Semtech (SMTC) S-8 Registration of securities for employees

Exhibit 23.1

Consent of Independent Registered Public Accounting Firm

We consent to the incorporation by reference in the Registration Statement (Form S-8) pertaining to the Long-Term Stock Incentive Plan of Semtech Corporation of our reports dated April 10, 2007, with respect to the consolidated financial statements and financial statement schedule of Semtech Corporation included in its Annual Report (Form 10-K) for the year ended January 28, 2007, Semtech Corporation management’s assessment of the effectiveness of internal control over financial reporting, and the effectiveness of internal control over financial reporting of Semtech Corporation, filed with the Securities and Exchange Commission.

/s/ Ernst & Young LLP

Woodland Hills, California

April 10, 2007