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Proc-Type: 2001,MIC-CLEAR
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<SEC-DOCUMENT>0001413753-09-000089.txt : 20090817
<SEC-HEADER>0001413753-09-000089.hdr.sgml : 20090817
<ACCEPTANCE-DATETIME>20090817170804
ACCESSION NUMBER:		0001413753-09-000089
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		2
CONFORMED PERIOD OF REPORT:	20090813
FILED AS OF DATE:		20090817
DATE AS OF CHANGE:		20090817

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Prutton Simon Martin
		CENTRAL INDEX KEY:			0001436573

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-06395
		FILM NUMBER:		091019894

	MAIL ADDRESS:	
		STREET 1:		200 FLYNN ROAD
		CITY:			CAMARILLO
		STATE:			CA
		ZIP:			93012-8079

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			SEMTECH CORP
		CENTRAL INDEX KEY:			0000088941
		STANDARD INDUSTRIAL CLASSIFICATION:	SEMICONDUCTORS & RELATED DEVICES [3674]
		IRS NUMBER:				952119684
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			0127

	BUSINESS ADDRESS:	
		STREET 1:		200 FLYNN ROAD
		CITY:			CAMARILLO
		STATE:			CA
		ZIP:			93012-8790
		BUSINESS PHONE:		8054982111

	MAIL ADDRESS:	
		STREET 1:		200 FLYNN ROAD
		CITY:			CAMARILLO
		STATE:			CA
		ZIP:			93012-8790
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>edgar.xml
<DESCRIPTION>PRIMARY DOCUMENT
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0303</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2009-08-13</periodOfReport>

    <issuer>
        <issuerCik>0000088941</issuerCik>
        <issuerName>SEMTECH CORP</issuerName>
        <issuerTradingSymbol>SMTC</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001436573</rptOwnerCik>
            <rptOwnerName>Prutton Simon Martin</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>200 FLYNN ROAD</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>CAMARILLO</rptOwnerCity>
            <rptOwnerState>CA</rptOwnerState>
            <rptOwnerZipCode>93012-8790</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>Vice President</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2009-08-13</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>M</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>6250</value>
                    <footnoteId id="F1"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>11985</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value></value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2009-08-13</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>F</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>2235</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>17.41</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>9750</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value></value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>Restricted Stock Unit</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <footnoteId id="F2"/>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2009-08-13</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>M</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>6250</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <footnoteId id="F1"/>
            </exerciseDate>
            <expirationDate>
                <footnoteId id="F3"/>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>6250</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>18750</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value></value>
                </natureOfOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">A portion of the previously reported stock unit award vested on August 13, 2009.</footnote>
        <footnote id="F2">Each Restricted Stock Unit represents the contingent right to one share of the company's common stock.</footnote>
        <footnote id="F3">This grant vests in four equal annual installments beginning on AUgust 13, 2009.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>Simon Martin Prutton by Randall H. Holliday under Power of Attorney dated November 4, 2008 (Copy Attached)</signatureName>
        <signatureDate>2009-08-17</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
<DOCUMENT>
<TYPE>EX-24
<SEQUENCE>2
<FILENAME>attach_1.htm
<DESCRIPTION>SIMON MARTIN PRUTTON POWER OF ATTORNEY DATED NOVEMBER 4, 2008
<TEXT>
<HTML><BODY><PRE>POWER OF ATTORNEY



The undersigned, Simon Martin Prutton, hereby constitutes and

appoints Emeka Chukwu, Randall H. Holliday and Drew L. Alexis, each of them,

jointly and severally, his lawful attorney in fact and agent,

with full power of substitution and resubstitution, for him

and in his name, place and stead, in any and all capacities,

to execute and file with the Securities and Exchange Commission

and any stock exchange or similar authority (or any other

governmental or regulatory authority) Forms ID, 3, 4 and 5 under

Section 16(a) of the Securities Exchange Act of 1934, as amended

(the Act) and the rules thereunder, or any other appropriate

form, and all amendments thereto with all exhibits and any and

all documents required to be filed with respect thereto, relating

to his holdings or beneficial ownership of securities issued by

Semtech Corporation, a corporation organized under the laws of

the State of Delaware (the Corporation), granting unto said

attorneys in fact and agents, and each of them, full power and

authority to do and perform each and every act and thing requisite

or necessary to be done as fully to all intents and purposes as

he might or could do in person, hereby ratifying and confirming

all that said attorneys in fact and agents, and each of them, or

his substitute or substitutes, may do or lawfully cause to

be done by virtue hereof.



The undersigned acknowledges that the foregoing attorneys in fact

and agents, solely by virtue of serving in such capacity at the

request of the undersigned, are not assuming, nor is the Corporation

assuming, any of the undersigneds responsibilities to comply with

Section 16 of the Act.



This Power of Attorney shall remain in full force and effect until

the undersigned is no longer required to file Forms ID, 3, 4 and 5 with

respect to the undersigneds holdings or beneficial ownership of

and transactions in securities issued by the Corporation, unless

earlier revoked by the undersigned in a writing delivered to the

foregoing attorneys in fact.





/s/ Simon Martin Prutton

November 4, 2008

</PRE></BODY></HTML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
-----END PRIVACY-ENHANCED MESSAGE-----
