THE EXECUTIVE NONQUALIFIED EXCESS PLANSM

Exhibit 10.11

ADOPTION AGREEMENT

THIS AGREEMENT is the adoption by Semtech Corporation (the “Employer”) of the Executive Nonqualified Excess Plan (“Plan”).

W I T N E S S E T H:

WHEREAS, the Employer desires to adopt the Plan as an unfunded, nonqualified deferred compensation plan; and

WHEREAS, the provisions of the Plan are intended to comply with the requirements of Section 409A of the Code and the regulations thereunder, and shall apply to amounts deferred after January 1, 2005, and to amounts deferred under the terms of any predecessor plan which are not earned and vested before January 1, 2005; and

WHEREAS, the Employer has been advised by Principal Life Insurance Company to obtain legal and tax advice from its professional advisors before adopting the Plan, and Principal Life Insurance Company disclaims all liability for the legal and tax consequences which result from the elections made by the Employer in this Adoption Agreement;

NOW, THEREFORE, the Employer hereby adopts the Plan in accordance with the terms and conditions set forth in this Adoption Agreement:

ARTICLE I

Terms used in this Adoption Agreement shall have the same meaning as in the Plan, unless some other meaning is expressly herein set forth. The Employer hereby represents and warrants that the Plan has been adopted by the Employer upon proper authorization and the Employer hereby elects to adopt the Plan for the benefit of its Participants as referred to in the Plan. By the execution of this Adoption Agreement, the Employer hereby agrees to be bound by the terms of the Plan.

ARTICLE II

The Employer hereby makes the following designations or elections for the purpose of the Plan:

2.6 Committee: The duties of the Committee set forth in the Plan shall be satisfied by:

2.7 Compensation: The “Compensation” of a Participant shall mean all of a Participant’s:

2.8 Crediting Date: The Deferred Compensation Account of a Participant shall be credited with the amount of any Participant Deferral to such account at the time designated below:

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2.12 Effective Date:

2.18 Normal Retirement Age: The Normal Retirement Age of a Participant shall be:

2.22 Participating Employer(s): As of the Effective Date, the following Participating Employer(s) are parties to the Plan:

2.24 Plan: The name of the Plan as applied to the Employer is Semtech Executive Compensation Plan.

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2.25 Plan Administrator: The Plan Administrator shall be:

2.27 Plan Year: The Plan Year shall end each year on the last day of the month of December.

2.35 Trust:

4.1 Participant Deferral Credits: Subject to the limitations in Section 4.1 of the Plan, a Participant may elect to have his Compensation (as selected in Section 2.7 of this Adoption Agreement) deferred within the annual limits below by the following percentage or amount as designated in writing to the Committee:

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4.2 Employer Credits: The Employer will make Employer Credits in the following manner:

5.3 Death of a Participant: If the Participant dies while in Service, the Employer shall pay a benefit to the Beneficiary in an amount equal to the vested balance in the Deferred Compensation Account of the Participant determined as of the date payments to the Beneficiary commence, plus:

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5.4 In-Service Distributions: In-service accounts are permitted under the Plan:

5.5 Education Distributions: Education accounts are permitted under the Plan:

5.6 Change in Control: Participant may elect to receive distributions under the Plan upon a Change in Control:

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6.1 Payment Options: Any benefit payable under the Plan upon a Qualifying Distribution Event may be made to the Participant or his Beneficiary (as applicable) in any of the following payment forms, as selected by the Participant in the Participant Deferral Agreement:

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6.2 De Minimis Amounts. Notwithstanding any payment election made by the Participant, the vested balance in the Deferred Compensation Account of the Participant will be distributed in a single lump sum payment if the payment accompanies the termination of the Participant’s entire interest in the Plan and the amount of such payment does not exceed $ 50,000.

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7. Vesting: An Active Participant shall be fully vested in the Employer Credits made to the Deferred Compensation Account upon the first to occur of the following events:

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14. Amendment and Termination of Plan: Notwithstanding any provision in this Adoption Agreement or the Plan to the contrary, Section      of the Plan shall be amended to read as provided in attached Exhibit     .

XX There are no amendments to the Plan.

17.9 Construction: The provisions of the Plan and Trust (if any) shall be construed and enforced according to the laws of the State of Delaware, except to the extent that such laws are superseded by ERISA and the applicable provisions of the Code.

IN WITNESS WHEREOF, this Agreement has been executed as of the day and year first above stated.

The Plan is adopted by the following Participating Employers:

NOTE: Execution of this Adoption Agreement creates a legal liability of the Employer with significant tax consequences to the Employer and Participants. The Employer should obtain legal and tax advice from its professional advisors before adopting the Plan. Principal Life Insurance Company disclaims all liability for the legal and tax consequences which result from the elections made by the Employer in this Adoption Agreement.

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