount owing at any time under this Note and shall be conclusive absent manifest
error. No interest shall accrue under this Note until the date of the first
advance made by the Bank; after that interest on all advances shall accrue and
be computed on the principal balance outstanding from time to time under this
Note until the same is paid in full.

This Note and any other indebtedness and liabilities of any kind of the
undersigned (or any of them) to the Bank, and any and all modifications,
renewals or extensions of it, whether joint or several, contingent or absolute,
now existing or later arising, and however evidenced and whether incurred
voluntarily or involuntarily, known or unknown, or originally payable to the
Bank or to a third party and subsequently acquired by Bank including, without
limitation, any late charges; loan fees or charges; overdraft indebtedness;
costs incurred by Bank in establishing, determining, continuing or defending the
validity or priority of any security interest, pledge or other lien or in
pursuing any of its rights or remedies under any loan document (or otherwise) or
in connection with any proceeding involving the Bank as a result of any
financial accommodation to the undersigned (or any of them); and reasonable
costs and expenses of attorneys and paralegals, whether inside or outside
counsel is used, and whether any suit or other action is instituted, and to
court costs if suit or action is instituted, and whether any such fees, costs or
expenses are incurred at the trial court level or on appeal, in bankruptcy, in
administrative proceedings, in probate proceedings or otherwise (collectively
"Indebtedness") are secured by and the Bank is granted a security interest in
all items deposited in any account of any of the undersigned with the Bank and
by all proceeds of these items (cash or otherwise), all account balances of any
of the undersigned from time to time with the Bank, by all property of any of
the undersigned from time to time in the possession of the Bank and by any other
collateral, rights and properties described in each and every deed of trust,
mortgage, security agreement, pledge, assignment and other security or
collateral agreement which has been, or will at any time(s) later be, executed
by any (or all) of the undersigned to or for the benefit of the Bank
(collectively "Collateral"). "Collateral" shall EXCLUDE intellectual property.
Intellectual property includes "Proprietary Information." "Proprietary
Information" shall mean trade secrets, confidential knowledge, data, or any
other proprietary information of the undersigned and each of its subsidiaries or
affiliated companies. By way of illustration but not limitation. "Proprietary
Information" includes (a) inventions, trade secrets, ideas, concepts, processes,
formulas, data, lists, software programs, all other works of authorship, mask
works, proprietary test tooling, know-how, improvements, discoveries,
developments, designs, and techniques relating to the business or proposed
business of the undersigned whether or not any of the foregoing is or are
patentable, copyrightable, or registrable under any intellectual property laws
and (b) information owned by the undersigned or licensed from third parties
regarding plans for research, development, products, services, marketing and
selling, business plans, budgets and unpublished financial statements, licenses,
prices and costs, suppliers, customers, customer lists (except to the extent
necessary for Bank to perfect or exercise its lien on the undersigned's accounts
receivable), information regarding the skills and compensation of other
employees of the undersigned and (c) intellectual property of third parties in
the undersigned's possession.

<Page>

If an "Event of Default" (as defined in the Credit Agreement of even date
herewith between the undersigned and the Bank, as from time to time amended,
modified or restated) occurs then the Bank may at its option and without prior
notice to the undersigned (or any of them), declare any or all of the
Indebtedness to be immediately due and payable (notwithstanding any provisions
contained in the evidence of it to the contrary), cease advancing money or
extending credit to or for the benefit of the undersigned under this Note or any
other agreement between the undersigned and Bank, terminate this Note as to any
future liability or obligation of Bank, but without affecting Bank's rights and
security interests in any Collateral or the Indebtedness , sell or liquidate all
or any portion of the Collateral, set off against the Indebtedness any amounts
owing by the Bank to the undersigned (or any of them), charge interest at the
default rate provided in the document evidencing the relevant Indebtedness and
exercise any one or more of the rights and remedies granted to the Bank by any
agreement with the undersigned (or any of them) or given to it under applicable
law. All payments under this Note shall be in immediately available United
States funds, without setoff or counterclaim .

If this Note is signed by two or more parties (whether by all as makers or by
one or more as an accommodation party or otherwise), the obligations and
undertakings under this Note shall be that of all and any two or more jointly
and also of each severally. This Note shall bind the undersigned, and the
undersigned's respective heirs, personal representatives, successors and
assigns.

The undersigned waive(s) presentment, demand, protest, notice of dishonor,
notice of demand or intent to demand, notice of acceleration or intent to
accelerate, and all other notices and agree(s) that no extension or indulgence
to the undersigned (or any of them) or release, substitution or nonenforcement
of any security, or release or substitution of any of the undersigned, any
guarantor or any other party, whether with or without notice, shall affect the
obligations of any of the undersigned. The undersigned waive(s) all defenses or
right to discharge available under Section 3-605 of the Texas Uniform Commercial
Code and waive(s) all other suretyship defenses or right to discharge. The
undersigned agree(s) that the Bank has the right to sell, assign, or grant
participations, or any interest, in any or all of the Indebtedness, and that, in
connection with this right, but without limiting its ability to make other
disclosures to the full extent allowable, the Bank may disclose all documents
and information which the Bank now or later has relating to the undersigned or
the Indebtedness. The undersigned agree(s) that the Bank may provide information
relating to the Note or to the undersigned to the Bank's parent, affiliates,
subsidiaries and service providers.

The undersigned agree(s) to reimburse the holder or owner of this Note for
any and all costs and expenses (including without limit, court costs, legal
expenses and reasonable attorney fees, whether inside or outside counsel is
used, whether or not suit is instituted and, if suit is instituted, whether
at the trial court level, appellate level, in a bankruptcy, probate or
administrative proceeding or otherwise) incurred in collecting or attempting
to collect this Note or incurred in any other matter or proceeding relating
to this Note.

The undersigned acknowledge(s) and agree(s) that there are no contrary
agreements, oral or written, establishing a term of this Note and agree(s) that
the terms and conditions of this Note may not be amended, waived or modified
except in a writing signed by an officer of the Bank expressly stating that the
writing constitutes an amendment, waiver or modification of the terms of this
Note. As used in this Note, the word "undersigned" means, individually and
collectively, each maker, accommodation party, indorser and other party signing
this Note in a similar capacity. If any provision of this Note is unenforceable
in whole or part for any reason, the remaining provisions shall continue to be
effective. Chapter 346 of the Texas Finance Code (and as the same may be
incorporated by reference in other Texas statutes) shall not apply to the
Indebtedness evidenced by this Note. THIS NOTE IS MADE IN THE STATE OF TEXAS AND
SHALL BE GOVERNED BY AND CONSTRUED IN ACCORDANCE WITH THE INTERNAL LAWS OF THE
STATE OF TEXAS, WITHOUT REGARD TO CONFLICT OF LAWS PRINCIPLES.

This Note and all other documents, instruments and agreements evidencing,
governing, securing, guaranteeing or otherwise relating to or executed
pursuant to or in connection with this Note or the Indebtedness evidenced
hereby (whether executed and delivered prior to, concurrently with or
subsequent to this Note), as such documents may have been or may hereafter be
amended from time to time (the "Loan Documents") are intended to be performed
in accordance with, and only to the extent permitted by, all applicable usury
laws. If any provision hereof or of any of the other Loan Documents or the
application thereof to any person or circumstance shall, for any reason and
to any extent, be invalid or unenforceable, neither the application of such
provision to any other person or circumstance nor the remainder of the
instrument in which such provision is contained shall be affected thereby and
shall be enforced to the greatest extent permitted by law. It is expressly
stipulated and agreed to be the intent of the holder hereof to at all times
comply with the usury and other applicable laws now or hereafter governing
the interest payable on the indebtedness evidenced by this Note. If the
applicable law is ever revised, repealed or judicially interpreted so as to
render usurious any amount called for under this Note or under any of the
other Loan Documents, or contracted for, charged, taken, reserved or received
with respect to the indebtedness evidenced by this Note, or if Bank's
exercise of the option to accelerate the maturity of this Note, or if any
prepayment by the undersigned or prepayment agreement results (or would, if
complied with, result) in the undersigned having paid, contracted for or
being charged for any interest in excess of that permitted by law, then it is
the express intent of the undersigned and Bank that this Note and the other
Loan Documents shall be limited to the extent necessary to prevent such
result and all excess amounts theretofore collected by Bank shall be credited
on the principal balance of this Note or, if fully paid, upon such other
Indebtedness as shall then remaining outstanding (or, if this Note and all
other Indebtedness have been paid in full, refunded to the undersigned), and
the provisions of this Note and the other Loan Documents shall immediately be
deemed reformed and the amounts thereafter collectable hereunder and
thereunder reduced, without the necessity of the execution of any new
document, so as to comply with the then applicable law, but so as to permit
the recovery of the fullest amount otherwise called for hereunder or
thereunder. All sums paid, or agreed to be paid, by the undersigned for the
use, forbearance, detention, taking, charging, receiving or reserving of the
indebtedness of the undersigned to Bank under this Note or arising under or
pursuant to the other Loan Documents shall, to the maximum extent permitted
by applicable law, be amortized, prorated, allocated and spread throughout
the full term of such indebtedness until payment in full so that the rate or
amount of interest on account of such indebtedness does not exceed the usury
ceiling from time to time in effect and applicable to such indebtedness for
so long as such indebtedness is outstanding. To the extent federal law
permits Bank to contract for, charge or receive a greater amount of interest,
Bank will rely on federal law instead of the Texas Finance Code for the
purpose of determining the maximum Rate.

                                       2
<Page>

Additionally, to the maximum extent permitted by applicable law now or
hereafter in effect, Bank may, at its option and from time to time, implement
any other method of computing the Maximum Rate under the Texas Finance Code
or under other applicable law, by giving notice, if required, to the
undersigned as provided by applicable law now or hereafter in effect.
Notwithstanding anything to the contrary contained herein or in any of the
other Loan Documents, it is not the intention of Bank to accelerate the
maturity of any interest that has not accrued at the time of such
acceleration or to collect unearned interest at the time of such acceleration.

THE UNDERSIGNED AND THE BANK ACKNOWLEDGE THAT THE RIGHT TO TRIAL BY JURY IS A
CONSTITUTIONAL ONE, BUT THAT IT MAY BE WAIVED, EACH PARTY, AFTER CONSULTING (OR
HAVING HAD THE OPPORTUNITY TO CONSULT) WITH COUNSEL OF THEIR CHOICE, KNOWINGLY
AND VOLUNTARILY, AND FOR THEIR MUTUAL BENEFIT, WAIVES ANY RIGHT TO TRIAL BY JURY
IN THE EVENT OF LITIGATION REGARDING THE PERFORMANCE OR ENFORCEMENT OF, OR IN
ANY WAY RELATED TO, THIS NOTE OR THE INDEBTEDNESS.

THIS WRITTEN LOAN AGREEMENT (AS DEFINED BY SECTION 26.02 OF THE TEXAS BUSINESS
AND COMMERCE CODE) REPRESENTS THE FINAL AGREEMENT BETWEEN THE PARTIES AND MAY
NOT BE CONTRADICTED BY EVIDENCE OF PRIOR, CONTEMPORANEOUS OR SUBSEQUENT ORAL
AGREEMENTS OF THE PARTIES. THERE ARE NO UNWRITTEN ORAL AGREEMENTS BETWEEN THE
PARTIES.

<Table>
<S><C>
Silicon Laboratories Inc.    By:  /s/ Navdeep Sooch             Its: Chief Executive Officer
--------------------------       ----------------------------        -----------------------
OBLIGOR NAME TYPED/PRINTED       SIGNATURE OF                        TITLE (if applicable)

                             By:  /s/ John W. McGovern          Its: Chief Financial Officer
                                 ----------------------------        -----------------------
                                 SIGNATURE OF                        TITLE (if applicable)

                             By:                                Its:
                                 ----------------------------        -----------------------
                                 SIGNATURE OF                        TITLE (if applicable)

          4635 Boston Lane         Austin         Texas        Travis         78735
--------------------------------------------------------------------------------------------
Street Address                      City          State        Country       Zip Code

</Table>

<Table>
<Caption>
<S>                         <C>                   <C>                  <C>           <C>
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                 For Bank Use Only                                     CCAR#
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Loan Officer Initials       Loan Group name       Obligor(s) Name
--------------------------------------------------------------------------------------------
Loan Officer I.D. No.       Loan Group No.        Obligor #            Note #        Amount
--------------------------------------------------------------------------------------------
</Table>


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