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Document And Entity Information - shares | 6 Months Ended |
--- | --- | ---
Jul. 29, 2018 | Aug. 24, 2018
Entity Information [Line Items] |  |
Document Type | 10-Q |
Document Period End Date | Jul. 29, 2018 |
Amendment Flag | false |
Document Fiscal Year Focus | 2019 |
Document Fiscal Period Focus | Q2 |
Entity Registrant Name | SEMTECH CORP |
Entity Central Index Key | 0000088941 |
Current Fiscal Year End Date | --01-27 |
Entity Filer Category | Large Accelerated Filer |
Entity Common Stock, Shares Outstanding |  | 66,222,077

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