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Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
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MIC-Info: RSA-MD5,RSA,
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 O2N7KIMw3UNTyMKVZa4hDA==

<SEC-DOCUMENT>0001140361-11-004308.txt : 20110126
<SEC-HEADER>0001140361-11-004308.hdr.sgml : 20110126
<ACCEPTANCE-DATETIME>20110126191003
ACCESSION NUMBER:		0001140361-11-004308
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20100827
FILED AS OF DATE:		20110126
DATE AS OF CHANGE:		20110126

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			LANG GREGORY S
		CENTRAL INDEX KEY:			0001230191

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-29617
		FILM NUMBER:		11550310

	MAIL ADDRESS:	
		STREET 1:		C/O INTEGRATED DEVICE TECHNOLOGY, INC.
		STREET 2:		6024 SILVER CREEK VALLEY ROAD
		CITY:			SAN JOSE
		STATE:			CA
		ZIP:			95138

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			INTERSIL CORP/DE
		CENTRAL INDEX KEY:			0001096325
		STANDARD INDUSTRIAL CLASSIFICATION:	SEMICONDUCTORS & RELATED DEVICES [3674]
		IRS NUMBER:				593590018
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		1001 MURPHY RANCH ROAD
		STREET 2:		SUITE 1
		CITY:			MILPITAS
		STATE:			CA
		ZIP:			95035
		BUSINESS PHONE:		408-432-8888

	MAIL ADDRESS:	
		STREET 1:		1650 ROBERT J. CONLAN BLVD. NE
		CITY:			PALM BAY
		STATE:			FL
		ZIP:			32905

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	INTERSIL HOLDING CO
		DATE OF NAME CHANGE:	19991005
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>doc1.xml
<DESCRIPTION>FORM 4
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0303</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2010-08-27</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001096325</issuerCik>
        <issuerName>INTERSIL CORP/DE</issuerName>
        <issuerTradingSymbol>ISIL</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001230191</rptOwnerCik>
            <rptOwnerName>LANG GREGORY S</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O INTERSIL CORPORATION</rptOwnerStreet1>
            <rptOwnerStreet2>1001 MURPHY RANCH ROAD</rptOwnerStreet2>
            <rptOwnerCity>MILPITAS</rptOwnerCity>
            <rptOwnerState>CA</rptOwnerState>
            <rptOwnerZipCode>95035</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle></officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2010-08-27</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>P</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>5000</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>10.489</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>9266</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <derivativeTable></derivativeTable>

    <footnotes></footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>Debbie Ceraolo-Johnson, by Power of Attorney</signatureName>
        <signatureDate>2011-01-26</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
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