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 
  
  
                              February 28, 1998          
                     (Date of earliest event reported) 
  
  
                             UNITRODE CORPORATION            
           (Exact name of Registrant as specified in its charter) 
  
  
  Maryland                    1-5609             04-2271186
 (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 March 2, 1998, Unitrode Corporation (the "Registrant") entered into

 an Agreement and Plan of Merger (the "Merger Agreement"), by and among the
 Registrant, Merrimack Corporation, a Delaware 
corporation and wholly owned 
 subsidiary of the Registrant ("Newco"), and 
BENCHMARQ Microelectronics, Inc.,
 a Delaware corporation ("Benchmarq"). 
 Pursuant to the Merger Agreement,
 among other things, Newco will be merged 
with and into Benchmarq (the 
 "Merger") and Benchmarq will become a wholly 
owned subsidiary of the
 Registrant.  At the effective time of the Merger, 
each share of Benchmarq's
 common stock, par value $.001 per share 
("Benchmarq Common Stock"), shall
 be cancelled and extinguished and 
converted into the right to receive one 
 share of the Registrant's common 
stock, par value $.01 per share ("Registrant
 Common Stock"), and the 
associated preferred stock purchase right, subject
 to adjustment as
 described below (the "Exchange Ratio").  In the event that
 the average of 
the mean high and low per share trading prices as reported in
 The Wall 
Street Journal for the New York Stock Exchange, Inc. Composite 
 Transactions 
for the twenty trading days ending on the tenth day prior to 
 the Benchmarq 
stockholders' meeting (the "Pre-Closing Average") is less than
 $16.00, the 
Exchange Ratio will be adjusted so that each share of Benchmarq
 Common
 Stock will be converted into the right to receive a number of shares of

 Registrant Common Stock equal to the quotient obtained by dividing $16.00

 by the Pre-Closing Average, provided, however, that the Exchange Ratio

 shall in no event be higher than 1.33.  In the event that the Pre-Closing

 Average is greater than $24.00, then the Exchange Ratio shall be adjusted

 so that each share of Benchmarq Common Stock will be converted into the

 right to receive a number of shares of Registrant Common Stock equal to the

 quotient obtained by dividing $24.00 by the Pre-Closing Average. In

 addition to the approval of the Merger Agreement by Benchmarq's

 stockholders, the Merger is subject to, among other things, the approval of

 the issuance of the shares of Registrant Common Stock in the Merger by the



 stockholders of the Registrant and other customary closing conditions

 including expiration of the applicable waiting period under the Hart-Scott-

 Rodino Antitrust Improvements Act of 1976, as amended. It is also a

 condition to closing that the parties receive assurances that the Merger

 will constitute a reorganization within the meaning of Section 368(a) of

 the Internal Revenue Code of 1986, as amended, and that the Merger will be

 treated for financial accounting purposes as a "pooling of interests" in

 accordance with generally accepted accounting principles. In addition, the

 Merger Agreement may be terminated by Benchmarq prior to closing in the

 event that the Pre-Closing Average is less than $12.00. 


      In connection with the execution of the Merger Agreement and as an

 inducement for the Registrant to enter into the Merger Agreement, certain

 stockholders of Benchmarq, who in the aggregate own in excess of 20% of the

 shares of Benchmarq Common Stock (the "Stockholders"), have entered in a

 Voting Agreement, dated as of March 2, 1998, pursuant to which, among other

 things, the Stockholders have agreed to vote their shares of Benchmarq

 Common Stock at a meeting of Benchmarq's stockholders in favor of approval

 of the Merger Agreement. 


      As a further inducement for the Registrant to enter into the Merger

 Agreement, Benchmarq and the Registrant have entered into a Stock Option

 Agreement, dated as of March 2, 1998 (the "Option Agreement"), pursuant to

 which Benchmarq has granted the Registrant an option to acquire up to

 955,158 shares of Benchmarq Common Stock at an exercise price of $17.53 per

 share (the "Option").  The Option becomes exercisable only after the

 occurrence of certain events as described in the Option Agreement, a copy

 of which is attached to the Merger Agreement as Annex B thereto and is

 filed herewith. 


      The foregoing is qualified in its entirety by reference to the Merger

 Agreement and the Annexes thereto, and the Registrant's and Benchmarq's

 joint press release dated March 2, 1998, copies of which are attached as

 exhibits hereto and which are incorporated by reference herein. 




      On February 28, 1998, the Board of Directors of the Registrant

 rescinded its unused, prior authorization of November 11, 1997, to

 repurchase up to one million shares of Registrant Common Stock from time to
 time in the open market.   
  
  
 ITEM 7.   FINANCIAL STATEMENTS, PRO FORMA FINANCIAL INFORMATION AND
           EXHIBITS 
  
 EXHIBITS 
       
 2.1       Agreement and Plan of Merger, dated as of March 2, 1998 by and
           among Unitrode Corporation, Merrimack Corporation and BENCHMARQ
           Microelectronics, Inc., including the Annexes thereto 
  
 99.1      Joint Press Release dated March 2, 1998 
  





















































                                 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. 

  
  
                                 UNITRODE CORPORATION 
    
  

 Date: March 3, 1998             By: /s/ Robert J. Richardson       
                                   ___________________________
                                   Name:  Robert J. Richardson 
                                   Title: President and  
                                          Chief Executive Officer 
  











































  
                               EXHIBIT INDEX 
  
 Exhibit      Description  


 2.1          Agreement and Plan of Merger,
              dated as of March 2, 1998, by
              and among the Registrant,
              Merrimack Corporation and
              BENCHMARQ Microelectronics,
              Inc., including the Annexes
              thereto


 99.1         Press Release dated March 2,
              1998
[{"type": "8-K", "sequence": "1", "secsgml_size_bytes": 7431}]
{"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": "98556919"}, "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 
  
  
                              February 28, 1998          
                     (Date of earliest event reported) 
  
  
                             UNITRODE CORPORATION            
           (Exact name of Registrant as specified in its charter) 
  
  
  Maryland                    1-5609             04-2271186
 (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 March 2, 1998, Unitrode Corporation (the "Registrant") entered into

 an Agreement and Plan of Merger (the "Merger Agreement"), by and among the
 Registrant, Merrimack Corporation, a Delaware 
corporation and wholly owned 
 subsidiary of the Registrant ("Newco"), and 
BENCHMARQ Microelectronics, Inc.,
 a Delaware corporation ("Benchmarq"). 
 Pursuant to the Merger Agreement,
 among other things, Newco will be merged 
with and into Benchmarq (the 
 "Merger") and Benchmarq will become a wholly 
owned subsidiary of the
 Registrant.  At the effective time of the Merger, 
each share of Benchmarq's
 common stock, par value $.001 per share 
("Benchmarq Common Stock"), shall
 be cancelled and extinguished and 
converted into the right to receive one 
 share of the Registrant's common 
stock, par value $.01 per share ("Registrant
 Common Stock"), and the 
associated preferred stock purchase right, subject
 to adjustment as
 described below (the "Exchange Ratio").  In the event that
 the average of 
the mean high and low per share trading prices as reported in
 The Wall 
Street Journal for the New York Stock Exchange, Inc. Composite 
 Transactions 
for the twenty trading days ending on the tenth day prior to 
 the Benchmarq 
stockholders' meeting (the "Pre-Closing Average") is less than
 $16.00, the 
Exchange Ratio will be adjusted so that each share of Benchmarq
 Common
 Stock will be converted into the right to receive a number of shares of

 Registrant Common Stock equal to the quotient obtained by dividing $16.00

 by the Pre-Closing Average, provided, however, that the Exchange Ratio

 shall in no event be higher than 1.33.  In the event that the Pre-Closing

 Average is greater than $24.00, then the Exchange Ratio shall be adjusted

 so that each share of Benchmarq Common Stock will be converted into the

 right to receive a number of shares of Registrant Common Stock equal to the

 quotient obtained by dividing $24.00 by the Pre-Closing Average. In

 addition to the approval of the Merger Agreement by Benchmarq's

 stockholders, the Merger is subject to, among other things, the approval of

 the issuance of the shares of Registrant Common Stock in the Merger by the

 stockholders of the Registrant and other customary closing conditions

 including expiration of the applicable waiting period under the Hart-Scott-

 Rodino Antitrust Improvements Act of 1976, as amended. It is also a

 condition to closing that the parties receive assurances that the Merger

 will constitute a reorganization within the meaning of Section 368(a) of

 the Internal Revenue Code of 1986, as amended, and that the Merger will be

 treated for financial accounting purposes as a "pooling of interests" in

 accordance with generally accepted accounting principles. In addition, the

 Merger Agreement may be terminated by Benchmarq prior to closing in the

 event that the Pre-Closing Average is less than $12.00. 

      In connection with the execution of the Merger Agreement and as an

 inducement for the Registrant to enter into the Merger Agreement, certain

 stockholders of Benchmarq, who in the aggregate own in excess of 20% of the

 shares of Benchmarq Common Stock (the "Stockholders"), have entered in a

 Voting Agreement, dated as of March 2, 1998, pursuant to which, among other

 things, the Stockholders have agreed to vote their shares of Benchmarq

 Common Stock at a meeting of Benchmarq's stockholders in favor of approval

 of the Merger Agreement. 

      As a further inducement for the Registrant to enter into the Merger

 Agreement, Benchmarq and the Registrant have entered into a Stock Option

 Agreement, dated as of March 2, 1998 (the "Option Agreement"), pursuant to

 which Benchmarq has granted the Registrant an option to acquire up to

 955,158 shares of Benchmarq Common Stock at an exercise price of $17.53 per

 share (the "Option").  The Option becomes exercisable only after the

 occurrence of certain events as described in the Option Agreement, a copy

 of which is attached to the Merger Agreement as Annex B thereto and is

 filed herewith. 

      The foregoing is qualified in its entirety by reference to the Merger

 Agreement and the Annexes thereto, and the Registrant's and Benchmarq's

 joint press release dated March 2, 1998, copies of which are attached as

 exhibits hereto and which are incorporated by reference herein. 

      On February 28, 1998, the Board of Directors of the Registrant

 rescinded its unused, prior authorization of November 11, 1997, to

 repurchase up to one million shares of Registrant Common Stock from time to
 time in the open market.   
  
  
 ITEM 7.   FINANCIAL STATEMENTS, PRO FORMA FINANCIAL INFORMATION AND
           EXHIBITS 
  
 EXHIBITS 
       
 2.1       Agreement and Plan of Merger, dated as of March 2, 1998 by and
           among Unitrode Corporation, Merrimack Corporation and BENCHMARQ
           Microelectronics, Inc., including the Annexes thereto 
  
 99.1      Joint Press Release dated March 2, 1998 
  

                                 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. 

  
  
                                 UNITRODE CORPORATION 
    
  

 Date: March 3, 1998             By: /s/ Robert J. Richardson       
                                   ___________________________
                                   Name:  Robert J. Richardson 
                                   Title: President and  
                                          Chief Executive Officer 
  

  
                               EXHIBIT INDEX 
  
 Exhibit      Description  

 2.1          Agreement and Plan of Merger,
              dated as of March 2, 1998, by
              and among the Registrant,
              Merrimack Corporation and
              BENCHMARQ Microelectronics,
              Inc., including the Annexes
              thereto

 99.1         Press Release dated March 2,
              1998