UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 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): November 20, 2015

PERICOM SEMICONDUCTOR CORPORATION

(Exact Name of Registrant as Specified in Charter)

Registrant’s telephone number, including area code (408) 232-9100

N/A

(Former Name or Former Address, if Changed Since Last Report)

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:

Item 5.07 Submission of Matters to a Vote of Security Holders.

At the special meeting of shareholders held on November 20, 2015, the shareholders of Pericom Semiconductor Corporation (“Pericom” of the “Company”) voted on the proposals set forth below. The proposals are described in detail in the Company’s definitive proxy statement filed with the SEC on October 30, 2015. The preliminary voting results regarding each proposal, as determined by MacKenzie Partners, Inc., the Company’s proxy solicitor, are set forth below. There were 21,891,319 shares issued and outstanding on the record date for the special meeting and entitled to vote thereat, and 16,496,500 shares were represented in person or by proxy at the special meeting, which number constituted a quorum.

Proposal No. 1. Approval of the Agreement and Plan of Merger, dated as of September 2, 2015 (the “Merger Agreement”) by and among Pericom, Diodes Incorporated, a Delaware corporation, and PSI Merger Sub, Inc., a California corporation and a wholly owned subsidiary of Diodes Incorporated, and the merger of PSI Merger Sub, Inc. with and into Pericom (the “Merger”) with Pericom surviving the Merger as a direct wholly owned subsidiary of Diodes Incorporated pursuant thereto (the “Merger Proposal”).

This proposal was approved by the requisite vote of the Company’s shareholders.

Proposal No. 2. Approval to adjourn the special meeting to solicit additional votes to approve the Merger Proposal, if necessary or appropriate.

Adjournment of the special meeting was deemed not necessary or appropriate because there was a quorum present and there were sufficient votes at the time of the special meeting to approve the adoption of the Merger Agreement.

Proposal No. 3. Approval, on a non-binding, advisory basis, of certain compensation that will or may become payable to certain named executive officers of Pericom that is based on or otherwise relates to the Merger.

Item 8.01 Other Events.

On November 20, 2015, the Company issued a press release announcing the preliminary results of the special meeting held on November 20, 2015. A copy of the press release is attached hereto as Exhibit 99.1 and is incorporated by reference herein.

Item 9.01. Financial Statements and Exhibits.

SIGNATURES

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

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