-----BEGIN PRIVACY-ENHANCED MESSAGE-----
Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
Originator-Key-Asymmetric:
 MFgwCgYEVQgBAQICAf8DSgAwRwJAW2sNKK9AVtBzYZmr6aGjlWyK3XmZv3dTINen
 TWSM7vrzLADbmYQaionwg5sDW3P6oaM5D3tdezXMm7z1T+B+twIDAQAB
MIC-Info: RSA-MD5,RSA,
 LmvVWLGU6Fv472NyhRUK4r5NPjou7QUGI4IBCk5nyQPY/bktbGbzXc1EEp5EjEyn
 4Dv9LOwWFIUaeBoJo/tR2Q==

<SEC-DOCUMENT>0001134854-03-000008.txt : 20030716
<SEC-HEADER>0001134854-03-000008.hdr.sgml : 20030716
<ACCEPTANCE-DATETIME>20030716154412
ACCESSION NUMBER:		0001134854-03-000008
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20030715
FILED AS OF DATE:		20030716

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			SILICON LABORATORIES INC
		CENTRAL INDEX KEY:			0001038074
		STANDARD INDUSTRIAL CLASSIFICATION:	SEMICONDUCTORS & RELATED DEVICES [3674]
		IRS NUMBER:				742793174
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		4635 BOSTON LN
		CITY:			AUSTIN
		STATE:			TX
		ZIP:			78735

	MAIL ADDRESS:	
		STREET 1:		4635 BOSTON LANE
		CITY:			AUSTIN
		STATE:			TX
		ZIP:			78735

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			WELLAND DAVID R
		CENTRAL INDEX KEY:			0001134854

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-29823
		FILM NUMBER:		03789355

	BUSINESS ADDRESS:	
		STREET 1:		4635 BOSTON LANE
		CITY:			AUSTIN
		STATE:			TX
		ZIP:			78735
		BUSINESS PHONE:		5124168500

	MAIL ADDRESS:	
		STREET 1:		4635 BOSTON LANE
		CITY:			AUSTIN
		STATE:			TX
		ZIP:			78735
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>primary_doc.xml
<DESCRIPTION>PRIMARY DOCUMENT
<TEXT>
<XML>
<?xml version="1.0"?>

<ownershipDocument>

    <documentType>4</documentType>

    <periodOfReport>2003-07-15</periodOfReport>


    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001038074</issuerCik>
        <issuerName>SILICON LABORATORIES INC</issuerName>
        <issuerTradingSymbol>SLAB</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001134854</rptOwnerCik>
            <rptOwnerName>WELLAND DAVID R</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>  </rptOwnerStreet1>
            <rptOwnerStreet2>  </rptOwnerStreet2>
            <rptOwnerCity>  </rptOwnerCity>
            <rptOwnerState>  </rptOwnerState>
            <rptOwnerZipCode>  </rptOwnerZipCode>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>Vice President</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeSecurity>
        <securityTitle>
            <value>Common Stock, $0.0001 par value</value>
        </securityTitle>
        <transactionDate>
            <value>2003-07-15</value>
        </transactionDate>
        <transactionCoding>
            <transactionFormType>4</transactionFormType>
            <transactionCode>S</transactionCode>
            <equitySwapInvolved>0</equitySwapInvolved>
        </transactionCoding>
        <transactionTimeliness>
            <value></value>
        </transactionTimeliness>
        <transactionAmounts>
            <transactionShares>
                <value>20000</value>
            </transactionShares>
            <transactionValue>
                <value>33.1575</value>
            </transactionValue>
            <transactionAcquiredDisposedCode>
                <value>D</value>
            </transactionAcquiredDisposedCode>
        </transactionAmounts>
        <postTransactionAmounts>
            <sharesOwnedFollowingTransaction>
                <value>5050131</value>
            </sharesOwnedFollowingTransaction>
        </postTransactionAmounts>
        <ownershipNature>
            <directOrIndirectOwnership>
                <value>D</value>
            </directOrIndirectOwnership>
        </ownershipNature>
    </nonDerivativeSecurity>


    <ownerSignature>
        <signatureName>Bruce A. Maurer for David R. Welland</signatureName>
        <signatureDate>2003-07-16</signatureDate>
    </ownerSignature>

</ownershipDocument>

</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
-----END PRIVACY-ENHANCED MESSAGE-----