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): June 8, 2014

HITTITE MICROWAVE CORPORATION

(Exact Name of Registrant as Specified in Charter)

2 Elizabeth Drive, Chelmsford, Massachusetts 01824

(Address of principal executive offices) (Zip Code)

(978) 250-3343

(Registrant’s telephone number, including area code)

(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 (see General Instruction A.2. below).

On June 9, 2014, Hittite Microwave Corporation (the “Company”) entered into an Agreement and Plan of Merger (the “Merger Agreement”) with Analog Devices, Inc. (“Analog”), and BBAC Corp., a wholly owned subsidiary of Analog (“Purchaser”). Pursuant to the terms of the Merger Agreement, Purchaser will commence a tender offer (the “Offer”) to purchase all of the outstanding shares of common stock, par value $0.01 per share, of the Company (the “Company Common Stock”), at a price per share of $78.00, net to the seller in cash, without interest (the “Offer Price”), and subject to deduction for any required withholding of taxes. Purchaser is obligated to commence the Offer as promptly as practicable, and in any event within 10 business days following the date of the Merger Agreement, and the Offer will remain open for 20 business days from the date of commencement of the Offer, subject to extension in accordance with the terms of the Merger Agreement.

The consummation of the Offer is subject to customary closing conditions, including, among other things, (i) the valid tender of shares of Company Common Stock representing at least a majority of the total outstanding shares of Company Common Stock, calculated on a fully diluted basis, (ii) the expiration or termination of all applicable waiting periods under the Hart-Scott-Rodino Antitrust Improvements Act of 1976, as amended (the “HSR Act”), and (iii) other conditions to the Offer set forth in Annex I to the Merger Agreement. The consummation of the Offer is not subject to any financing condition.

Upon the completion of the Offer, and subject to the satisfaction or waiver of the conditions set forth in the Merger Agreement, Purchaser will be merged with and into the Company, with the Company surviving as a wholly owned subsidiary of Analog (the “Merger”). The Merger Agreement provides that the Merger will be governed by Section 251(h) of the Delaware General Corporation Law (the “DGCL”) and shall be effected by Purchaser and the Company as soon as practicable following the consummation of the Offer without a stockholders meeting.

At the effective time of the Merger (the “Effective Time”), each outstanding share of Company Common Stock, other than shares of Company Common Stock owned by the Company, Analog or Purchaser immediately prior to the Effective Time, or by stockholders who have validly exercised their appraisal rights under Delaware law and other than unvested restricted stock awards held by employees, as more fully described below, will be canceled and converted into the right to receive an amount in cash equal to the Offer Price, payable to the holder thereof on the terms and subject to the conditions set forth in the Merger Agreement.

The Company, Analog and Purchaser have made customary representations, warranties and covenants in the Merger Agreement. The Company’s covenants include, among other things, covenants regarding the operation of the Company’s business prior to the Effective Time and covenants restricting the ability of the Company to solicit third-party proposals relating to alternative transactions or provide information or enter into discussions in connection with alternative transactions, subject to certain exceptions to permit the board of directors of the Company (the “Company Board”) to comply with its fiduciary duties. Notwithstanding the limitations applicable pursuant to the “no shop” restrictions set forth in the Merger Agreement, prior to the consummation of the Offer, under specified circumstances the Company Board may change its recommendation in connection with an intervening event that was not known or

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reasonably foreseeable as of the date of the Merger Agreement, or in connection with an alternative proposal that does not result from breach of the “no shop” restrictions and that the Company Board determines in good faith constitutes a superior proposal (in which latter case the Company may also terminate the Merger Agreement to enter into such superior proposal upon payment of the termination fee, as discussed below). Before the Company Board may change its recommendation in connection with a superior proposal, or terminate the Merger Agreement to accept a superior proposal, the Company must provide Analog with a customary four business day match right, subject to an additional three business day match right in the event of a material change to such superior proposal.

The Merger Agreement also includes customary termination provisions for both the Company and Analog and provides that, in connection with the termination of the Merger Agreement, under certain circumstances, the Company must pay Analog a termination fee of $86.5 million, including due to termination of the Merger Agreement by the Company to accept a superior proposal.

Each party is required to use its reasonable best efforts to satisfy the closing conditions relating to required governmental or third party consents, including by making required filings under the HSR Act, provided that Analog will not be obligated to sell, hold separate or dispose of any business or assets, or to agree to take any such action.

The foregoing summary of the Merger Agreement, the Offer and the Merger does not purport to be complete and is subject to, and qualified in its entirety by, the full text of the Merger Agreement, a copy of which is attached hereto as Exhibit 2.1 and the terms of which are incorporated herein by reference.

The Merger Agreement has been attached hereto pursuant to applicable rules and regulations of the Securities and Exchange Commission (“SEC”) in order to provide investors and stockholders with information regarding its terms. However, it is not intended to provide any other factual information about the Company, Analog, their respective subsidiaries and affiliates, or any other party. In particular, the representations, warranties and covenants contained in the Merger Agreement have been made only for the purpose of the Merger Agreement and, as such, are intended solely for the benefit of the parties to the Merger Agreement. In many cases, these representations, warranties and covenants are made as of specific dates, subject to limitations agreed upon by the parties and qualified by certain disclosures exchanged by the parties in connection with the execution of the Merger Agreement. Furthermore, many of the representations and warranties in the Merger Agreement are the result of a negotiated allocation of contractual risk among the parties and, taken in isolation, do not necessarily reflect facts about the Company, Analog, their respective subsidiaries and affiliates or any other party. Likewise, any references to materiality contained in the representations and warranties may not correspond to concepts of materiality applicable to investors or stockholders. Information concerning the subject matter of the representations and warranties may change after the date of the Merger Agreement and these changes may not be fully reflected in the Company’s public disclosures.

AS A RESULT OF THE FOREGOING, INVESTORS AND STOCKHOLDERS ARE STRONGLY ENCOURAGED NOT TO RELY ON THE REPRESENTATIONS, WARRANTIES AND COVENANTS CONTAINED IN THE MERGER AGREEMENT, OR ON ANY DESCRIPTIONS THEREOF, AS ACCURATE CHARACTERIZATIONS OF THE STATE OF FACTS OR CONDITION OF THE COMPANY OR ANY OTHER PARTY.

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Forward-Looking Statements

Certain statements in this Current Report on Form 8-K and in the press release attached hereto may constitute “forward-looking statements.” Such statements relate to a variety of matters, including but not limited to: the timing and anticipated completion of the Offer and the proposed Merger; and other statements that are not purely statements of historical fact. These forward-looking statements are made on the basis of the current beliefs, expectations and assumptions of the management of the Company and Analog and are subject to significant risks and uncertainty. Investors are cautioned not to place undue reliance on any such forward-looking statements. All such forward-looking statements speak only as of the date they are made, and neither the Company nor Analog undertakes any obligation to update or revise these statements, whether as a result of new information, future events or otherwise, except as required by law.

Factors that could cause actual results to differ materially from the forward-looking statements contained herein include, but are not limited to: potential adverse reactions or changes to business relationships resulting from the announcement of the proposed acquisition of the Company; unexpected costs, charges or expenses resulting from the proposed acquisition of the Company; litigation or adverse judgments relating to the proposed acquisition of the Company; risks relating to the consummation of the proposed acquisition of the Company, including the risk that the closing conditions to the Offer or the proposed Merger will not be satisfied; any difficulties associated with requests or directions from governmental authorities resulting from their reviews of the transaction; and any changes in general economic and/or industry-specific conditions. Additional factors that could cause actual results to differ materially from those described in the forward-looking statements are set forth under the heading “Item 1A—Risk Factors” in the Company’s Annual Report on Form 10-K for the fiscal year ended December 31, 2013, which was filed with the SEC on February 26, 2014, and in Analog’s Annual Report on Form 10-K for the fiscal year ended November 2, 2013, which was filed with the SEC on November 26, 2013, as well as in subsequent reports on Forms 10-Q and 8-K and other filings made with the SEC by the Company and Analog.

Additional Information and Where to Find It

No statement in this document or the attached exhibits is an offer to purchase or a solicitation of an offer to sell securities. The Offer for the shares of Company Common Stock has not commenced. Analog intends to file a tender offer statement on Schedule TO with the SEC, and the Company intends to file a solicitation/recommendation statement on Schedule 14D-9, each with respect to the Offer described in this Current Report on Form 8-K and the exhibits attached hereto. Any offers to purchase or solicitations of offers to sell will be made only pursuant to such tender offer statements. The tender offer statement on Schedule TO (including an offer to purchase, a related letter of transmittal and other offer documents) and the related solicitation/recommendation statement on Schedule 14D-9 will contain important information, including the various terms of, and conditions to, the Offer, which should be read carefully by the Company’s stockholders before they make any decision with respect to the Offer. Such materials, when prepared and ready for release, will be made available to the

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Company’s stockholders at no expense to them. In addition, at such time, such materials (and all other offer documents filed with the SEC) will be available at no charge on the SEC’s website at www.sec.gov and may also be obtained by directing a request to the Company, at Hittite Microwave Corporation, attention William W. Boecke, Chief Financial Officer, 2 Elizabeth Drive, Chelmsford, Massachusetts 01824, telephone (978) 250-3343, or to Analog, at Analog Devices, Inc., attention Director of Investor Relations, One Technology Way, Norwood, Massachusetts 02062; telephone: (781) 461-3282.

Item 5.02. Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers; Compensatory Arrangements of Certain Officers.

Concurrently with the Company’s entry into the Merger Agreement, each of the current directors of the Company tendered his or her resignation as a director of the Company, conditioned upon and effective as of the Effective Time.

In connection with the entry into the Merger Agreement, the Company’s Board of Directors also adopted an amendment (the “2005 Plan Amendment”) to the Company’s 2005 Stock Incentive Plan (the “2005 Plan”). The 2005 Plan Amendment provides that Unvested Company RSUs and Unvested Company RSAs that are cancelled at the Effective Time, will be replaced with awards denominated in shares of the common stock, par value $0.16 2/3 per share, of Analog or cash, as applicable, in accordance with the terms of the Merger Agreement.

Also on June 9, 2014 and in connection with the entry into the Merger Agreement, the Company entered into an amendment (the “Employment Agreement Amendment”) to its employment agreement dated March 13, 2013, with its Chief Executive Officer, Rick D. Hess, as previously amended on August 8, 2013 and April 9, 2014 (the “Employment Agreement”). Pursuant to the terms of the Employment Agreement Amendment, payments received by Mr. Hess pursuant to the Employment Agreement in connection with a Change of Control (as that term is defined in the Employment Agreement) will not be subject to reduction in the event that any such payments would be subject to excise tax imposed under Section 4999 of the U.S. Internal Revenue Code, as amended, and the vesting schedule of the Retention Award referred to in the Employment Agreement was modified to, among other things, eliminate the performance condition to its vesting and provide for time-based vesting over a period of four years.

On June 8, 2014, the Company’s Board of Directors approved an amendment to the Company’s Amended and Restated By-laws to provide that the exclusive forum for

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will be the Court of Chancery of the State of Delaware or, in the event that the Court of Chancery does not have jurisdiction, the federal district court for the District of Delaware or other state courts of the State of Delaware.

A copy of the amendment to the Company’s Amended and Restated By-laws is attached hereto as Exhibit 3.1 and incorporated herein by reference.

On June 9, 2014, the Company and Analog issued a joint press release announcing the execution of the Merger Agreement. A copy of the press release is attached hereto as Exhibit 99.1 and is incorporated herein by reference.

On June 9, 2014, the Company and Analog held a joint investor conference call in connection with the announcement of the execution of the Merger Agreement. A transcript of the conference call is attached hereto as Exhibit 99.2 and is incorporated herein by reference.

On June 9, 2014 the Company made available the frequently asked questions attached hereto as Exhibit 99.3, which is incorporated herein by reference.

On June 9, 2014 the Company made available to its employees the presentation attached hereto as Exhibit 99.4, which is incorporated herein by reference.

On June 9, 2014 the Company distributed to its employees the letter attached hereto as Exhibit 99.5, which is incorporated herein by reference.

(d) Exhibits.

2.1 Agreement and Plan of Merger dated June 9, 2014, by and among Analog Devices, Inc., BBAC Corp. and Hittite Microwave Corporation.

3.1 Amendment to Amended and Restated By-laws of Hittite Microwave Corporation.

99.1 Press release entitled “Analog Devices to Acquire Hittite Microwave Corporation.”

99.2 Transcript of joint investor conference call held by the Company and Analog on June 9, 2014.

99.3 Frequently asked questions made available by the Company on June 9, 2014.

99.4 Employee presentation made available by the Company on June 9, 2014.

99.5 Letter to Company employees distributed on June 9, 2014.

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SIGNATURES

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 thereunto duly authorized.

Date: June 9, 2014

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Exhibit Index

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