Silicon Laboratories (SLAB) 10-Q 2018 Q1 Quarterly report

Exhibit 32.1

Certification of Chief Executive Officer and Chief Financial Officer

Pursuant to 18 U.S.C. § 1350, as created by Section 906 of the Sarbanes-Oxley Act of 2002, each of the undersigned officers of Silicon Laboratories Inc. (the “Company”) hereby certify that:

(i)   the accompanying Quarterly Report on Form 10-Q of the Company for the fiscal quarter ended March 31, 2018 as filed with the Securities and Exchange Commission (the “Report”) fully complies with the requirements of Section 13(a) or Section 15(d), as applicable, of the Securities Exchange Act of 1934; and

(ii)  the information contained in the Report fairly presents, in all material respects, the financial condition and results of operations of the Company.

A signed original of this written statement required by Section 906 has been provided to the Company and will be retained by the Company and furnished to the Securities Exchange Commission or its staff upon request.

Date: April 25, 2018

/s/ G. Tyson Tuttle

G. Tyson Tuttle

President and

Chief Executive Officer

/s/ John C. Hollister

John C. Hollister

Senior Vice President and

Chief Financial Officer