SIGMATEL, INC. (Delaware corporation) 10,000,000 Shares of Common Stock PURCHASE AGREEMENT

Exhibit 1.1

SIGMATEL, INC.

(Delaware corporation)

10,000,000 Shares of Common Stock

PURCHASE AGREEMENT

Dated: September , 2003

SIGMATEL, INC.

(Delaware corporation)

10,000,000 Shares of Common Stock

(Par Value $0.0001 Per Share)

PURCHASE AGREEMENT

September , 2003

▇▇▇▇▇▇▇ ▇▇▇▇▇ & CO.

▇▇▇▇▇▇▇ Lynch, Pierce, ▇▇▇▇▇▇ & ▇▇▇▇▇

Incorporated

▇.▇. ▇▇▇▇▇▇ Securities Inc.

CIBC World Markets Corp.

▇▇▇▇▇▇▇ & Company, Inc.

as Representatives of the several Underwriters

▇/▇

▇▇▇▇▇▇▇ ▇▇▇▇▇ & ▇▇.

▇▇▇▇▇▇▇ Lynch, Pierce, ▇▇▇▇▇▇ & ▇▇▇▇▇

Incorporated

▇ ▇▇▇▇▇ ▇▇▇▇▇▇▇▇▇ ▇▇▇▇▇▇

▇▇▇ ▇▇▇▇, ▇▇▇ ▇▇▇▇ ▇▇▇▇▇

Ladies and Gentlemen:

SigmaTel, Inc., a Delaware corporation (the “Company”), and the persons listed on Schedule B hereto (the “Selling Stockholders”), confirm their respective agreements with ▇▇▇▇▇▇▇ ▇▇▇▇▇ & Co., ▇▇▇▇▇▇▇ Lynch, Pierce, ▇▇▇▇▇▇ & ▇▇▇▇▇ Incorporated (“▇▇▇▇▇▇▇ ▇▇▇▇▇”) and each of the other Underwriters named in Schedule A hereto (collectively, the “Underwriters”, which term shall also include any underwriter substituted as hereinafter provided in Section 10 hereof), for whom ▇▇▇▇▇▇▇ ▇▇▇▇▇, ▇.▇. ▇▇▇▇▇▇ Securities Inc., CIBC World Markets Corp., and ▇▇▇▇▇▇▇ & Company, Inc. are acting as Representatives (in such capacity, the “Representatives”), with respect to (i) the sale by the Company and the Selling Stockholders, acting severally and not jointly, and the purchase by the Underwriters, acting severally and not jointly, of the respective numbers of shares of Common Stock, par value $0.0001 per share, of the Company (“Common Stock”) set forth in said Schedules A and B hereto, and (ii) the grant by the Company and the Selling Stockholders to the Underwriters, acting severally and not jointly, of the option described in Section 2(b) hereof to purchase all or any part of 1,500,000 additional shares of Common Stock to cover overallotments, if any. The aforesaid 10,000,000 shares of Common Stock (the “Initial Securities”) to be purchased by the Underwriters and all or any part of the 1,500,000 shares of Common Stock subject to the option described in Section 2(b) hereof (the “Option Securities”) are hereinafter called, collectively, the “Securities”.

The Company and the Selling Stockholders understand that the Underwriters propose to make a public offering of the Securities as soon as the Representatives deem advisable after this Agreement has been executed and delivered.

The Company has filed with the Securities and Exchange Commission (the “Commission”) a registration statement on Form S-1 (No. 333-106796), including the related preliminary prospectus or prospectuses, covering the registration of the Securities under the Securities Act of 1933, as amended (the “1933 Act”). Promptly after execution and delivery of this Agreement, the Company will prepare and file a prospectus in accordance with the provisions of Rule 430A (“Rule 430A”) of the rules and regulations

of the Commission under the 1933 Act (the “1933 Act Regulations”) and paragraph (b) of Rule 424 (“Rule 424(b)”) of the 1933 Act Regulations. The information included in such prospectus that was omitted from such registration statement at the time it became effective but that is deemed to be part of such registration statement at the time it became effective pursuant to paragraph (b) of Rule 430A is referred to as “Rule 430A Information.” Each prospectus used before such registration statement became effective, and any prospectus that omitted the Rule 430A Information, that was used after such effectiveness and prior to the execution and delivery of this Agreement, is herein called a “preliminary prospectus.” Such registration statement, including the exhibits and any schedules thereto, at the time it became effective, and including the Rule 430A Information, is herein called the “Registration Statement.” Any registration statement filed pursuant to Rule 462(b) of the 1933 Act Regulations is herein referred to as the “Rule 462(b) Registration Statement,” and after such filing the term “Registration Statement” shall include the Rule 462(b) Registration Statement. The final prospectus in the form first furnished to the Underwriters for use in connection with the offering of the Securities is herein called the “Prospectus.” For purposes of this Agreement, all references to the Registration Statement, any preliminary prospectus, the Prospectus or any amendment or supplement to any of the foregoing shall be deemed to include the copy filed with the Commission pursuant to its Electronic Data Gathering, Analysis and Retrieval system (“▇▇▇▇▇”).

SECTION 1. Representations and Warranties.

(a) Representations and Warranties by the Company. The Company represents and warrants to each Underwriter as of the date hereof, as of the Closing Time referred to in Section 2(c) hereof, and as of each Date of Delivery (if any) referred to in Section 2(b) hereof, and agrees with each Underwriter, as follows:

(i) Compliance with Registration Requirements. Each of the Registration Statement and any Rule 462(b) Registration Statement and any post-effective amendment thereto has become effective under the 1933 Act and no stop order suspending the effectiveness of the Registration Statement, any Rule 462(b) Registration Statement or any post-effective amendment thereto has been issued under the 1933 Act and no proceedings for that purpose have been instituted or are pending or, to the knowledge of the Company, are contemplated by the Commission, and any request on the part of the Commission for additional information has been complied with.

At the respective times the Registration Statement, any Rule 462(b) Registration Statement and any post-effective amendments thereto became effective and at the Closing Time (and, if any Option Securities are purchased, at the Date of Delivery), the Registration Statement, the Rule 462(b) Registration Statement and any amendments and supplements thereto complied and will comply in all material respects with the requirements of the 1933 Act and the 1933 Act Regulations and did not and will not contain an untrue statement of a material fact or omit to state a material fact required to be stated therein or necessary to make the statements therein not misleading. Neither the Prospectus nor any amendments or supplements thereto, at the time the Prospectus or any such amendment or supplement was issued and at the Closing Time (and, if any Option Securities are purchased, at the Date of Delivery), included or will include an untrue statement of a material fact or omitted or will omit to state a material fact necessary in order to make the statements therein, in the light of the circumstances under which they were made, not misleading. The representations and warranties in this subsection shall not apply to statements in or omissions from the Registration Statement or Prospectus made in reliance upon and in conformity with written information furnished to the Company by any Underwriter through ▇▇▇▇▇▇▇ ▇▇▇▇▇ expressly for use in the Registration Statement (or any amendment thereto) or the Prospectus (or any amendment or supplement thereto).

Each preliminary prospectus and the prospectus filed as part of the Registration Statement as originally filed or as part of any amendment thereto complied when so filed in all material respects with the 1933 Act Regulations and each preliminary prospectus and the Prospectus delivered to the Underwriters for use in connection with this offering was identical to the electronically transmitted copies thereof filed with the Commission pursuant to ▇▇▇▇▇, except to the extent permitted by Regulation S-T.

(ii) Independent Accountants. The accountants who certified the financial statements and supporting schedules included in the Registration Statement are independent public accountants as required by the 1933 Act and the 1933 Act Regulations.

(iii) Financial Statements. The financial statements included in the Registration Statement and the Prospectus, together with the related schedules and notes, present fairly the financial position of the Company at the dates indicated and the statement of operations, stockholders’ equity and cash flows of the Company for the periods specified; said financial statements have been prepared in conformity with generally accepted accounting principles (“GAAP”) applied on a consistent basis throughout the periods involved. The supporting schedules included in the Registration Statement present fairly in accordance with GAAP the information required to be stated therein. The selected financial data and the summary financial information included in the Prospectus present fairly the information shown therein and have been compiled on a basis consistent with that of the audited financial statements included in the Registration Statement. The pro forma financial statements and the related notes thereto included in the Registration Statement and the Prospectus present fairly the information shown therein, have been prepared in accordance with the Commission’s rules and guidelines with respect to pro forma financial statements and have been properly compiled on the bases described therein, and the assumptions used in the preparation thereof are reasonable and the adjustments used therein are appropriate to give effect to the transactions and circumstances referred to therein.

(iv) No Material Adverse Change in Business. Since the respective dates as of which information is given in the Registration Statement and the Prospectus, except as otherwise stated therein, (A) there has been no material adverse change in the condition, financial or otherwise, or in the earnings, business affairs or business prospects of the Company, whether or not arising in the ordinary course of business (a “Material Adverse Effect”), (B) there have been no transactions entered into by the Company, other than those in the ordinary course of business, which are material with respect to the Company, and (C) there has been no dividend or distribution of any kind declared, paid or made by the Company on any class of its capital stock.

(v) Good Standing of the Company. The Company has been duly organized and is validly existing as a corporation in good standing under the laws of the State of Delaware and has corporate power and authority to own, lease and operate its properties and to conduct its business as described in the Prospectus and to enter into and perform its obligations under this Agreement; and the Company is duly qualified as a foreign corporation to transact business and is in good standing in each other jurisdiction in which such qualification is required, whether by reason of the ownership or leasing of property or the conduct of business, except where the failure so to qualify or to be in good standing would not result in a Material Adverse Effect.

(vi) No Subsidiaries. The Company has no subsidiaries.

(vii) Capitalization. The authorized, issued and outstanding capital stock of the Company is as set forth in the Prospectus in the column entitled “Actual” under the caption “Capitalization” (except for subsequent issuances, if any, pursuant to this Agreement, pursuant to

employee benefit plans described in the Prospectus or pursuant to the exercise of options or warrants described in the Prospectus). The shares of issued and outstanding capital stock of the Company, including the Securities to be purchased by the Underwriters from the Selling Stockholders, have been duly authorized and validly issued and are fully paid and non-assessable; none of the outstanding shares of capital stock of the Company, including the Securities to be purchased by the Underwriters from the Selling Stockholders, was issued in violation of the preemptive or other similar rights of any securityholder of the Company.

(viii) Authorization of Agreement. This Agreement has been duly authorized, executed and delivered by the Company.

(ix) Authorization and Description of Securities. The Securities have been duly authorized for issuance and sale to the Underwriters pursuant to this Agreement and, when issued and delivered by the Company pursuant to this Agreement against payment of the consideration set forth herein, will be validly issued and fully paid and non-assessable; the Common Stock conforms to all statements relating thereto contained in the Prospectus and such description conforms to the rights set forth in the instruments defining the same; no holder of the Securities will be subject to personal liability by reason of being such a holder; and the issuance of the Securities is not subject to the preemptive or other similar rights of any securityholder of the Company.

(x) Absence of Defaults and Conflicts. The Company is not in violation of its charter or by-laws or in default in the performance or observance of any obligation, agreement, covenant or condition contained in any contract, indenture, mortgage, deed of trust, loan or credit agreement, note, lease or other agreement or instrument to which the Company is a party or by which it may be bound, or to which any of the property or assets of the Company is subject (collectively, “Agreements and Instruments”) except for such defaults that would not result in a Material Adverse Effect; and the execution, delivery and performance of this Agreement and the consummation of the transactions contemplated herein and in the Registration Statement (including the issuance and sale of the Securities and the use of the proceeds from the sale of the Securities as described in the Prospectus under the caption “Use of Proceeds”) and compliance by the Company with its obligations hereunder have been duly authorized by all necessary corporate action and do not and will not, whether with or without the giving of notice or passage of time or both, conflict with or constitute a breach of, or default or Repayment Event (as defined below) under, or result in the creation or imposition of any lien, charge or encumbrance upon any property or assets of the Company pursuant to, the Agreements and Instruments (except for such conflicts, breaches, defaults or Repayment Events or liens, charges or encumbrances that would not result in a Material Adverse Effect), nor will such action result in any violation of the provisions of the charter or by-laws of the Company or any applicable law, statute, rule, regulation, judgment, order, writ or decree of any government, government instrumentality or court, domestic or foreign, having jurisdiction over the Company or any of its assets, properties or operations. As used herein, a “Repayment Event” means any event or condition which gives the holder of any note, debenture or other evidence of indebtedness (or any person acting on such holder’s behalf) the right to require the repurchase, redemption or repayment of all or a portion of such indebtedness by the Company.

(xi) Absence of Labor Dispute. No labor dispute with the employees of the Company exists or, to the knowledge of the Company, is imminent, and the Company is not aware of any existing or imminent labor disturbance by the employees of any of its principal suppliers, manufacturers, customers or contractors, which, in either case, would result in a Material Adverse Effect.

(xii) Absence of Proceedings. There is no action, suit, proceeding, inquiry or investigation before or brought by any court or governmental agency or body, domestic or foreign, now pending, or, to the knowledge of the Company, threatened, against or affecting the Company which is required to be disclosed in the Registration Statement (other than as disclosed therein), or which might result in a Material Adverse Effect, or which might materially and adversely affect the property or assets of the Company or the consummation of the transactions contemplated in this Agreement or the performance by the Company of its obligations hereunder; the aggregate of all pending legal or governmental proceedings to which the Company is a party or of which its property or assets is the subject which are not described in the Registration Statement, including ordinary routine litigation incidental to the business, could not reasonably be expected to result in a Material Adverse Effect.

(xiii) Accuracy of Exhibits. There are no contracts or documents which are required to be described in the Registration Statement or the Prospectus or to be filed as exhibits thereto which have not been so described and filed as required.

(xiv) Possession of Intellectual Property. The Company owns or possesses, or can acquire on reasonable terms, adequate patents, patent rights, licenses, inventions, copyrights, know-how (including trade secrets and other unpatented and/or unpatentable proprietary or confidential information, systems or procedures), trademarks, service marks, trade names or other intellectual property (collectively, “Intellectual Property”) necessary to carry on the business now operated by it, and the Company has not received any notice or is not otherwise aware of any infringement of or conflict with asserted rights of others with respect to any Intellectual Property or of any facts or circumstances which would render any Intellectual Property invalid or inadequate to protect the interest of the Company therein, and which infringement or conflict (if the subject of any unfavorable decision, ruling or finding) or invalidity or inadequacy, singly or in the aggregate, would result in a Material Adverse Effect.

(xv) Absence of Further Requirements. No filing with, or authorization, approval, consent, license, order, registration, qualification or decree of, any court or governmental authority or agency is necessary or required for the performance by the Company of its obligations hereunder, in connection with the offering, issuance or sale of the Securities hereunder or the consummation of the transactions contemplated by this Agreement, except such as have been already obtained or as may be required under the 1933 Act or the 1933 Act Regulations or state securities laws.

(xvi) Absence of Manipulation. Neither the Company nor any affiliate of the Company has taken, nor will the Company or any affiliate take, directly or indirectly, any action which is designed to or which has constituted or which would be expected to cause or result in stabilization or manipulation of the price of any security of the Company to facilitate the sale or resale of the Securities.

(xvii) Possession of Licenses and Permits. The Company possesses such permits, licenses, approvals, consents and other authorizations (collectively, “Governmental Licenses”) issued by the appropriate federal, state, local or foreign regulatory agencies or bodies necessary to conduct the business now operated by them, except where the failure so to possess would not, singly or in the aggregate, result in a Material Adverse Effect; the Company is in compliance with the terms and conditions of all such Governmental Licenses, except where the failure so to comply would not, singly or in the aggregate, result in a Material Adverse Effect; all of the Governmental Licenses are valid and in full force and effect, except when the invalidity of such Governmental Licenses or the failure of such Governmental Licenses to be in full force and effect

would not, singly or in the aggregate, result in a Material Adverse Effect; and the Company has not received any notice of proceedings relating to the revocation or modification of any such Governmental Licenses which, singly or in the aggregate, if the subject of an unfavorable decision, ruling or finding, would result in a Material Adverse Effect.

(xviii) Title to Property. The Company has good and marketable title to all real property owned by the Company and good title to all other properties owned by it, in each case, free and clear of all mortgages, pledges, liens, security interests, claims, restrictions or encumbrances of any kind except such as (a) are described in the Prospectus or (b) do not, singly or in the aggregate, materially affect the value of such property and do not interfere with the use made and proposed to be made of such property by the Company; and all of the leases and subleases material to the business of the Company and under which the Company holds properties described in the Prospectus, are in full force and effect, and the Company does not have any notice of any material claim of any sort that has been asserted by anyone adverse to the rights of the Company under any of the leases or subleases mentioned above, or affecting or questioning the rights of the Company to the continued possession of the leased or subleased premises under any such lease or sublease.

(xix) Investment Company Act. The Company is not required, and upon the issuance and sale of the Securities as herein contemplated and the application of the net proceeds therefrom as described in the Prospectus will not be required, to register as an “investment company” under the Investment Company Act of 1940, as amended (the “1940 Act”).

(xx) Environmental Laws. Except as would not, singly or in the aggregate, result in a Material Adverse Effect, (A) the Company is not in violation of any federal, state, local or foreign statute, law, rule, regulation, ordinance, code, policy or rule of common law or any judicial or administrative interpretation thereof, including any judicial or administrative order, consent, decree or judgment, relating to pollution or protection of human health, the environment (including, without limitation, ambient air, surface water, groundwater, land surface or subsurface strata) or wildlife, including, without limitation, laws and regulations relating to the release or threatened release of chemicals, pollutants, contaminants, wastes, toxic substances, hazardous substances, petroleum or petroleum products, asbestos-containing materials or mold (collectively, “Hazardous Materials”) or to the manufacture, processing, distribution, use, treatment, storage, disposal, transport or handling of Hazardous Materials (collectively, “Environmental Laws”), (B) the Company has all permits, authorizations and approvals required under any applicable Environmental Laws and are each in compliance with their requirements, (C) there are no pending or threatened administrative, regulatory or judicial actions, suits, demands, demand letters, claims, liens, notices of noncompliance or violation, investigation or proceedings relating to any Environmental Law against the Company and (D) there are no events or circumstances that would reasonably be expected to form the basis of an order for clean-up or remediation, or an action, suit or proceeding by any private party or governmental body or agency, against or affecting the Company relating to Hazardous Materials or any Environmental Laws.

(xxi) Registration Rights. Except as described in the Prospectus, there are no persons with registration rights or other similar rights to have any securities registered pursuant to the Registration Statement or otherwise registered by the Company under the 1933 Act. All registration rights or other similar rights to have any securities registered pursuant to the Registration Statement have been waived.

(xxii) Insurance. The Company carries, or is covered by, insurance with insurers of recognized reputability in such amounts and covering such risks as it believes is commercially

reasonable in light of the business presently conducted by the Company, all of which insurance is in full force and effect, and the Company has no reason to believe that it will not be able to renew its existing insurance coverage as and when such coverage expires or to obtain similar coverage from similar insurers at a cost, that would not, single or in the aggregate, have a Material Adverse Effect, and there are no claims by the Company of any material amount under any such policy as to which any insurer is denying liability or defending under a reservation of rights claim and the Company has not received notice from any insurer or agent of such insurer that substantial capital improvements or other material expenditures will have to be made in order to continue such insurance.

(xxiii) Accounting Controls. The Company maintains a system of internal accounting controls sufficient to provide reasonable assurances that (i) transactions are executed in accordance with management’s general or specific authorization; (ii) transactions are recorded as necessary to permit preparation of financial statements in conformity with generally accepted accounting principles and to maintain accountability for assets; (iii) access to assets is permitted only in accordance with management’s general or specific authorization; and (iv) the recorded accountability for assets is compared with existing assets at reasonable intervals and appropriate action is taken with respect to any differences.

(b) Representations and Warranties by the Selling Stockholders. Each Selling Stockholder severally represents and warrants to each Underwriter as of the date hereof, as of the Closing Time, and, if such Selling Stockholder is selling Option Securities on a Date of Delivery, as of each such Date of Delivery, and agrees with each Underwriter, as follows:

(i) Authorization of this Agreement. This Agreement has been duly authorized, executed and delivered by or on behalf of such Selling Stockholder.

(ii) Authorization of Power of Attorney and Custody Agreement. Each of the Power of Attorney and Custody Agreement, in the forms heretofore furnished to the Representatives (collectively, the “Power of Attorney and Custody Agreement”), has been duly authorized, executed and delivered by such Selling Stockholder and, assuming the due authorization, execution and delivery by the other parties thereto, is the valid and binding agreement of such Selling Stockholder.

(iii) Noncontravention. The execution and delivery of this Agreement and the Power of Attorney and Custody Agreement and the sale and delivery of the Securities to be sold by such Selling Stockholder and the consummation of the transactions contemplated herein and compliance by such Selling Stockholder with its obligations hereunder do not and will not, whether with or without the giving of notice or passage of time or both, conflict with or constitute a breach of, or default under, or result in the creation or imposition of any tax, lien, charge or encumbrance upon the Securities to be sold by such Selling Stockholder pursuant to any contract, indenture, mortgage, deed of trust, loan or credit agreement, note, license, lease or other agreement or instrument to which such Selling Stockholder is a party or by which such Selling Stockholder may be bound, or to which any of the property or assets of such Selling Stockholder is subject (except for such conflicts, breaches or defaults that would not adversely affect such Selling Stockholder’s ability to fulfill its obligations hereunder or under the Power of Attorney and Custody Agreement), nor will such action result in any violation of the provisions of the charter or by-laws or other organizational instrument of such Selling Stockholder, if applicable, or any applicable treaty, law, statute, rule, regulation, judgment, order, writ or decree of any government, government instrumentality or court, domestic or foreign, having jurisdiction over such Selling Stockholder or any of its properties (except for violations of any treaty, law, statute,

rule, regulation, judgment, order, writ or decree that would not adversely affect such Selling Stockholder’s ability to fulfill its obligations hereunder or under the Power of Attorney and Custody Agreement).

(iv) Certificates Suitable for Transfer. The Securities to be sold by such Selling Stockholder pursuant to this Agreement are certificated securities in registered form and are not held in any securities account or by or through any securities intermediary within the meaning of the Uniform Commercial Code as in effect in the State of New York (the “UCC”). Certificates for all of the Securities to be sold by such Selling Stockholder pursuant to this Agreement (or convertible promissory notes or warrants to acquire the Securities together with a properly executed conversion notice or exercise notice, as the case may be, to convert such notes and/or exercise such warrants for Securities), in suitable form for transfer by delivery or accompanied by duly executed instruments of transfer or assignment in blank with signatures guaranteed, have been placed in custody with Computershare Investor Services LLC (the “Custodian”) with irrevocable instructions to deliver such Securities to the Underwriters pursuant to this Agreement.

(v) Valid Title. Such Selling Stockholder has, and at the Closing Time, and, if such Selling Stockholder is selling Option Securities on a Date of Delivery, as of each such Date of Delivery, will have, valid title to the Securities to be sold by such Selling Stockholder free and clear of all security interests, claims, liens, equities or other encumbrances, other than pursuant to this Agreement and other than those arising from the lockup agreements contemplated by Section 5(k) hereof, and all right, power and authority, to enter into this Agreement and the Power of Attorney and Custody Agreement and to sell, transfer and deliver the Securities to be sold by such Selling Stockholder to the Underwriters in accordance with the terms hereof.

(vi) Delivery of Securities. Upon the Underwriters acquiring possession of the Securities to be sold by such Selling Stockholder and paying the purchase price therefor pursuant to this Agreement, the Underwriters (assuming that no such Underwriter has notice of any “adverse claim”, within the meaning of Section 8-105 of the UCC, to such Securities) will acquire their respective interests in such Securities (including, without limitation, all rights that such Selling Stockholder had or has the power to transfer in such Securities) free and clear of any adverse claim within the meaning of Section 8-102 of the UCC.

(vii) Absence of Manipulation. Such Selling Stockholder has not taken, and will not take, directly or indirectly, any action which is designed to or which has constituted or which might reasonably be expected to cause or result in stabilization or manipulation of the price of any security of the Company to facilitate the sale or resale of the Securities.

(viii) Absence of Further Requirements. No filing with, or consent, approval, authorization, order, registration, qualification or decree of, any court or governmental authority or agency, domestic or foreign, is necessary or required for the performance by such Selling Stockholder of its obligations hereunder or under the Power of Attorney and Custody Agreement, or in connection with the sale and delivery of the Securities hereunder or the consummation of the transactions contemplated by this Agreement, except such as may have previously been made or obtained or as may be required under the 1933 Act or the 1933 Act Regulations or state securities laws or pursuant to the rules of the National Association of Securities Dealers, Inc. (the “NASD”).

(ix) Restriction on Sale of Securities. During a period of 180 days from the date of the Prospectus, such Selling Stockholder will not, without the prior written consent of ▇▇▇▇▇▇▇ ▇▇▇▇▇, (i) offer, pledge, sell, contract to sell, sell any option or contract to purchase, purchase any

option or contract to sell, grant any option, right or warrant to purchase or otherwise transfer or dispose of, directly or indirectly, any share of Common Stock or any securities convertible into or exercisable or exchangeable for Common Stock or file, or cause to be filed, any registration statement under the 1933 Act with respect to any of the foregoing or (ii) enter into any swap or any other agreement or any transaction that transfers, in whole or in part, directly or indirectly, the economic consequence of ownership of the Common Stock, whether any such swap or transaction described in clause (i) or (ii) above is to be settled by delivery of Common Stock or such other securities, in cash or otherwise. The foregoing sentence shall not apply to (i) the Securities to be sold hereunder, (ii) transfers of Common Stock or other securities of the Company as a bona fide gift or gifts, provided that the donee or donees thereof agree to be bound in writing by the restrictions set forth in this paragraph, (iii) transfers of Common Stock or other securities of the Company as a distribution by a Selling Stockholder that is a partnership to any partner of such partnership or by a Selling Stockholder that is a limited liability company to any member of such limited liability company, provided that any such distributee agrees to be bound in writing by the restrictions set forth in this paragraph, (iv) the conversion of convertible promissory notes of the Company or the exercise of warrants of the Company (in each case as described in the Prospectus) held by the Selling Stockholders; provided that each of the Selling Stockholders hereby acknowledges and agrees that any shares of securities issued upon conversion of such notes or the exercise of such warrants, and any shares of Common Stock issued or issuable upon conversion of such securities, shall be subject to the restrictions set forth in this paragraph, or (v) transfers of Common Stock or other securities of the Company to any trust for the direct or indirect benefit of a Selling Stockholder or the immediate family of a Selling Stockholder, provided that the trustee of the trust agrees to be bound in writing by the restrictions set forth in this paragraph, and provided further that any such transfer shall not involve a disposition for value. For purposes of this paragraph, “immediate family” shall mean any relationship by blood, marriage or adoption, not more remote than first cousin.

(c) No Association with NASD. Neither such Selling Stockholder nor any of its affiliates directly, or indirectly through one or more intermediaries, controls, or is controlled by, or is under common control with, or is a person associated with (within the meaning of Article I(dd) of the Bylaws of the NASD, any member firm of the NASD, except that each of Chancellor V, L.P., Citiventure 2000, L.P. and Chancellor V-A, L.P. is affiliated or associated with AMVESCAP Services Inc., an NASD member, and TeleSoft Partners IA, L.P may be affiliated or associated with Deutsche Bank Securities Inc., an NASD member.

(d) Officer’s Certificates. Any certificate signed by any officer of the Company delivered to the Representatives or to counsel for the Underwriters shall be deemed a representation and warranty by the Company to each Underwriter as to the matters covered thereby; and any certificate signed by or on behalf of the Selling Stockholders as such and delivered to the Representatives or to counsel for the Underwriters pursuant to the terms of this Agreement shall be deemed a representation and warranty by such Selling Stockholder to the Underwriters as to the matters covered thereby.

SECTION 2. Sale and Delivery to Underwriters; Closing.

(a) Initial Securities. On the basis of the representations and warranties herein contained and subject to the terms and conditions herein set forth, the Company and each Selling Stockholder, severally and not jointly, agree to sell to each Underwriter, severally and not jointly, and each Underwriter, severally and not jointly, agrees to purchase from the Company and each Selling Stockholder, at the price per share set forth in Schedule C, that proportion of the number of Initial Securities set forth in Schedule B opposite the name of the Company or such Selling Stockholder, as the case may be, which the number of Initial Securities set forth in Schedule A opposite the name of such Underwriter, plus any additional

number of Initial Securities which such Underwriter may become obligated to purchase pursuant to the provisions of Section 10 hereof, bears to the total number of Initial Securities, subject, in each case, to such adjustments among the Underwriters and Representatives in their sole discretion shall make to eliminate any sales or purchases of fractional securities.

(b) Option Securities. In addition, on the basis of the representations and warranties herein contained and subject to the terms and conditions herein set forth, the Company and the Selling Stockholders, acting severally and not jointly, hereby grant an option to the Underwriters, severally and not jointly, to purchase up to an additional 1,500,000 shares of Common Stock (with up to 395,293 shares to be sold by the Company and up to 1,104,761 shares to be sold by the Selling Stockhlders) at the price per share set forth in Schedule C, less an amount per share equal to any dividends or distributions declared by the Company and payable on the Initial Securities but not payable on the Option Securities. The option hereby granted will expire 30 days after the date hereof and may be exercised in whole or in part from time to time only for the purpose of covering overallotments which may be made in connection with the offering and distribution of the Initial Securities upon notice by ▇▇▇▇▇▇▇ ▇▇▇▇▇ to the Company setting forth the number of Option Securities as to which the several Underwriters are then exercising the option and the time and date of payment and delivery for such Option Securities. Any such time and date of delivery (a “Date of Delivery”) shall be determined by ▇▇▇▇▇▇▇ ▇▇▇▇▇, but shall not be later than seven full business days after the exercise of said option, nor in any event prior to the Closing Time, as hereinafter defined. If the option is exercised as to all or any portion of the Option Securities, each of the Underwriters, acting severally and not jointly, will purchase that proportion of the total number of Option Securities then being purchased which the number of Initial Securities set forth in Schedule A opposite the name of such Underwriter bears to the total number of Initial Securities, subject in each case to such adjustments as ▇▇▇▇▇▇▇ ▇▇▇▇▇ in its discretion shall make to eliminate any sales or purchases of fractional shares. If the Underwriters elect to purchase less than all of the Option Securities, the first 1,104,761 shares of Option Securities shall be purchased from the Selling Stockholders and the remaining 395,293 shares of Option Securities shall be purchased from the Company. In such event, each Selling Stockholder shall sell a number of Option Securities equal to the total number of Option Securities to be sold by all Selling Stockholders on such Date of Delivery multiplied by the number of Option Securities set forth opposite such Selling Stockholders name on Schedule B divided by 1,104,761.

(c) Payment. Payment of the purchase price for, and delivery of certificates for, the Initial Securities shall be made at the offices of ▇▇▇▇▇▇ ▇▇▇▇▇▇▇ ▇▇▇▇▇▇▇▇ & ▇▇▇▇▇▇, Professional Corporation, 8911 Capital of ▇▇▇▇▇ ▇▇▇▇▇▇▇, ▇▇▇▇▇▇▇ ▇▇▇, ▇▇▇▇▇ ▇▇▇▇, ▇▇▇▇▇▇, ▇▇▇▇▇ ▇▇▇▇▇, or at such other place as shall be agreed upon by the Representatives and the Company, at 9:00 A.M. (Eastern time) on the third (fourth, if the pricing occurs after 4:30 P.M. (Eastern time) on any given day) business day after the date hereof (unless postponed in accordance with the provisions of Section 10), or such other time not later than ten business days after such date as shall be agreed upon by the Representatives and the Company (such time and date of payment and delivery being herein called “Closing Time”).

In addition, in the event that any or all of the Option Securities are purchased by the Underwriters, payment of the purchase price for, and delivery of certificates for, such Option Securities shall be made at the above-mentioned offices, or at such other place as shall be agreed upon by the Representatives and the Company, on each Date of Delivery as specified in the notice from the Representatives to the Company.

Payment shall be made to the Company and the Selling Stockholders by wire transfer of immediately available funds to bank accounts designated by the Company and the Custodian pursuant to each Selling Stockholder’s Power of Attorney and Custody Agreement, as the case may be, against delivery to the Representatives for the respective accounts of the Underwriters of certificates for the Securities to be purchased by them. It is understood that each Underwriter has authorized the

Representatives, for its account, to accept delivery of, receipt for, and make payment of the purchase price for, the Initial Securities and the Option Securities, if any, which it has agreed to purchase. ▇▇▇▇▇▇▇ ▇▇▇▇▇, individually and not as representative of the Underwriters, may (but shall not be obligated to) make payment of the purchase price for the Initial Securities or the Option Securities, if any, to be purchased by any Underwriter whose funds have not been received by the Closing Time or the relevant Date of Delivery, as the case may be, but such payment shall not relieve such Underwriter from its obligations hereunder.

(d) Denominations; Registration. Certificates for the Initial Securities and the Option Securities, if any, shall be in such denominations and registered in such names as the Representatives may request in writing at least one full business day before the Closing Time or the relevant Date of Delivery, as the case may be. The certificates for the Initial Securities and the Option Securities, if any, will be made available for examination and packaging by the Representatives in The City of New York not later than 10:00 A.M. (Eastern time) on the business day prior to the Closing Time or the relevant Date of Delivery, as the case may be.

SECTION 3. Covenants of the Company. The Company covenants with each Underwriter as follows:

(a) Compliance with Securities Regulations and Commission Requests. The Company, subject to Section 3(b), will comply with the requirements of Rule 430A and will notify the Representatives and ▇▇▇▇▇▇▇▇ & ▇▇▇▇▇▇▇▇ LLP, as special counsel to the Selling Stockholders, immediately, and confirm the notice in writing, (i) when any post-effective amendment to the Registration Statement shall become effective, or any supplement to the Prospectus or any amended Prospectus shall have been filed, (ii) of the receipt of any comments from the Commission, (iii) of any request by the Commission for any amendment to the Registration Statement or any amendment or supplement to the Prospectus or for additional information, and (iv) of the issuance by the Commission of any stop order suspending the effectiveness of the Registration Statement or of any order preventing or suspending the use of any preliminary prospectus, or of the suspension of the qualification of the Securities for offering or sale in any jurisdiction, or of the initiation or threatening of any proceedings for any of such purposes. The Company will promptly effect the filings necessary pursuant to Rule 424(b) and will take such steps as it deems necessary to ascertain promptly whether the form of prospectus transmitted for filing under Rule 424(b) was received for filing by the Commission and, in the event that it was not, it will promptly file such prospectus. The Company will make every reasonable effort to prevent the issuance of any stop order and, if any stop order is issued, to obtain the lifting thereof at the earliest possible moment.

(b) Filing of Amendments. The Company will give the Representatives and ▇▇▇▇▇▇▇▇ & ▇▇▇▇▇▇▇▇ LLP, as special counsel to the Selling Stockholders, notice of its intention to file or prepare any amendment to the Registration Statement (including any filing under Rule 462(b)) or any amendment, supplement or revision to either the prospectus included in the Registration Statement at the time it became effective or to the Prospectus will furnish the Representatives and ▇▇▇▇▇▇▇▇ & ▇▇▇▇▇▇▇▇ LLP, as special counsel to the Selling Stockholders, with copies of any such documents a reasonable amount of time prior to such proposed filing or use, as the case may be, and will not file or use any such document to which the Representatives or counsel for the Underwriters shall reasonably object.

(c) Delivery of Registration Statements. The Company has furnished or will deliver to the Representatives and counsel for the Underwriters, without charge, signed copies of the Registration Statement as originally filed and of each amendment thereto (including exhibits filed therewith or incorporated by reference therein) and signed copies of all consents and certificates of experts, and will also deliver to the Representatives, without charge, a conformed copy of the Registration Statement as originally filed and of each amendment thereto (without exhibits) for each of the Underwriters. The

copies of the Registration Statement and each amendment thereto furnished to the Underwriters will be identical to the electronically transmitted copies thereof filed with the Commission pursuant to ▇▇▇▇▇, except to the extent permitted by Regulation S-T.

(d) Delivery of Prospectuses. The Company has delivered to each Underwriter, without charge, as many copies of each preliminary prospectus as such Underwriter reasonably requested, and the Company hereby consents to the use of such copies for purposes permitted by the 1933 Act. The Company will furnish to each Underwriter, without charge, during the period when the Prospectus is required to be delivered under the 1933 Act, such number of copies of the Prospectus (as amended or supplemented) as such Underwriter may reasonably request. The Prospectus and any amendments or supplements thereto furnished to the Underwriters will be identical to the electronically transmitted copies thereof filed with the Commission pursuant to ▇▇▇▇▇, except to the extent permitted by Regulation S-T.

(e) Continued Compliance with Securities Laws. The Company will comply with the 1933 Act and the 1933 Act Regulations so as to permit the completion of the distribution of the Securities as contemplated in this Agreement and in the Prospectus. If at any time when a prospectus is required by the 1933 Act to be delivered in connection with sales of the Securities, any event shall occur or condition shall exist as a result of which it is necessary, in the opinion of counsel for the Underwriters or for the Company, to amend the Registration Statement or amend or supplement the Prospectus in order that the Prospectus will not include any untrue statements of a material fact or omit to state a material fact necessary in order to make the statements therein not misleading in the light of the circumstances existing at the time it is delivered to a purchaser, or if it shall be necessary, in the opinion of such counsel, at any such time to amend the Registration Statement or amend or supplement the Prospectus in order to comply with the requirements of the 1933 Act or the 1933 Act Regulations, the Company will promptly prepare and file with the Commission, subject to Section 3(b), such amendment or supplement as may be necessary to correct such statement or omission or to make the Registration Statement or the Prospectus comply with such requirements, and the Company will furnish to the Underwriters such number of copies of such amendment or supplement as the Underwriters may reasonably request.

(f) Blue Sky Qualifications. The Company will use its best efforts, in cooperation with the Underwriters, to qualify the Securities for offering and sale under the applicable securities laws of such states and other jurisdictions (domestic or foreign) as the Representatives may designate and to maintain such qualifications in effect for a period of not less than one year from the later of the effective date of the Registration Statement and any Rule 462(b) Registration Statement; provided, however, that the Company shall not be obligated to file any general consent to service of process or to qualify as a foreign corporation or as a dealer in securities in any jurisdiction in which it is not so qualified or to subject itself to taxation in respect of doing business in any jurisdiction in which it is not otherwise so subject.

(g) Rule 158. The Company will timely file such reports pursuant to the Securities Exchange Act of 1934 (the “1934 Act”) as are necessary in order to make generally available to its securityholders as soon as practicable an earnings statement for the purposes of, and to provide the benefits contemplated by, the last paragraph of Section 11(a) of the 1933 Act.

(h) Use of Proceeds. The Company will use the net proceeds received by it from the sale of the Securities in the manner specified in the Prospectus under “Use of Proceeds”.

(i) Listing. The Company will use its best efforts to effect and maintain the quotation of the Securities on the Nasdaq National Market.

(j) Restriction on Sale of Securities. During a period of 180 days from the date of the Prospectus, the Company will not, without the prior written consent of ▇▇▇▇▇▇▇ ▇▇▇▇▇, (i) directly or

indirectly, offer, pledge, sell, contract to sell, sell any option or contract to purchase, purchase any option or contract to sell, grant any option, right or warrant to purchase or otherwise transfer or dispose of any share of Common Stock or any securities convertible into or exercisable or exchangeable for Common Stock or file any registration statement under the 1933 Act with respect to any of the foregoing or (ii) enter into any swap or any other agreement or any transaction that transfers, in whole or in part, directly or indirectly, the economic consequence of ownership of the Common Stock, whether any such swap or transaction described in clause (i) or (ii) above is to be settled by delivery of Common Stock or such other securities, in cash or otherwise. The foregoing sentence shall not apply to (A) the Securities to be sold hereunder, (B) any shares of Common Stock issued by the Company upon the exercise of an option, warrant or convertible note outstanding on the date hereof and described in the Prospectus, (C) any shares of Common Stock issued or options to purchase Common Stock granted pursuant to existing employee benefit plans of the Company described in the Prospectus, (D) any shares of Common Stock issued pursuant to any non-employee director stock plan described in the Prospectus, or (E) any shares of Common Stock issued by the Company upon the exercise of the warrant issued to Cirrus Logic as described in the Prospectus. The Company agrees not to, without the prior written consent of ▇▇▇▇▇▇▇ ▇▇▇▇▇, release any stockholder or optionholder from any agreement with the Company, whether by contract or by law, whereby such person or entity has agreed not to sell or otherwise transfer or dispose of any Common Stock (or other securities) of the Company for a period of up to one hundred eighty 180 days following the commencement of the public offering of the Common Stock by the Underwriters or otherwise.

(k) Reporting Requirements. The Company, during the period when the Prospectus is required to be delivered under the 1933 Act, will file all documents required to be filed with the Commission pursuant to the 1934 Act within the time periods required by the 1934 Act and the rules and regulations of the Commission thereunder.

(l) Compliance with Rule 463. The Company will include such information in its periodic reports filed with the Commission as may be required pursuant to Rule 463 of the 1933 Act Regulations.

SECTION 4. Payment of Expenses.

(a) Expenses. The Company will pay all expenses incident to the performance of its obligations under this Agreement, including (i) the preparation, printing and filing of the Registration Statement (including financial statements and exhibits) as originally filed and of each amendment thereto, (ii) the preparation, printing and delivery to the Underwriters of this Agreement, any Agreement among Underwriters and such other documents as may be required in connection with the offering, purchase, sale, issuance or delivery of the Securities, (iii) the preparation, issuance and delivery of the certificates for the Securities to the Underwriters, including any stock or other transfer taxes and any stamp or other duties payable upon the sale, issuance or delivery of the Securities to the Underwriters, (iv) the fees and disbursements of the Company’s counsel, accountants and other advisors, (v) the qualification of the Securities under securities laws in accordance with the provisions of Section 3(f) hereof, including filing fees and the reasonable fees and disbursements of counsel for the Underwriters in connection therewith and in connection with the preparation of the Blue Sky Survey and any supplement thereto, (vi) the printing and delivery to the Underwriters of copies of each preliminary prospectus and of the Prospectus and any amendments or supplements thereto, (vii) the preparation, printing and delivery to the Underwriters of copies of the Blue Sky Survey and any supplement thereto, (viii) the fees and expenses of any transfer agent or registrar for the Securities, (ix) the costs and expenses of the Company relating to investor presentations on any “road show” undertaken in connection with the marketing of the Securities, including without limitation, expenses associated with the production of road show slides and graphics, fees and expenses of any consultants engaged in connection with the road show presentations, travel and lodging expenses of the representatives and officers of the Company and any such consultants, and the

cost of aircraft and other transportation chartered in connection with the road show and (x) the filing fees incident to, and the reasonable fees and disbursements of counsel to the Underwriters in connection with, the review by the National Association of Securities Dealers, Inc. (the “NASD”) of the terms of the sale of the Securities and (xi) the fees and expenses incurred in connection with the inclusion of the Securities in the Nasdaq National Market. Except as otherwise set forth herein, the Underwriters shall be responsible for all other expenses incurred by them including the fees and expenses of their counsel.

(b) Expenses of the Selling Stockholders. The Selling Stockholders, severally and not jointly, will pay all expenses incident to the performance of their respective obligations under, and the consummation of the transactions contemplated by this Agreement, including (i) any stamp duties, capital duties and stock transfer taxes, if any, payable upon the sale of the Securities to the Underwriters, and their transfer between the Underwriters pursuant to an agreement between such Underwriters, and (ii) the fees and disbursements of their respective counsel and other advisors.

(c) Termination of Agreement. If this Agreement is terminated by the Representatives in accordance with the provisions of Section 5, Section 9(a)(i) or Section 11 hereof, the Company and the Selling Stockholders shall reimburse the Underwriters for all of their out-of-pocket expenses, including the reasonable fees and disbursements of counsel for the Underwriters.

(d) Allocation of Expenses. The provisions of this Section 4 shall not affect any agreement that the Company and the Selling Stockholders may make for the sharing of such costs and expenses (it being expressly acknowledged, understood and agreed by the Company and the Selling Stockholders that the Company will bear and pay all expenses incurred by the Selling Stockholders in connection with the sale of their Securities to the Underwriters hereunder; however, the Company will not be responsible for attorneys fees of the Selling Stockholders, except that the Company will pay the reasonable fees and disbursements of ▇▇▇▇▇▇▇▇ & ▇▇▇▇▇▇▇▇ LLP, as special counsel to the Selling Stockholders). Notwithstanding anything to the contrary herein, the Company will not be responsible for underwriting discounts and commission on the Securities sold by the Selling Stockholders hereunder.

SECTION 5. Conditions of Underwriters’ Obligations. The obligations of the several Underwriters hereunder are subject to the accuracy of the representations and warranties of the Company and the Selling Stockholders contained in Section 1 hereof or in certificates of any officer of the Company or on behalf of any Selling Stockholder delivered pursuant to the provisions hereof, to the performance by the Company of its covenants and other obligations hereunder, and to the following further conditions:

(a) Effectiveness of Registration Statement. The Registration Statement, including any Rule 462(b) Registration Statement, has become effective and at Closing Time no stop order suspending the effectiveness of the Registration Statement shall have been issued under the 1933 Act or proceedings therefor initiated or threatened by the Commission, and any request on the part of the Commission for additional information shall have been complied with to the reasonable satisfaction of counsel to the Underwriters. A prospectus containing the Rule 430A Information shall have been filed with the Commission in accordance with Rule 424(b) (or a post-effective amendment providing such information shall have been filed and declared effective in accordance with the requirements of Rule 430A).

(b) Opinion of Counsel for Company. At Closing Time, the Representatives shall have received the favorable opinion, dated as of Closing Time, of ▇▇▇▇ ▇▇▇▇ ▇▇▇▇ & Freidenrich, LLP, counsel for the Company, in form and substance satisfactory to counsel for the Underwriters, together with signed or reproduced copies of such letter for each of the other Underwriters to the effect set forth in Exhibit A hereto and to such further effect as counsel to the Underwriters may reasonably request as a result of matters occurring after the date hereof and prior to the delivery of such opinion.

(c) Opinion of Counsel for the Selling Stockholders. At Closing Time, the Representatives shall have received the favorable opinion, dated as of Closing Time, of ▇▇▇▇▇▇▇▇ & ▇▇▇▇▇▇▇▇ LLP, special counsel for the Selling Stockholders, in form and substance satisfactory to counsel for the Underwriters, together with signed or reproduced copies of such letter for each of the other Underwriters to the effect set forth in Exhibit B hereto and to such further effect as counsel to the Underwriters may reasonably request.

(d) Opinion of Counsel for Underwriters. At Closing Time, the Representatives shall have received the favorable opinion, dated as of Closing Time, of ▇▇▇▇▇▇ ▇▇▇▇▇▇▇ ▇▇▇▇▇▇▇▇ & ▇▇▇▇▇▇, Professional Corporation, counsel for the Underwriters, together with signed or reproduced copies of such letter for each of the other Underwriters with respect to the matters set forth in clauses (i), (ii), (v), (vi) (solely as to preemptive or other similar rights arising by operation of law or under the charter or by-laws of the Company), (viii) through (x), inclusive, (xi), (xiii) (solely as to the information in the Prospectus under “Description of Capital Stock—Common Stock”) and the penultimate paragraph of Exhibit A hereto. In giving such opinion such counsel may rely, as to all matters governed by the laws of jurisdictions other than the law of the State of New York, the federal law of the United States and the General Corporation Law of the State of Delaware, upon the opinions of counsel satisfactory to the Representatives. Such counsel may also state that, insofar as such opinion involves factual matters, they have relied, to the extent they deem proper, upon certificates of officers of the Company and certificates of public officials.

(e) Officers’ Certificate. At Closing Time, there shall not have been, since the date hereof or since the respective dates as of which information is given in the Prospectus, any material adverse change in the condition, financial or otherwise, or in the earnings, business affairs or business prospects of the Company, whether or not arising in the ordinary course of business, and the Representatives shall have received a certificate of the Chief Executive Officer or President of the Company and of the Chief Financial Officer of the Company, dated as of Closing Time, to the effect that (i) there has been no such material adverse change, (ii) the representations and warranties in Section 1(a) hereof are true and correct with the same force and effect as though expressly made at and as of Closing Time, (iii) the Company has complied with all agreements and satisfied all conditions on its part to be performed or satisfied at or prior to Closing Time, and (iv) no stop order suspending the effectiveness of the Registration Statement has been issued and no proceedings for that purpose have been instituted or are pending or, to their knowledge, contemplated by the Commission.

(f) Certificate of Selling Stockholders. At Closing Time, the Representatives shall have received a certificate of an Attorney-in-Fact on behalf of each Selling Stockholder, dated as of Closing Time, to the effect that (i) the representations and warranties of such Selling Stockholder contained in Section 1(b) hereof are true and correct in all respects with the same force and effect as though expressly made at and as of Closing Time and (ii) such Selling Stockholder has complied in all material respects with all agreements and all conditions on its part to be performed under this Agreement at or prior to Closing Time.

(g) Accountant’s Comfort Letter. At the time of the execution of this Agreement, the Representatives shall have received from PricewaterhouseCoopers, LLP a letter dated such date, in form and substance satisfactory to the Representatives, together with signed or reproduced copies of such letter for each of the other Underwriters containing statements and information of the type ordinarily included in accountants’ “comfort letters” to underwriters with respect to the financial statements and certain financial information contained in the Registration Statement and the Prospectus.

(h) Bring-down Comfort Letter. At Closing Time, the Representatives shall have received from PricewaterhouseCoopers, LLP a letter, dated as of Closing Time, to the effect that they reaffirm the

statements made in the letter furnished pursuant to subsection (e) of this Section, except that the specified date referred to shall be a date not more than three business days prior to Closing Time.

(i) Approval of Listing. At Closing Time, the Securities shall have been approved for inclusion in the Nasdaq National Market, subject only to official notice of issuance.

(j) No Objection. The NASD has confirmed that it has not raised any objection with respect to the fairness and reasonableness of the underwriting terms and arrangements.

(k) Lock-up Agreements. At the date of this Agreement, the Representatives shall have received an agreement substantially in the form of Exhibit C hereto signed by the persons listed on Schedule D hereto.

(l) Conditions to Purchase of Option Securities. In the event that the Underwriters exercise their option provided in Section 2(b) hereof to purchase all or any portion of the Option Securities, the representations and warranties of the Company and the Selling Stockholders contained herein and the statements in any certificates furnished by the Company and the Selling Stockholders hereunder shall be true and correct as of each Date of Delivery and, at the relevant Date of Delivery, the Representatives shall have received:

(i) Officers’ Certificate. A certificate, dated such Date of Delivery, of the Chief Executive Officer or President of the Company and of the Chief Financial Officer of the Company confirming that the certificate delivered at the Closing Time pursuant to Section 5(d) hereof remains true and correct as of such Date of Delivery.

(ii) Certificate of Selling Stockholders. A certificate, dated such Date of Delivery, of an Attorney-in-Fact on behalf of each Selling Stockholder confirming that the certificate delivered at Closing Time pursuant to Section 5(f) remains true and correct as of such Date of Delivery.

(iii) Opinion of Counsel for Company. The favorable opinion of ▇▇▇▇ ▇▇▇▇ ▇▇▇▇ & Freidenrich, LLP, counsel for the Company, in form and substance satisfactory to counsel for the Underwriters, dated such Date of Delivery, relating to the Option Securities to be purchased on such Date of Delivery and otherwise to the same effect as the opinion required by Section 5(b) hereof.

(iv) Opinion of Counsel for the Selling Stockholders. The favorable opinion of ▇▇▇▇▇▇▇▇ & ▇▇▇▇▇▇▇▇ LLP, counsel for the Selling Stockholders, in form and substance satisfactory to counsel for the Underwriters, dated such Date of Delivery, relating to the Option Securities to be purchased on such Date of Delivery and otherwise to the same effect as the opinion required by Section 5(c) hereof.

(v) Opinion of Counsel for Underwriters. The favorable opinion of ▇▇▇▇▇▇ ▇▇▇▇▇▇▇ ▇▇▇▇▇▇▇▇ & ▇▇▇▇▇▇, Professional Corporation, counsel for the Underwriters, dated such Date of Delivery, relating to the Option Securities to be purchased on such Date of Delivery and otherwise to the same effect as the opinion required by Section 5(c) hereof.

(vi) Bring-down Comfort Letter. A letter from PricewaterhouseCoopers, LLP, in form and substance satisfactory to the Representatives and dated such Date of Delivery, substantially in the same form and substance as the letter furnished to the Representatives

pursuant to Section 5(f) hereof, except that the “specified date” in the letter furnished pursuant to this paragraph shall be a date not more than five days prior to such Date of Delivery.

(m) Additional Documents. At Closing Time and at each Date of Delivery, counsel for the Underwriters shall have been furnished with such documents and opinions as they may require for the purpose of enabling them to pass upon the issuance and sale of the Securities as herein contemplated, or in order to evidence the accuracy of any of the representations or warranties, or the fulfillment of any of the conditions, herein contained; and all proceedings taken by the Company and the Selling Stockholders in connection with the issuance and sale of the Securities as herein contemplated shall be satisfactory in form and substance to the Representatives and counsel for the Underwriters.

(n) Termination of Agreement. If any condition specified in this Section shall not have been fulfilled when and as required to be fulfilled, this Agreement, or, in the case of any condition to the purchase of Option Securities, on a Date of Delivery which is after the Closing Time, the obligations of the several Underwriters to purchase the relevant Option Securities, may be terminated by the Representatives by notice provided to the Company and ▇▇▇▇▇▇▇▇ & ▇▇▇▇▇▇▇▇ LLP, as special counsel to the Selling Stockholders, at any time at or prior to Closing Time or such Date of Delivery, as the case may be, and such termination shall be without liability of any party to any other party except as provided in Section 4 and except that Sections 1, 6, 7 and 8 shall survive any such termination and remain in full force and effect.

SECTION 6. Indemnification.

(a) Indemnification of Underwriters.

(i) The Company agrees to indemnify and hold harmless each Underwriter, its affiliates, as such term is defined in Rule 501(b) under the 1933 Act (each, an “Affiliate”), its selling agents and each person, if any, who controls any Underwriter within the meaning of Section 15 of the 1933 Act or Section 20 of the 1934 Act as follows:

(1) against any and all loss, liability, claim, damage and reasonable expense whatsoever, as incurred, arising out of any untrue statement or alleged untrue statement of a material fact contained in the Registration Statement (or any amendment thereto), including the Rule 430A Information or the omission or alleged omission therefrom of a material fact required to be stated therein or necessary to make the statements therein not misleading or arising out of any untrue statement or alleged untrue statement of a material fact included in any preliminary prospectus or the Prospectus (or any amendment or supplement thereto), or the omission or alleged omission therefrom of a material fact necessary in order to make the statements therein, in the light of the circumstances under which they were made, not misleading;

(2) against any and all loss, liability, claim, damage and reasonable expense whatsoever, as incurred, to the extent of the aggregate amount paid in settlement of any litigation, or any investigation or proceeding by any governmental agency or body, commenced or threatened, or of any claim whatsoever based upon any such untrue statement or omission, or any such alleged untrue statement or omission; provided that (subject to Section 6(d) below) any such settlement is effected with the written consent of the Company;

(3) against any and all expense whatsoever, as reasonably incurred (including the fees and disbursements of counsel chosen by ▇▇▇▇▇▇▇ ▇▇▇▇▇), in

investigating, preparing or defending against any litigation, or any investigation or proceeding by any governmental agency or body, commenced or threatened, or any claim whatsoever based upon any such untrue statement or omission, or any such alleged untrue statement or omission, to the extent that any such expense is not paid under (1) or (2) above;

provided, however, that this indemnity agreement shall not apply to any loss, liability, claim, damage or expense to the extent arising out of any untrue statement or omission or alleged untrue statement or omission made in reliance upon and in conformity with written information furnished to the Company by any Underwriter through ▇▇▇▇▇▇▇ ▇▇▇▇▇ expressly for use in the Registration Statement (or any amendment thereto), including the Rule 430A Information or any preliminary prospectus or the Prospectus (or any amendment or supplement thereto); and providedfurther that the Company will not be liable to any Underwriter with respect to any Prospectus to the extent that the Company shall sustain the burden of proving that any such loss, liability, claim, damage or expense resulted from the fact that such Underwriter, in contravention of a requirement of this Agreement or applicable law, sold Securities to a person to whom such Underwriter failed to send or give, at or prior to the Closing Date, a copy of the Final Prospectus, as then amended or supplemented if: (i) the Company has previously furnished copies thereof (sufficiently in advance of the Closing Date to allow for distribution by the Closing Date) to the Underwriter and the loss, liability, claim, damage or expense of such Underwriter resulted from an untrue statement or omission of a material fact contained in or omitted from the Preliminary Prospectus which was corrected in the Final Prospectus as, if applicable, amended or supplemented prior to the Closing Date and such Final Prospectus was required by law to be delivered at or prior to the written confirmation of sale to such person and (ii) such failure to give or send such Final Prospectus by the Closing Date to the party or parties asserting such loss, liability, claim, damage or expense would have constituted the sole defense to the claim asserted by such person.

(ii) Each Selling Stockholder, severally and not jointly, agrees to indemnify and hold harmless each Underwriter, its Affiliates and selling agents and each person, if any, who controls any Underwriter within the meaning of Section 15 of the 1933 Act or Section 20 of the 1934 Act to the extent and in the manner set forth in clauses (a)(i)(1), (2) and (3) above, but only with respect to information relating to such Selling Stockholder furnished in writing by or on behalf of such Selling Stockholder expressly for use in the Registration Statement, any preliminary prospectus, the Prospectus or any amendments or supplements thereto. The Underwriters acknowledge and agree that the statements relating to each Selling Stockholder under the caption “Principal and Selling Stockholders” in the Prospectus constitute the only information furnished in writing by or on behalf of such Selling Stockholder expressly for use in the Registration Statement, any preliminary prospectus, the Prospectus or any amendments or supplements thereto.

(b) Indemnification of Company, Directors and Officers and Selling Stockholders. Each Underwriter severally agrees to indemnify and hold harmless the Company, its directors, each of its officers who signed the Registration Statement, and each person, if any, who controls the Company within the meaning of Section 15 of the 1933 Act or Section 20 of the 1934 Act, and each Selling Stockholder and each person, if any, who controls any Selling Stockholder within the meaning of Section 15 of the 1933 Act or Section 20 of the 1934 Act against any and all loss, liability, claim, damage and expense described in the indemnity contained in subsection (a)(i) of this Section, as incurred, but only with respect to untrue statements or omissions, or alleged untrue statements or omissions, made in the Registration Statement (or any amendment thereto), including the Rule 430A Information or any preliminary prospectus or the Prospectus (or any amendment or supplement thereto) in reliance upon and in conformity with written information furnished to the Company by such Underwriter through ▇▇▇▇▇▇▇ ▇▇▇▇▇ expressly for use in the Registration Statement (or any amendment thereto) or such preliminary prospectus or the Prospectus (or any amendment or supplement thereto).

(c) Actions against Parties; Notification. Each indemnified party shall give notice as promptly as reasonably practicable to each indemnifying party of any action commenced against it in respect of which indemnity may be sought hereunder, but failure to so notify an indemnifying party, and any delay in such notification, shall not relieve such indemnifying party from any liability hereunder to the extent it is not materially prejudiced as a result thereof and in any event shall not relieve it from any liability which it may have otherwise than on account of this indemnity agreement. In the case of parties indemnified pursuant to Section 6(a) above, counsel to the indemnified parties shall be selected by ▇▇▇▇▇▇▇ ▇▇▇▇▇, and, in the case of parties indemnified pursuant to Section 6(b) above, counsel to the indemnified parties shall be selected by the Company. An indemnifying party may participate at its own expense in the defense of any such action; provided, however, that counsel to the indemnifying party shall not (except with the consent of the indemnified party) also be counsel to the indemnified party. In no event shall the indemnifying parties be liable for fees and expenses of more than one counsel (in addition to any local counsel) separate from their own counsel for all indemnified parties in connection with any one action or separate but similar or related actions in the same jurisdiction arising out of the same general allegations or circumstances. No indemnifying party shall, without the prior written consent of the indemnified parties, settle or compromise or consent to the entry of any judgment with respect to any litigation, or any investigation or proceeding by any governmental agency or body, commenced or threatened, or any claim whatsoever in respect of which indemnification or contribution could be sought under this Section 6 or Section 7 hereof (whether or not the indemnified parties are actual or potential parties thereto), unless such settlement, compromise or consent (i) includes an unconditional release of each indemnified party from all liability arising out of such litigation, investigation, proceeding or claim and (ii) does not include a statement as to or an admission of fault, culpability or a failure to act by or on behalf of any indemnified party.

(d) Settlement without Consent if Failure to Reimburse. If at any time an indemnified party shall have requested an indemnifying party to reimburse the indemnified party for reasonable fees and expenses of counsel with respect to a claim in respect of which indemnification or contribution could be sought under this Section 6 or Section 7 hereof, such indemnifying party agrees that it shall be liable for any settlement of the nature contemplated by Section 6(a)(i)(2) effected without its written consent if (i) such settlement is entered into more than 45 days after receipt by such indemnifying party of the aforesaid request, (ii) such indemnifying party shall have received notice of the terms of such settlement at least 30 days prior to such settlement being entered into and (iii) such indemnifying party shall not have reimbursed such indemnified party in accordance with such request prior to the date of such settlement.

(e) Other Agreements with Respect to Indemnification. The provisions of this Section shall not affect any agreement among the Company and the Selling Stockholders with respect to indemnification, including the indemnification provisions in that Second Amended and Restated Investors’ Rights Agreement dated August 15, 2000, by and among the Company, Selling Stockholders and certain other parties, as amended.

(f) Limitation of Liability. The aggregate liability of each Selling Stockholder under this Agreement shall not exceed the net proceeds received by such Selling Stockholder in the offering after deduction of the underwriting discount and commissions.

SECTION 7. Contribution. If the indemnification provided for in Section 6 hereof is for any reason unavailable to or insufficient to hold harmless an indemnified party in respect of any losses, liabilities, claims, damages or expenses referred to therein, then each indemnifying party shall contribute to the aggregate amount of such losses, liabilities, claims, damages and expenses incurred by such indemnified party, as incurred, (i) in such proportion as is appropriate to reflect the relative benefits received by the Company and the Selling Stockholders on the one hand and the Underwriters on the other hand from the offering of the Securities pursuant to this Agreement or (ii) if the allocation provided by

clause (i) is not permitted by applicable law, in such proportion as is appropriate to reflect not only the relative benefits referred to in clause (i) above but also the relative fault of the Company and the Selling Stockholders on the one hand and of the Underwriters on the other hand in connection with the statements or omissions which resulted in such losses, liabilities, claims, damages or expenses, as well as any other relevant equitable considerations.

The relative benefits received by the Company and the Selling Stockholders on the one hand and the Underwriters on the other hand in connection with the offering of the Securities pursuant to this Agreement shall be deemed to be in the same respective proportions as the total net proceeds from the offering of the Securities pursuant to this Agreement (before deducting expenses) received by the Company and the Selling Stockholders and the total underwriting discount received by the Underwriters, in each case as set forth on the cover of the Prospectus, bear to the aggregate initial public offering price of the Securities as set forth on the cover of the Prospectus.

The relative fault of the Company and the Selling Stockholders on the one hand and the Underwriters on the other hand shall be determined by reference to, among other things, whether any such untrue or alleged untrue statement of a material fact or omission or alleged omission to state a material fact relates to information supplied by the Company or the Selling Stockholders or by the Underwriters and the parties’ relative intent, knowledge, access to information and opportunity to correct or prevent such statement or omission. The Underwriters acknowledge and agree that the statements relating to each Selling Stockholder under the caption “Principal and Selling Stockholders” in the Prospectus constitute the only information furnished in writing by or on behalf of such Selling Stockholder expressly for use in the Registration Statement, any preliminary prospectus, the Prospectus or any amendments or supplements thereto. The Company and each of the Selling Stockholders acknowledge and agree that the only information provided by the Underwriters is that written information furnished to the Company by such Underwriter through ▇▇▇▇▇▇▇ ▇▇▇▇▇ expressly for use in the Registration Statement (or any amendment thereto) or such preliminary prospectus or the Prospectus (or any amendment or supplement thereto).

The Company, the Selling Stockholders and the Underwriters agree that it would not be just and equitable if contribution pursuant to this Section 7 were determined by pro rata allocation (even if the Underwriters were treated as one entity for such purpose) or by any other method of allocation which does not take account of the equitable considerations referred to above in this Section 7. The aggregate amount of losses, liabilities, claims, damages and expenses incurred by an indemnified party and referred to above in this Section 7 shall be deemed to include any legal or other expenses reasonably incurred by such indemnified party in investigating, preparing or defending against any litigation, or any investigation or proceeding by any governmental agency or body, commenced or threatened, or any claim whatsoever based upon any such untrue or alleged untrue statement or omission or alleged omission.

Notwithstanding the provisions of this Section 7, (i) no Underwriter shall be required to contribute any amount in excess of the amount by which the total price at which the Securities underwritten by it and distributed to the public were offered to the public exceeds the amount of any damages which such Underwriter has otherwise been required to pay by reason of any such untrue or alleged untrue statement or omission or alleged omission, and (ii) no Selling Stockholder shall be required to contribute any amount in excess of the net proceeds received by such Selling Stockholders from the sale of its Securities pursuant to this Agreement.

No person guilty of fraudulent misrepresentation (within the meaning of Section 11(f) of the ▇▇▇▇ ▇▇▇) shall be entitled to contribution from any person who was not guilty of such fraudulent misrepresentation.

For purposes of this Section 7, each person, if any, who controls an Underwriter within the meaning of Section 15 of the 1933 Act or Section 20 of the 1934 Act and each Underwriter’s Affiliates and selling agents shall have the same rights to contribution as such Underwriter, and each director of the Company, each officer of the Company who signed the Registration Statement, and each person, if any, who controls the Company or any Selling Stockholder within the meaning of Section 15 of the 1933 Act or Section 20 of the 1934 Act shall have the same rights to contribution as the Company or such Selling Stockholders, as the case may be. The Underwriters’ respective obligations to contribute pursuant to this Section 7 are several in proportion to the number of Initial Securities set forth opposite their respective names in Schedule A hereto and not joint. The Selling Stockholders’ respective obligations to contribute pursuant to this Section 7 are several in proportion to the number of Securities set forth opposite their respective names in Schedule B hereto and not joint.

The provisions of this Section 7 shall not affect any agreement among the Company and the Selling Stockholders with respect to contribution.

SECTION 8. Representations, Warranties and Agreements to Survive. All representations, warranties and agreements contained in this Agreement or in certificates of officers of the Company or the Selling Stockholders submitted pursuant hereto, shall remain operative and in full force and effect regardless of (i) any investigation made by or on behalf of any Underwriter or its Affiliates or selling agents, any person controlling any Underwriter, its officers or directors, any person controlling the Company or any person controlling any Selling Stockholder and (ii) delivery of and payment for the Securities.

SECTION 9. Termination of Agreement.

(a) Termination; General. The Representatives may terminate this Agreement, by notice to the Company and ▇▇▇▇▇▇▇▇ & ▇▇▇▇▇▇▇▇ LLP, as special counsel to the Selling Stockholders, at any time at or prior to Closing Time (i) if there has been, since the time of execution of this Agreement or since the respective dates as of which information is given in the Prospectus, any material adverse change in the condition, financial or otherwise, or in the earnings, business affairs or business prospects of the Company, whether or not arising in the ordinary course of business, or (ii) if there has occurred any material adverse change in the financial markets in the United States or the international financial markets, any outbreak of hostilities or escalation thereof or other calamity or crisis or any change or development involving a prospective change in national or international political, financial or economic conditions, in each case the effect of which is such as to make it, in the judgment of the Representatives, impracticable or inadvisable to market the Securities or to enforce contracts for the sale of the Securities, or (iii) if trading in any securities of the Company has been suspended or materially limited by the Commission or the Nasdaq National Market, or if trading generally on the American Stock Exchange or the New York Stock Exchange or in the Nasdaq National Market has been suspended or materially limited, or minimum or maximum prices for trading have been fixed, or maximum ranges for prices have been required, by any of said exchanges or by such system or by order of the Commission, the NASD or any other governmental authority, or (iv) a material disruption has occurred in commercial banking or securities settlement or clearance services in the United States, or (v) if a banking moratorium has been declared by either Federal, New York, Delaware or Texas authorities.

(b) Liabilities. If this Agreement is terminated pursuant to this Section, such termination shall be without liability of any party to any other party except as provided in Section 4 hereof, and provided further that Sections 1, 6, 7 and 8 shall survive such termination and remain in full force and effect.

SECTION 10. Default by One or More of the Underwriters. If one or more of the Underwriters shall fail at Closing Time or a Date of Delivery to purchase the Securities which it or they are obligated to

purchase under this Agreement (the “Defaulted Securities”), the Representatives shall have the right, within 24 hours thereafter, to make arrangements for one or more of the non-defaulting Underwriters, or any other underwriters, to purchase all, but not less than all, of the Defaulted Securities in such amounts as may be agreed upon and upon the terms herein set forth; if, however, the Representatives shall not have completed such arrangements within such 24-hour period, then:

(i) if the number of Defaulted Securities does not exceed 10% of the number of Securities to be purchased on such date, each of the non-defaulting Underwriters shall be obligated, severally and not jointly, to purchase the full amount thereof in the proportions that their respective underwriting obligations hereunder bear to the underwriting obligations of all non-defaulting Underwriters, or

(ii) if the number of Defaulted Securities exceeds 10% of the number of Securities to be purchased on such date, this Agreement or, with respect to any Date of Delivery which occurs after the Closing Time, the obligation of the Underwriters to purchase and of the Company to sell the Option Securities to be purchased and sold on such Date of Delivery shall terminate without liability on the part of any non-defaulting Underwriter.

No action taken pursuant to this Section shall relieve any defaulting Underwriter from liability in respect of or arising from its default.

In the event of any such default which does not result in a termination of this Agreement or, in the case of a Date of Delivery which is after the Closing Time, which does not result in a termination of the obligation of the Underwriters to purchase and the Company to sell the relevant Option Securities, as the case may be, either the Representatives or the Company shall have the right to postpone Closing Time or the relevant Date of Delivery, as the case may be, for a period not exceeding seven days in order to effect any required changes in the Registration Statement or Prospectus or in any other documents or arrangements. As used herein, the term “Underwriter” includes any person substituted for an Underwriter under this Section 10.

SECTION 11. Default by one or more of the Selling Stockholders or the Company.

(a) If a Selling Stockholder shall fail at Closing Time or at a Date of Delivery to sell and deliver the number of Securities which such Selling Stockholder is obligated to sell hereunder, and the remaining Selling Stockholders do not exercise the right hereby granted to increase, pro rata or otherwise, the number of Securities to be sold by them hereunder to the total number to be sold by all Selling Stockholders as set forth in Schedule B hereto, then the Underwriters may, at option of the Representatives, by notice from the Representatives to the Company and ▇▇▇▇▇▇▇▇ & ▇▇▇▇▇▇▇▇ LLP, as special counsel to the Selling Stockholders, either (i) terminate this Agreement without any liability on the fault of any non-defaulting party except that the provisions of Sections 1, 4, 6, 7 and 8 shall remain in full force and effect or (ii) elect to purchase the Securities which the non-defaulting Selling Stockholders and the Company have agreed to sell hereunder. No action taken pursuant to this Section 11 shall relieve any Selling Stockholder so defaulting from liability, if any, in respect of or arising from such default.

In the event of a default by any Selling Stockholder as referred to in this Section 11, each of the Representatives, the Company and the non-defaulting Selling Stockholders shall have the right to postpone Closing Time or Date of Delivery for a period not exceeding seven days in order to effect any required change in the Registration Statement or Prospectus or in any other documents or arrangements.

(b) If the Company shall fail at Closing Time or at the Date of Delivery to sell the number of Securities that it is obligated to sell hereunder, then this Agreement shall terminate without any liability

on the part of any nondefaulting party; provided, however, that the provisions of Sections 1, 4, 6, 7 and 8 shall remain in full force and effect. No action taken pursuant to this Section shall relieve the Company from liability, if any, in respect of such default.

SECTION 12. Tax Disclosure. Notwithstanding any other provision of this Agreement, from the commencement of discussions with respect to the transactions contemplated hereby, the Company (and each employee, representative or other agent of the Company) may disclose to any and all persons, without limitation of any kind, the tax treatment and tax structure (as such terms are used in Sections 6011, 6111 and 6112 of the U.S. Code and the Treasury Regulations promulgated thereunder) of the transactions contemplated by this Agreement and all materials of any kind (including opinions or other tax analyses) that are provided relating to such tax treatment and tax structure.

SECTION 13. Notices. All notices and other communications hereunder shall be in writing and shall be deemed to have been duly given if mailed or transmitted by any standard form of telecommunication. Notices to the Underwriters shall be directed to the Representatives at ▇▇▇▇▇▇▇ ▇▇▇▇▇ & Co., ▇▇▇▇ ▇ ▇▇▇▇▇▇ ▇▇▇, ▇▇▇▇ ▇▇▇▇, ▇▇▇▇▇▇▇▇▇▇ ▇▇▇▇▇, attention ▇▇▇ ▇▇▇▇▇▇; notices to the Company shall be directed to it at ▇▇▇▇ ▇▇▇▇▇▇▇ ▇▇ ▇▇▇▇▇ ▇▇▇▇▇▇▇, ▇▇▇▇▇ ▇▇▇, ▇▇▇▇▇▇, ▇▇▇▇▇ ▇▇▇▇▇, attention of Chief Executive Officer; and notices to the Selling Stockholders shall be directed to ▇▇▇▇▇▇▇▇ & ▇▇▇▇▇▇▇▇ LLP, ▇▇▇ ▇▇▇▇ ▇▇▇▇▇ ▇▇▇▇▇▇, ▇▇▇▇▇ ▇▇▇▇, ▇▇▇ ▇▇▇▇▇▇▇, ▇▇▇▇▇▇▇▇▇▇ ▇▇▇▇▇, attention of ▇▇▇▇▇▇▇ ▇. ▇▇▇.

SECTION 14. Parties. This Agreement shall each inure to the benefit of and be binding upon the Underwriters and the Company and the Selling Stockholders and their respective successors. Nothing expressed or mentioned in this Agreement is intended or shall be construed to give any person, firm or corporation, other than the Underwriters, the Company and the Selling Stockholders and their respective successors and the controlling persons and officers and directors referred to in Sections 6 and 7 and their heirs and legal representatives, any legal or equitable right, remedy or claim under or in respect of this Agreement or any provision herein contained. This Agreement and all conditions and provisions hereof are intended to be for the sole and exclusive benefit of the Underwriters, the Company and the Selling Stockholders and their respective successors, and said controlling persons and officers and directors and their heirs and legal representatives, and for the benefit of no other person, firm or corporation. No purchaser of Securities from any Underwriter shall be deemed to be a successor by reason merely of such purchase.

SECTION 15. GOVERNING LAW. THIS AGREEMENT SHALL BE GOVERNED BY AND CONSTRUED IN ACCORDANCE WITH THE LAWS OF THE STATE OF NEW YORK.

SECTION 16. TIME. TIME SHALL BE OF THE ESSENCE OF THIS AGREEMENT. EXCEPT AS OTHERWISE SET FORTH HEREIN, SPECIFIED TIMES OF DAY REFER TO NEW YORK CITY TIME.

SECTION 17. Counterparts. This Agreement may be executed in any number of counterparts, each of which shall be deemed to be an original, but all such counterparts shall together constitute one and the same Agreement.

SECTION 18. Effect of Headings. The Section headings herein are for convenience only and shall not affect the construction hereof.

[Remainder of Page Intentionally Left Blank]

If the foregoing is in accordance with your understanding of our agreement, please sign and return to the Company and the Attorney-in-Fact for the Selling Stockholders a counterpart hereof, whereupon this instrument, along with all counterparts, will become a binding agreement among the Underwriters, the Company and the Selling Stockholders in accordance with its terms.

Very truly yours, SIGMATEL, INC.

By:
		▇▇▇ ▇▇▇▇▇▇▇▇, President and Chief Executive Officer

By:
		▇▇▇ ▇▇▇▇▇▇▇▇, As Attorney-in-Fact acting on behalf of each of the Selling Stockholders named in Schedule B hereto

CONFIRMED AND ACCEPTED,

as of the date first above written:

▇▇▇▇▇▇▇ ▇▇▇▇▇ & CO.

▇▇▇▇▇▇▇ LYNCH, PIERCE, ▇▇▇▇▇▇ & ▇▇▇▇▇

INCORPORATED

▇.▇. ▇▇▇▇▇▇ SECURITIES INC.

CIBC WORLD MARKETS CORP.

▇▇▇▇▇▇▇ & COMPANY, INC.

By:

▇▇▇▇▇▇▇ LYNCH, PIERCE, ▇▇▇▇▇▇ & ▇▇▇▇▇

INCORPORATED


By:
		Authorized Signatory

For themselves and as Representatives of the other Underwriters named in Schedule A hereto.

SCHEDULE A

Name of Underwriter		Number of Initial Securities
▇▇▇▇▇▇▇ Lynch, Pierce, ▇▇▇▇▇▇ & ▇▇▇▇▇ Incorporated
▇.▇. ▇▇▇▇▇▇ Securities Inc.
CIBC World Markets Corp
▇▇▇▇▇▇▇ & Company, Inc

Total		10,000,000

Sch A-1

SCHEDULE B

	Number of Initial Securities to be Sold	Maximum Number of Option Securities to Be Sold

SigmaTel, Inc.	7,000,000	395,239

Telesoft Partners IA, L.P.	1,331,215	543,349

Philips Semiconductors, Inc.	728,434	297,318

Hikari Tsushin, Inc.	347,039	141,648

Cirrus Logic, Inc.	284,059	115,941

Fermat Enterprises Ltd.	110,893	—

Silver Age International Limited	70,825	—

ALPS International Co., Ltd.	70,749	—

▇▇▇▇-▇▇▇▇ ▇▇▇	13,693	—

▇▇▇▇▇ and ▇▇▇▇▇▇▇ ▇▇▇▇▇▇	10,000	—

▇▇▇▇▇-Bin Chu	13,126	—

MoFo 2000, L.P.	11,186	4,565

▇▇▇▇▇▇▇ ▇▇▇	4,027	—

▇▇▇▇▇ ▇. ▇▇▇▇▇▇	3,618	1,477

▇▇▇▇▇▇▇ ▇▇▇	681	277

▇▇▇▇▇▇▇ ▇. ▇▇▇▇	455	186

Total	10,000,000	1,500,000

Sch B-1

SCHEDULE C

SIGMATEL, INC.

10,000,000 Shares of Common Stock

(Par Value $0.0001 Per Share)

1. The initial public offering price per share for the Securities, determined as provided in said Section 2, shall be $l.

2. The purchase price per share for the Securities to be paid by the several Underwriters shall be $l, being an amount equal to the initial public offering price set forth above less $l per share; provided that the purchase price per share for any Option Securities purchased upon the exercise of the overallotment option described in Section 2(b) shall be reduced by an amount per share equal to any dividends or distributions declared by the Company and payable on the Initial Securities but not payable on the Option Securities.

Sch C-1

[SCHEDULE D]

[List of persons and entities

subject to lock-up]

Sch D-1

Exhibit A

FORM OF OPINION OF COMPANY’S COUNSEL

TO BE DELIVERED PURSUANT TO

SECTION 5(b)

A-1

Exhibit B

FORM OF OPINION OF COUNSEL FOR THE SELLING STOCKHOLDERS

TO BE DELIVERED PURSUANT TO SECTION 5(c)

B-1

[Form of lock-up from directors, officers or other stockholders pursuant to Section 5(k)]

Exhibit C

June , 2003

▇▇▇▇▇▇▇ ▇▇▇▇▇ & CO.

▇▇▇▇▇▇▇ Lynch, Pierce, ▇▇▇▇▇▇ & ▇▇▇▇▇

Incorporated,

▇.▇. ▇▇▇▇▇▇ Securities, Inc.

▇▇▇▇▇▇▇ & Company, Inc.

CIBC World Markets Corp.

as Representatives of the several

Underwriters to be named in the

within-mentioned Purchase Agreement

▇/▇ ▇▇▇▇▇▇▇ ▇▇▇▇▇ & ▇▇.

▇▇▇▇▇▇▇

Lynch, Pierce, ▇▇▇▇▇▇ & ▇▇▇▇▇

Incorporated

▇ ▇▇▇▇▇ ▇▇▇▇▇▇▇▇▇ ▇▇▇▇▇▇

▇▇▇ ▇▇▇▇, ▇▇▇ ▇▇▇▇ ▇▇▇▇▇

Re:

Proposed Public Offering by SigmaTel, Inc.

Dear Sirs:

The undersigned, a stockholder, officer and/or director of SigmaTel, Inc., a Texas corporation (together with any successor corporation in a reincorporation, reorganization or other similar transaction undertaken by SigmaTel, Inc., the “Company”), understands that ▇▇▇▇▇▇▇ ▇▇▇▇▇ & Co., ▇▇▇▇▇▇▇ Lynch, Pierce, ▇▇▇▇▇▇ & ▇▇▇▇▇ Incorporated (“▇▇▇▇▇▇▇ ▇▇▇▇▇”), ▇.▇. ▇▇▇▇▇▇ Securities, Inc., ▇▇▇▇▇▇▇ & Company, Inc. and CIBC World Markets Corp. propose to enter into a Purchase Agreement (the “Purchase Agreement”) with the Company providing for the public offering of shares (the “Securities”) of the Company’s common stock, par value $0.005 per share (the “Common Stock”). In recognition of the benefit that such an offering will confer upon the undersigned as a stockholder, officer and/or director of the Company, and for other good and valuable consideration, the receipt and sufficiency of which are hereby acknowledged, the undersigned agrees with each underwriter to be named in the Purchase Agreement that, during a period of 180 days from the date of the Purchase Agreement, the undersigned will not, without the prior written consent of ▇▇▇▇▇▇▇ ▇▇▇▇▇, directly or indirectly, (i) offer, pledge, sell, contract to sell, sell any option or contract to purchase, purchase any option or contract to sell, grant any option, right or warrant for the sale of, or otherwise dispose of or transfer any shares of the Company’s Common Stock or any securities convertible into or exchangeable or exercisable for Common Stock, whether now owned or hereafter acquired by the undersigned or with respect to which the undersigned has or hereafter acquires the power of disposition, or file, or cause to be filed, any registration statement under the Securities Act of 1933, as amended, with respect to any of the foregoing (collectively, the “Lock-Up Securities”) or (ii) enter into any swap or any other agreement or any transaction that transfers, in whole or in part, directly or indirectly, the economic consequence of ownership of the Lock-Up Securities, whether any such swap or transaction is to be settled by delivery of Common Stock or other securities, in cash or otherwise.

C-1

Notwithstanding the foregoing, the undersigned may transfer the Lock-Up Securities without the prior written consent of ▇▇▇▇▇▇▇ ▇▇▇▇▇, (i) as a bona fide gift or gifts, provided that the donee or donees thereof agree to be bound in writing by the restriction set forth herein, or (ii) to any trust for the direct or indirect benefit of the undersigned or the immediate family of the undersigned, provided that the trustee of the trust agrees to be bound in writing by the restrictions set forth herein, and provided further that any such transfer shall not involve a disposition for value. For purposes of this lock-up agreement, “immediate family” shall mean any relationship by blood, marriage or adoption, not more remote than first cousin. The undersigned also agrees and consents to the entry of stop transfer instructions with the Company’s transfer agent and registrar against the transfer of the Lock-Up Securities except in compliance with the foregoing restrictions.

The undersigned hereby waives any rights the undersigned may have, pursuant to any registration rights agreement or otherwise, to include for resale in the proposed offering any securities of the Company held by the undersigned.

The undersigned hereby acknowledges that this Agreement is valid, binding and irrevocable notwithstanding any prior agreements relating to this matter and understands that this Agreement shall be binding upon the undersigned’s heirs, legal representatives, successors and assigns. The undersigned further acknowledges that the Company intends to undertake a reincorporation in the State of Delaware in connection with the proposed offering, and agrees that this Agreement shall continue in full force and effect with respect to any securities the undersigned acquires in any successor corporation in a reincorporation, reorganization or similar transaction undertaken by SigmaTel, Inc.

Very truly yours,

Signature:

Print Name:

C-2

SIGMATEL, INC. (Delaware corporation) 10,000,000 Shares of Common Stock PURCHASE AGREEMENT

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