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 
  
  
  
                               June 23, 1998          
                     (Date of earliest event reported) 
  
  
                            UNITRODE CORPORATION                   
           (Exact name of Registrant as specified in its charter) 
  
  
  Maryland                     1-5609                      04-2271188    
 (State of               (Commission File No.)           (IRS Employer 
 Incorporation)                                        Identification No.) 
  
  
                7 Continental Boulevard, Merrimack, NH 03054        
        (Address of principal executive offices, including zip code) 
  
  
                               (603) 424-2410                  
            (Registrant's telephone number, including area code) 
  
  
                                Not Applicable                      
       (Former name or former address, if changed since last report) 
  
  

 Item 5.   Other Events. 

      On June 23, 1998, Unitrode Corporation a Maryland corporation (the
 "Registrant"), Merrimack Corporation, a Delaware corporation and a wholly
 owned subsidiary of Unitrode ("Sub") and BENCHMARQ Microelectronics, Inc.,
 a Delaware corporation ("BENCHMARQ"), agreed to amend their previously
 reported Agreement and Plan of Merger, dated as of March 2, 1998 (the
 "Merger Agreement"), pursuant to an Amendment to Agreement and Plan of
 Merger (the Merger Agreement, as so amended, the "Amended Merger
 Agreement").   
  
      Under the terms of the Amended Merger Agreement, BENCHMARQ
 stockholders will receive one share (the "Exchange Ratio") of the
 Registrant's common stock, par value $.01 per share, for each outstanding
 share of BENCHMARQ common stock, par value $.001 per share ("BENCHMARQ
 Common Stock") and no adjustments to the Exchange Ratio will be made
 regardless of the trading value of the stock.  The other changes to the
 Merger Agreement effected by the Amended Merger Agreement relate to certain
 representations and warranties, and the termination and termination fees
 provisions. 
  
      On June 23, 1998, the Registrant and BENCHMARQ amended the Stock
 Option Agreement  (the "Stock Option Agreement") dated as of March 2, 1998
 (the Stock option Agreement, as so amended, the "Amended Stock Option
 Agreement") to modify certain termination events and to change the exercise
 price of the option to $11.13 per share. 
  
      On June 23, 1998, the Registrant and certain stockholders of BENCHMARQ
 amended Voting Agreement (the "Voting Agreement") dated as of March 2, 1998
 (the Voting Agreement, as so amended, the "Amended Voting Agreement") to
 reflect the obligation of such stockholders to vote their shares of
 BENCHMARQ Common Stock at a meeting of BENCHMARQ stockholders in favor of
 the transactions contemplated by the Amended Merger Agreement. 
  
      The foregoing is qualified in its entirety by reference to the
 Amendment to Agreement and Plan of Merger, the Amendment to Stock Option
 Agreement and the Amendment to Voting Agreement, and the Registrant's and
 BENCHMARQ's joint press release dated June 24, 1998, copies of which are
 attached as exhibits hereto and which are incorporated by reference herein. 


 Item 7.   Financial Statements, Pro Forma Financial Information and
           Exhibits 
  
 Exhibit No.              Description 
  
      2.1       Amendment to Merger Agreement, dated as of June 23, 1998, by
                and among Unitrode Corporation, Merrimack Corporation and
                BENCHMARQ Microelectronics, Inc. 
  
      2.2       Amendment to Stock Option Agreement dated as of June 23, 1998,
                by and among Unitrode Corporation, Merrimack Corporation and
                BENCHMARQ Microelectronics, Inc. 
       
      2.3       Amendment to Voting Agreement, dated as of June 23, 1998, by
                and among Unitrode Corporation, Merrimack Corporation and
                BENCHMARQ Microelectronics, Inc. 
   
      99.1      Form of Joint Press Release issued by Unitrode Corporation
                and BENCHMARQ Microelectronics, Inc. on June 24, 1998. 


  
                                SIGNATURE 
  
           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. 
  
  
                                  UNITRODE CORPORATION 
  
  
  
                                  By: /s/ Robert J. Richardson 
                                     -------------------------
                                          Robert J. Richardson 
  
  
 Date:  June 24, 1998


  
                               Exhibit Index 

                                                                   Sequential
 Exhibit  No.    Description                                       Page No.

   2.1           Amendment to Merger Agreement, dated
                 as of June 23, 1998, by and among
                 Unitrode Corporation, Merrimack Corporation
                 and BENCHMARQ Microelectronics, Inc.

   2.2           Amendment to Stock Option Agreement dated
                 as of June 23, 1998, by and among Unitrode 
                 Corporation, Merrimack Corporation and
                 BENCHMARQ Microelectronics, Inc.
 
   2.3           Amendment to Voting Agreement, dated as of
                 June 23, 1998, by and among Unitrode Corporation,
                 Merrimack Corporation and BENCHMARQ 
                 Microelectronics, Inc.
 
   99.1          Form of Joint Press Release issued by
                 Unitrode Corporation and BENCHMARQ
                 Microelectronics, Inc. on June 24, 1998.
[{"type": "8-K", "sequence": "1", "secsgml_size_bytes": 6020}]
{"company-data": {"conformed-name": "UNITRODE CORP", "cik": "0000101911", "assigned-sic": "3674", "irs-number": "042271186", "state-of-incorporation": "MD", "fiscal-year-end": "0131"}, "filing-values": {"form-type": "8-K", "act": "34", "file-number": "001-05609", "film-number": "98653202"}, "business-address": {"street1": "7 CONTINENTAL BLVD", "city": "MERRIMACK", "state": "NH", "zip": "03054", "phone": "6034242410"}, "mail-address": {"street1": "7 CONTINENTAL BLVD", "city": "MERRIMACK", "state": "NH", "zip": "03054"}}
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 
  
  
  
                               June 23, 1998          
                     (Date of earliest event reported) 
  
  
                            UNITRODE CORPORATION                   
           (Exact name of Registrant as specified in its charter) 
  
  
  Maryland                     1-5609                      04-2271188    
 (State of               (Commission File No.)           (IRS Employer 
 Incorporation)                                        Identification No.) 
  
  
                7 Continental Boulevard, Merrimack, NH 03054        
        (Address of principal executive offices, including zip code) 
  
  
                               (603) 424-2410                  
            (Registrant's telephone number, including area code) 
  
  
                                Not Applicable                      
       (Former name or former address, if changed since last report) 
  
  

 Item 5.   Other Events. 

      On June 23, 1998, Unitrode Corporation a Maryland corporation (the
 "Registrant"), Merrimack Corporation, a Delaware corporation and a wholly
 owned subsidiary of Unitrode ("Sub") and BENCHMARQ Microelectronics, Inc.,
 a Delaware corporation ("BENCHMARQ"), agreed to amend their previously
 reported Agreement and Plan of Merger, dated as of March 2, 1998 (the
 "Merger Agreement"), pursuant to an Amendment to Agreement and Plan of
 Merger (the Merger Agreement, as so amended, the "Amended Merger
 Agreement").   
  
      Under the terms of the Amended Merger Agreement, BENCHMARQ
 stockholders will receive one share (the "Exchange Ratio") of the
 Registrant's common stock, par value $.01 per share, for each outstanding
 share of BENCHMARQ common stock, par value $.001 per share ("BENCHMARQ
 Common Stock") and no adjustments to the Exchange Ratio will be made
 regardless of the trading value of the stock.  The other changes to the
 Merger Agreement effected by the Amended Merger Agreement relate to certain
 representations and warranties, and the termination and termination fees
 provisions. 
  
      On June 23, 1998, the Registrant and BENCHMARQ amended the Stock
 Option Agreement  (the "Stock Option Agreement") dated as of March 2, 1998
 (the Stock option Agreement, as so amended, the "Amended Stock Option
 Agreement") to modify certain termination events and to change the exercise
 price of the option to $11.13 per share. 
  
      On June 23, 1998, the Registrant and certain stockholders of BENCHMARQ
 amended Voting Agreement (the "Voting Agreement") dated as of March 2, 1998
 (the Voting Agreement, as so amended, the "Amended Voting Agreement") to
 reflect the obligation of such stockholders to vote their shares of
 BENCHMARQ Common Stock at a meeting of BENCHMARQ stockholders in favor of
 the transactions contemplated by the Amended Merger Agreement. 
  
      The foregoing is qualified in its entirety by reference to the
 Amendment to Agreement and Plan of Merger, the Amendment to Stock Option
 Agreement and the Amendment to Voting Agreement, and the Registrant's and
 BENCHMARQ's joint press release dated June 24, 1998, copies of which are
 attached as exhibits hereto and which are incorporated by reference herein. 

 Item 7.   Financial Statements, Pro Forma Financial Information and
           Exhibits 
  
 Exhibit No.              Description 
  
      2.1       Amendment to Merger Agreement, dated as of June 23, 1998, by
                and among Unitrode Corporation, Merrimack Corporation and
                BENCHMARQ Microelectronics, Inc. 
  
      2.2       Amendment to Stock Option Agreement dated as of June 23, 1998,
                by and among Unitrode Corporation, Merrimack Corporation and
                BENCHMARQ Microelectronics, Inc. 
       
      2.3       Amendment to Voting Agreement, dated as of June 23, 1998, by
                and among Unitrode Corporation, Merrimack Corporation and
                BENCHMARQ Microelectronics, Inc. 
   
      99.1      Form of Joint Press Release issued by Unitrode Corporation
                and BENCHMARQ Microelectronics, Inc. on June 24, 1998. 

  
                                SIGNATURE 
  
           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. 
  
  
                                  UNITRODE CORPORATION 
  
  
  
                                  By: /s/ Robert J. Richardson 
                                     -------------------------
                                          Robert J. Richardson 
  
  
 Date:  June 24, 1998

  
                               Exhibit Index 

                                                                   Sequential
 Exhibit  No.    Description                                       Page No.

   2.1           Amendment to Merger Agreement, dated
                 as of June 23, 1998, by and among
                 Unitrode Corporation, Merrimack Corporation
                 and BENCHMARQ Microelectronics, Inc.

   2.2           Amendment to Stock Option Agreement dated
                 as of June 23, 1998, by and among Unitrode 
                 Corporation, Merrimack Corporation and
                 BENCHMARQ Microelectronics, Inc.
 
   2.3           Amendment to Voting Agreement, dated as of
                 June 23, 1998, by and among Unitrode Corporation,
                 Merrimack Corporation and BENCHMARQ 
                 Microelectronics, Inc.
 
   99.1          Form of Joint Press Release issued by
                 Unitrode Corporation and BENCHMARQ
                 Microelectronics, Inc. on June 24, 1998.