UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, DC 20549

FORM 8-K

CURRENT REPORT

PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934

Date of report (Date of earliest event reported): July 25, 2013

SILICON LABORATORIES INC.

(Exact Name of Registrant as Specified in Charter)

Registrant’s telephone number, including area code: (512) 416-8500

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions (see General Instruction A.2. below):

o Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)

o Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)

o Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))

o Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))

Item 2.02. Results of Operations and Financial Condition

On July 25, 2013, Silicon Laboratories Inc. (“Silicon Laboratories”) issued a press release describing its results of operations for its fiscal quarter ended June 29, 2013. A copy of the press release is attached as Exhibit 99 to this report.

Item 9.01. Financial Statements and Exhibits

(d) Exhibits.

Use of Non-GAAP Financial Information

From time to time, Silicon Laboratories provides certain non-GAAP financial measures as additional information relating to its operating results.  The non-GAAP financial measurements provided in the press release furnished herewith do not replace the presentation of Silicon Laboratories’ GAAP financial results. These additional measurements merely provide supplemental information to assist investors in analyzing Silicon Laboratories’ financial position and results of operations; however, these measures are not in accordance with, or an alternative to, GAAP and may be different from non-GAAP measures used by other companies. Silicon Laboratories has chosen to provide this information to investors because it believes that such supplemental information enables them to perform meaningful comparisons of past, present and future operating results, and as a means to highlight the results of core ongoing operations.

Pursuant to the requirements of Regulation G, we have provided in the press release furnished with this report a reconciliation of the non-GAAP financial measures to the most directly comparable GAAP financial measures.

The information in this report, including the exhibit hereto, shall not be deemed to be “filed” for purposes of Section 18 of the Securities Exchange Act of 1934, as amended, or otherwise subject to the liability of that section.  The information contained therein and in the accompanying exhibit shall not be incorporated by reference into any filing with the U.S. Securities and Exchange Commission made by Silicon Laboratories, whether made before or after the date hereof, regardless of any general incorporation language in such filing.

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SIGNATURE

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.

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EXHIBIT INDEX

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Exhibit 99

SILICON LABS ANNOUNCES SECOND QUARTER 2013 RESULTS

— Record Revenue in Timing and Broadcast Video Product Lines —

AUSTIN, Texas — July 25, 2013 — Silicon Labs (NASDAQ: SLAB), a leader in high-performance, analog-intensive, mixed-signal integrated circuits (ICs), today reported results for its second quarter ended June 29, 2013. Overall revenue in the second quarter was $141.5 million, an increase of 4.3 percent compared with the same period a year ago and down 2.6 percent sequentially.

Financial Highlights

On a GAAP basis, gross margins were 62.7 percent, a sequential improvement resulting from a shift in the product mix favoring timing devices. GAAP R&D investment was stable on a sequential basis and increased year over year to $37.4 million. GAAP SG&A expenses increased both sequentially and year over year to $32.4 million. Resulting GAAP operating income as a percentage of revenue decreased sequentially and increased year over year to 13.4 percent. GAAP diluted earnings per share were $0.29, down 37 percent sequentially due primarily to acquisition-related items and income taxes and also down 38 percent year over year.

The non-GAAP results exclude the impact of stock compensation and certain other items as set forth in the reconciliation table below. Non-GAAP gross margins increased sequentially to 62.9 percent. On a non-GAAP basis, R&D increased slightly to $33.6 million, and SG&A decreased to $27.3 million. Non-GAAP operating income in the quarter was 19.9 percent. Non-GAAP diluted earnings per share in the quarter were $0.50, down slightly compared with the second quarter of 2012.

Business Highlights

On July 1, the company closed its acquisition of Energy Micro, a leader in energy-friendly ARM® Cortex™-M based microcontrollers (MCUs) and radios. Adding to Silicon Labs’ already strong MCU, radio and software solutions, this strategic acquisition accelerates growth opportunities and positions the company as the foremost innovator in embedded solutions for the growing Internet of Things and green energy markets.

In the Broad-based business, revenue and gross margin results were particularly strong from timing devices. The recently introduced Si50x CMEMS® oscillator product family, featuring the industry’s first single-die MEMS oscillator solution and designed to replace crystal oscillators in high-volume applications, is expected to begin generating significant revenue in 2014.

Although revenue from Broadcast products overall was slightly down sequentially, the company achieved record revenue in video products during the second quarter, marking the fourth consecutive quarter of video revenue growth.

“During the quarter, we achieved two important milestones—the strategic acquisition of Energy Micro and the groundbreaking introduction of our new CMEMS technology platform and oscillator product line,” said Tyson Tuttle, CEO of Silicon Labs. “We believe these accomplishments will help drive Silicon Labs’ growth in our Broad-based products, which represent our fastest growing and largest market opportunity.”

The company expects revenue for the third quarter to be in the range of $144 to $149 million.

Webcast and Conference Call

A conference call discussing the quarterly results will follow this press release at 7:30 a.m. Central time. An audio webcast will be available simultaneously on Silicon Labs’ website under Investor Relations (www.silabs.com). A replay will be available after the call at the same website listed above or by calling 1 (855) 859-2056 or 1 (404) 537-3406 (international) and by entering 39717385. The replay will be available through Aug. 25.

About Silicon Labs

Silicon Labs is an industry leader in the innovation of high-performance, analog-intensive, mixed-signal ICs. Developed by a world-class engineering team with unsurpassed expertise in mixed-signal design, Silicon Labs’ diverse portfolio of patented semiconductor solutions offers customers significant advantages in performance, size and power consumption. For more information about Silicon Labs, please visit www.silabs.com.

Forward-Looking Statements

This press release contains forward-looking statements based on Silicon Labs’ current expectations. The words “believe,” “estimate,” “expect,” “intend,” “anticipate,” “plan,” “project,” “will” and similar phrases as they relate to Silicon Labs are intended to identify such forward-looking statements. These forward-looking statements reflect the current views and assumptions of Silicon Labs and are subject to various risks and uncertainties that could cause actual results to differ materially from expectations. Among the factors that could cause actual results to differ materially from those in the forward-looking statements are the following: risks that Silicon Labs may not be able to maintain its historical growth; quarterly fluctuations in revenues and operating results; difficulties developing new products that achieve market acceptance; dependence on a limited number of products and customers; intellectual property litigation risks; risks associated with acquisitions and divestitures; product liability risks; difficulties managing our distributors, manufacturers and subcontractors; inventory-related risks; difficulties managing international activities; risks that Silicon Labs may not be able to manage strains associated with its growth; credit risks associated with our accounts receivable; dependence on key personnel; stock price volatility; geographic concentration of manufacturers, assemblers, test service providers and customers in Asia that subjects Silicon Labs’ business and results of operations to risks of natural disasters, epidemics, war and political unrest; debt-related risks; capital-raising risks; the competitive and cyclical nature of the semiconductor industry; average selling prices of products may decrease significantly and rapidly; information technology risks; conflict mineral risks and other factors that are detailed in the SEC filings of Silicon Laboratories Inc. Silicon Labs disclaims any intention or obligation to update or revise any forward-looking statements, whether as a result of new information, future events or otherwise. References in this press release to Silicon Labs shall mean Silicon Laboratories Inc.

Note to editors: Silicon Laboratories, Silicon Labs and the Silicon Labs logo are trademarks of Silicon Laboratories Inc. All other product names noted herein may be trademarks of their respective holders.

CONTACT: Deborah Stapleton, +1 650.470.4200, Deborah.Stapleton@silabs.com

Silicon Laboratories Inc.

Condensed Consolidated Statements of Income

 (In thousands, except per share data)

(Unaudited)

 Unaudited Reconciliation of GAAP to Non-GAAP Financial Measures

(In thousands, except per share data)

Silicon Laboratories Inc.

Condensed Consolidated Balance Sheets

(In thousands, except per share data)

(Unaudited)

Silicon Laboratories Inc.

Condensed Consolidated Statements of Cash Flows

(In thousands)

(Unaudited)

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