Semtech (SMTC) 10-Q 2005 Q3 Quarterly report

Exhibit 32.1

CERTIFICATION PURSUANT TO

18 USC 1350 AS ADOPTED PURSUANT TO

SECTION 906 OF THE SARBANES-OXLEY ACT OF 2002

In connection with the Quarterly Report of Semtech Corporation (the “Company”) on Form 10-Q for the period ended October 31, 2004 as filed with the Securities and Exchange Commission on the date hereof (the “Report”), I, Jason L. Carlson, Chief Executive Officer of the Company, hereby certify pursuant to 18 USC 1350, as adopted pursuant to Section 906 of the Sarbanes-Oxley Act of 2002, that:

1. the Report fully complies with the requirements of section 13(a) or 15(d) of the Securities Exchange Act of 1934; and

2. the information contained in the Report fairly presents, in all material respects, the financial condition and results of operations of the Company.

Date: December 10, 2004

/s/ Jason L. Carlson

Jason L. Carlson

Chief Executive Officer

A signed original of this written statement required by Section 906, or other document authenticating, acknowledging, or otherwise adopting the signature that appears in typed form within the electronic version of this written statement required by Section 906, has been provided to Semtech Corporation and will be retained by Semtech Corporation and furnished to the Securities and Exchange Commission or its staff upon request.

The information contained in this Exhibit 32.1 is being furnished and shall not be deemed “filed” for the purposes of Section 18 of the Securities Exchange Act of 1934, as amended, or otherwise subject to the liabilities of that section. The information in this Exhibit 32.1 shall not be incorporated by reference into any registration statement or other document pursuant to the Securities Exchange Act of 1934, as amended, or the Securities Act of 1933, as amended, except as shall be expressly set forth by specific reference to this Exhibit 32.1 in such filing

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