<PAGE>   1






   AS FILED WITH THE SECURITIES AND EXCHANGE COMMISSION ON SEPTEMBER 10, 1997

                                                   REGISTRATION NO. 333-________
================================================================================


                       SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549

                                    FORM S-8

                             REGISTRATION STATEMENT
                                     UNDER
                           THE SECURITIES ACT OF 1933

                              UNITRODE CORPORATION
             (Exact Name of Registrant as Specified in its Charter)

        MARYLAND                                        04-2271186
(State or other jurisdiction                (I.R.S. Employer Identification No.)
of incorporation or organization)


                            7 CONTINENTAL BOULEVARD
                        MERRIMACK, NEW HAMPSHIRE  03054
              (Address of principal executive offices) (Zip Code)

                              UNITRODE CORPORATION
                        1992 EMPLOYEE STOCK OPTION PLAN
                            (Full Title of the Plan)

                                ROBERT L. GABLE
                CHAIRMAN, PRESIDENT AND CHIEF EXECUTIVE OFFICER
                              UNITRODE CORPORATION
                            7 CONTINENTAL BOULEVARD
                        MERRIMACK, NEW HAMPSHIRE  03054
                                 (603) 424-2410
 (Name, address and telephone number, including area code, of agent for service)

                                    Copy to:
                          JAMES J. HANKS, JR., ESQUIRE
                       BALLARD SPAHR ANDREWS & INGERSOLL
                      300 EAST LOMBARD STREET, SUITE 1900
                              BALTIMORE, MD  21202
                                (410) 528-5600  

                        CALCULATION OF REGISTRATION FEE


<TABLE>
<CAPTION>
                                AMOUNT          PROPOSED MAXIMUM     PROPOSED MAXIMUM          AMOUNT OF
   TITLE OF SECURITIES          TO BE            OFFERING PRICE     AGGREGATE OFFERING         REGISTRANT
    TO BE REGISTERED          REGISTERED         PER SHARE (1)             PRICE                  FEE
                                                                                                     
 <S>                       <C>                    <C>                  <C>                      <C>
 Common Stock              1,000,000 shares       $ 82.34              $ 82,340,000             $ 25,000
 ($.20 par value per
 share)
</TABLE>


                                                                         
   (1)             Estimated solely for the purpose of determining the    
   registration fee pursuant to Rule 457(c) and (h).  The proposed        
   maximum offering price per share is based upon the average of the      
   high and low prices for shares of Common Stock of the Registrant on    
   the New York Stock Exchange on September 9, 1997.

================================================================================


<PAGE>   2

           STATEMENT PURSUANT TO GENERAL INSTRUCTION E TO FORM S-8

   Pursuant to General Instruction E to Form S-8, the contents of Registrant's
earlier Registration Statement on Form S-8, File No. 33-62685, filed with the
Securities and Exchange Commission on September 15, 1995, are hereby
incorporated by reference.





<PAGE>   3
                                    PART II

               INFORMATION REQUIRED IN THE REGISTRATION STATEMENT

ITEM 6.  INDEMNIFICATION OF DIRECTORS AND OFFICERS

        The MGCL permits a Maryland corporation to include in its charter a
provision limiting the liability of its directors and officers to the
corporation and its stockholders for money damages except for liability
resulting from (a) actual receipt of an improper benefit or profit in money,
property or services or (b) active and deliberate dishonesty established by a
final judgment as being material to the cause of action.  The charter of
Unitrode Corporation, a Maryland corporation (the "Company"), contains such a
provision which eliminates such liability to the maximum extent permitted by
the MGCL.

        The Bylaws of the Company obligate it, to the maximum extent permitted
by Maryland law, to indemnify and to pay or reimburse reasonable expenses in
advance of final disposition of a proceeding to (a) any present or former
director or officer who is made a party to the proceeding by reason of his
service in that capacity or (b) any individual who, while a director of the
Company and at the request of the Company, serves or has served another
corporation, partnership, joint venture, trust, employee benefit plan or any
other enterprise as a director, officer, partner or trustee of such
corporation, partnership, joint venture, trust, employee benefit plan or other
enterprise and who is made a party to the proceeding by reason of his service
in that capacity.  The Bylaws also permit the Company, with the approval of the
Board of Directors of the Company, to indemnify and advance expenses to any
person who served a predecessor of the Company in any of the capacities
described above and to any employee or agent of the Company or a predecessor of
the Company.

        The MGCL requires a corporation (unless its charter provides otherwise,
which the Company's charter does not) to indemnify a director or officer who
has been successful, on the merits or otherwise, in the defense of any
proceeding to which he is made a party by reason of his service in that
capacity.  The MGCL permits a corporation to indemnify its present and former
directors and officers, among others, against judgments, penalties, fines,
settlements and reasonable expenses actually incurred by them in connection
with any proceeding to which they may be made a party by reason of their
service in those or other capacities unless it is established that (a) the act
or omission of the director or officer was material to the matter giving rise
to the proceeding and (i) was committed in bad faith or (ii) was the result of
active and deliberate dishonesty, (b) the director or officer actually received
an improper personal benefit in money, property or services or (c) in the case
of any criminal proceeding, the director or officer had reasonable cause to
believe that the act or omission was unlawful.  However, under the MGCL, a
Maryland corporation may not indemnify for an adverse judgment in a suit by or
in the right of the corporation or for a judgment of liability on the basis
that personal benefit was improperly received, unless in either case a court
orders indemnification and then only for expenses.  In addition, the MGCL
permits a corporation to advance reasonable expenses to a director or officer
upon the corporation's receipt of (a) a written affirmation by the director or
officer of his good faith belief that he has met the standard of conduct
necessary for indemnification by the

                                    - 1 -
<PAGE>   4

corporation and (b) a written statement by or on his behalf to repay the amount
paid or reimbursed by the corporation if it shall ultimately be determined that
the standard of conduct was not met.

ITEM 8.  EXHIBITS

4.1    Articles of Restatement of the Charter of the Registrant and Articles
       of Amendment to the Charter of the Registrant, previously filed as
       Exhibit 3A to the Registrant's Annual Report on Form 10-K for the fiscal
       year ended January 31, 1989 and incorporated herein by reference.

4.2    Articles Supplementary to the Charter of the Registrant, previously
       filed as Exhibits 3(A)(1) and (6) to the Registrant's Current Report on
       Form 8-K filed May 4, 1990 and incorporated herein by reference.

4.3    Articles of Amendment to the Charter of the Registrant, previously
       filed as Exhibit 3B to the Registrant's Annual Report on Form 10-K for
       the fiscal year ended January 31, 1992 and incorporated herein by
       reference.

4.4    By-Laws of the Registrant, previously filed as Exhibit 3C to the
       Registrant's Annual Report on Form 10-K filed for the fiscal year ended
       January 31, 1992 and incorporated herein by reference.

4.5    Unitrode Corporation 1992 Employee Stock Option Plan, filed as Exhibit
       4 to the Registrant's Registration Statement on Form S-8 (Registration
       No. 33-54542) and incorporated herein by reference.

4.6    Amendment No. 1 to the Unitrode Corporation 1992 Employee Stock Option
       Plan, filed as Exhibit 4.5 to the Registrant's Registration Statement on
       Form S-8 (Registration No. 33-62685) and incorporated herein by
       reference.

4.7    Amendment No. 2 to the Unitrode Corporation 1992 Employee Stock Option
       Plan.

5.1    Opinion of Ballard Spahr Andrews & Ingersoll.

23.1   Consent of Coopers & Lybrand L.L.P.

23.2   Consent of Ballard Spahr Andrews & Ingersoll (included in Exhibit 5.1).

24.1   Powers of Attorney (included on page 3 hereof).




                                      
                                    - 2 -
<PAGE>   5

                                   SIGNATURES

 Pursuant to the requirements of the Securities Act of 1933, the Registrant
certifies that it has reasonable grounds to believe that it meets all of the
requirements for filing on Form S-8 and has duly caused this Registration
Statement to be signed on its behalf by the undersigned, thereunto duly
authorized, in the City of Merrimack, State of New Hampshire, on this 9th day
of September, 1997.

                                     Unitrode Corporation, a Maryland
                                     corporation (Registrant)


                                     By: /s/ Robert L. Gable     
                                         ------------------------------------
                                         Robert L. Gable, Chairman,
                                         President and Chief Executive Officer


         KNOW ALL PERSONS BY THESE PRESENTS, that each person whose signature
appears below constitutes and appoints Robert L. Gable and Allan R. Campbell,
jointly and severally, his true and lawful attorneys-in-fact, each with full
power of substitution and resubstitution, for him and in his name, place and
stead, in any and all capacities, to sign any amendments and supplements to
this Registration Statement (including post-effective amendments), and to file
the same, with all exhibits thereto and other documents in connection
therewith, with the Securities and Exchange Commission, hereby ratifying and
confirming all that each of said attorneys-in-fact, or his substitute or
substitutes, may do or cause to be done by virtue hereof.

         Pursuant to the requirements of the Securities Act of 1933, this
Registration Statement has been signed by the following persons in the
capacities and on the date indicated.

<TABLE>
<CAPTION>
              NAME                                  TITLE                                DATE
 <S>                              <C>                                         <C>
 /s/ Robert L. Gable              Chairman, President, Chief                  September 9, 1997
 -------------------------        Executive Officer and Director
 Robert L. Gable                                                 

 /s/ Cosmo S. Trapani             Executive Vice President                    September 9, 1997
 -------------------------        and Chief Financial Officer
 Cosmo S. Trapani                                              

 /s/ Peter A. Brooke              Director                                    September 9, 1997
 -------------------------                                                                      
 Peter A. Brooke

 /s/ Edward H. Browder            Director                                    September 9, 1997
 -------------------------                                                                      
 Edward H. Browder

 /s/ Kenneth Hecht                Director                                    September 9, 1997
 -------------------------                                                                      
 Kenneth Hecht

 /s/ Louis E. Lataif              Director                                    September 9, 1997
 -------------------------                                                                      
 Louis E. Lataif

 /s/ James T. Vanderslice         Director                                    September 9, 1997
 -------------------------                                                                      
 James T. Vanderslice
</TABLE>





                                    - 3 -
<PAGE>   6

                                 EXHIBIT INDEX

<TABLE>
<CAPTION>
EXHIBIT
  NO.                                      DESCRIPTION OF EXHIBIT
<S>          <C>
4.1          Articles of Restatement of the Charter of the Registrant and Articles of Amendment to the Charter of the Registrant,
             previously filed as Exhibit 3A to the Registrant's Annual Report on Form 10-K for the fiscal year ended January 31,
             1989 and incorporated herein by reference.

4.2          Articles Supplementary to the Charter of the Registrant, previously filed as Exhibits 3(A)(1) and (6) to the
             Registrant's Current Report on Form 8-K filed May 4, 1990 and incorporated herein by reference.

4.3          Articles of Amendment to the Charter of the Registrant, previously filed as Exhibit 3B to the Registrant's Annual
             Report on Form 10-K for the fiscal year ended January 31, 1992 and incorporated herein by reference.

4.4          By-Laws of the Registrant, previously filed as Exhibit 3C to the Registrant's Annual Report on Form 10-K filed for
             the fiscal year ended January 31, 1992 and incorporated herein by reference.

4.5          Unitrode Corporation 1992 Employee Stock Option Plan, filed as Exhibit 4 to the Registrant's Registration Statement
             on Form S-8 (Registration No. 33-54542) and incorporated herein by reference.

4.6          Amendment No. 1 to the Unitrode Corporation 1992 Employee Stock Option Plan, filed as Exhibit 4.5 to the
             Registrant's Registration Statement on Form S-8 (Registration No. 33-62685) and incorporated herein by reference.

4.7          Amendment No. 2 to the Unitrode Corporation 1992 Employee Stock Option Plan.

5.1          Opinion of Ballard Spahr Andrews & Ingersoll.

23.1         Consent of Coopers & Lybrand L.L.P.

23.2         Consent of Ballard Spahr Andrews & Ingersoll (included in Exhibit 5.1).

24.1         Powers of Attorney (included on page 3 hereof).

</TABLE>




                                                     - 5 -
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{"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": "S-8", "file-number": "333-35339", "film-number": "97678616"}, "business-address": {"street1": "7 CONTINENTAL BLVD", "city": "MERRIMACK", "state": "NH", "zip": "03054", "phone": "6034298770"}, "mail-address": {"street1": "7 CONTINENTAL BLVD", "city": "MERRIMACK", "state": "NH", "zip": "03054"}}
1

   AS FILED WITH THE SECURITIES AND EXCHANGE COMMISSION ON SEPTEMBER 10, 1997

                                                   REGISTRATION NO. 333-________
================================================================================

                       SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549

                                    FORM S-8

                             REGISTRATION STATEMENT
                                     UNDER
                           THE SECURITIES ACT OF 1933

                              UNITRODE CORPORATION
             (Exact Name of Registrant as Specified in its Charter)

        MARYLAND                                        04-2271186
(State or other jurisdiction                (I.R.S. Employer Identification No.)
of incorporation or organization)

                            7 CONTINENTAL BOULEVARD
                        MERRIMACK, NEW HAMPSHIRE  03054
              (Address of principal executive offices) (Zip Code)

                              UNITRODE CORPORATION
                        1992 EMPLOYEE STOCK OPTION PLAN
                            (Full Title of the Plan)

                                ROBERT L. GABLE
                CHAIRMAN, PRESIDENT AND CHIEF EXECUTIVE OFFICER
                              UNITRODE CORPORATION
                            7 CONTINENTAL BOULEVARD
                        MERRIMACK, NEW HAMPSHIRE  03054
                                 (603) 424-2410
 (Name, address and telephone number, including area code, of agent for service)

                                    Copy to:
                          JAMES J. HANKS, JR., ESQUIRE
                       BALLARD SPAHR ANDREWS & INGERSOLL
                      300 EAST LOMBARD STREET, SUITE 1900
                              BALTIMORE, MD  21202
                                (410) 528-5600  

                        CALCULATION OF REGISTRATION FEE
AMOUNT          PROPOSED MAXIMUM     PROPOSED MAXIMUM          AMOUNT OF
   TITLE OF SECURITIES          TO BE            OFFERING PRICE     AGGREGATE OFFERING         REGISTRANT
    TO BE REGISTERED          REGISTERED         PER SHARE (1)             PRICE                  FEE
Common Stock              1,000,000 shares       $ 82.34              $ 82,340,000             $ 25,000
 ($.20 par value per
 share)
(1)             Estimated solely for the purpose of determining the    
   registration fee pursuant to Rule 457(c) and (h).  The proposed        
   maximum offering price per share is based upon the average of the      
   high and low prices for shares of Common Stock of the Registrant on    
   the New York Stock Exchange on September 9, 1997.

================================================================================
2

           STATEMENT PURSUANT TO GENERAL INSTRUCTION E TO FORM S-8

   Pursuant to General Instruction E to Form S-8, the contents of Registrant's
earlier Registration Statement on Form S-8, File No. 33-62685, filed with the
Securities and Exchange Commission on September 15, 1995, are hereby
incorporated by reference.
3
                                    PART II

               INFORMATION REQUIRED IN THE REGISTRATION STATEMENT

ITEM 6.  INDEMNIFICATION OF DIRECTORS AND OFFICERS

        The MGCL permits a Maryland corporation to include in its charter a
provision limiting the liability of its directors and officers to the
corporation and its stockholders for money damages except for liability
resulting from (a) actual receipt of an improper benefit or profit in money,
property or services or (b) active and deliberate dishonesty established by a
final judgment as being material to the cause of action.  The charter of
Unitrode Corporation, a Maryland corporation (the "Company"), contains such a
provision which eliminates such liability to the maximum extent permitted by
the MGCL.

        The Bylaws of the Company obligate it, to the maximum extent permitted
by Maryland law, to indemnify and to pay or reimburse reasonable expenses in
advance of final disposition of a proceeding to (a) any present or former
director or officer who is made a party to the proceeding by reason of his
service in that capacity or (b) any individual who, while a director of the
Company and at the request of the Company, serves or has served another
corporation, partnership, joint venture, trust, employee benefit plan or any
other enterprise as a director, officer, partner or trustee of such
corporation, partnership, joint venture, trust, employee benefit plan or other
enterprise and who is made a party to the proceeding by reason of his service
in that capacity.  The Bylaws also permit the Company, with the approval of the
Board of Directors of the Company, to indemnify and advance expenses to any
person who served a predecessor of the Company in any of the capacities
described above and to any employee or agent of the Company or a predecessor of
the Company.

        The MGCL requires a corporation (unless its charter provides otherwise,
which the Company's charter does not) to indemnify a director or officer who
has been successful, on the merits or otherwise, in the defense of any
proceeding to which he is made a party by reason of his service in that
capacity.  The MGCL permits a corporation to indemnify its present and former
directors and officers, among others, against judgments, penalties, fines,
settlements and reasonable expenses actually incurred by them in connection
with any proceeding to which they may be made a party by reason of their
service in those or other capacities unless it is established that (a) the act
or omission of the director or officer was material to the matter giving rise
to the proceeding and (i) was committed in bad faith or (ii) was the result of
active and deliberate dishonesty, (b) the director or officer actually received
an improper personal benefit in money, property or services or (c) in the case
of any criminal proceeding, the director or officer had reasonable cause to
believe that the act or omission was unlawful.  However, under the MGCL, a
Maryland corporation may not indemnify for an adverse judgment in a suit by or
in the right of the corporation or for a judgment of liability on the basis
that personal benefit was improperly received, unless in either case a court
orders indemnification and then only for expenses.  In addition, the MGCL
permits a corporation to advance reasonable expenses to a director or officer
upon the corporation's receipt of (a) a written affirmation by the director or
officer of his good faith belief that he has met the standard of conduct
necessary for indemnification by the

                                    - 1 -
4

corporation and (b) a written statement by or on his behalf to repay the amount
paid or reimbursed by the corporation if it shall ultimately be determined that
the standard of conduct was not met.

ITEM 8.  EXHIBITS

4.1    Articles of Restatement of the Charter of the Registrant and Articles
       of Amendment to the Charter of the Registrant, previously filed as
       Exhibit 3A to the Registrant's Annual Report on Form 10-K for the fiscal
       year ended January 31, 1989 and incorporated herein by reference.

4.2    Articles Supplementary to the Charter of the Registrant, previously
       filed as Exhibits 3(A)(1) and (6) to the Registrant's Current Report on
       Form 8-K filed May 4, 1990 and incorporated herein by reference.

4.3    Articles of Amendment to the Charter of the Registrant, previously
       filed as Exhibit 3B to the Registrant's Annual Report on Form 10-K for
       the fiscal year ended January 31, 1992 and incorporated herein by
       reference.

4.4    By-Laws of the Registrant, previously filed as Exhibit 3C to the
       Registrant's Annual Report on Form 10-K filed for the fiscal year ended
       January 31, 1992 and incorporated herein by reference.

4.5    Unitrode Corporation 1992 Employee Stock Option Plan, filed as Exhibit
       4 to the Registrant's Registration Statement on Form S-8 (Registration
       No. 33-54542) and incorporated herein by reference.

4.6    Amendment No. 1 to the Unitrode Corporation 1992 Employee Stock Option
       Plan, filed as Exhibit 4.5 to the Registrant's Registration Statement on
       Form S-8 (Registration No. 33-62685) and incorporated herein by
       reference.

4.7    Amendment No. 2 to the Unitrode Corporation 1992 Employee Stock Option
       Plan.

5.1    Opinion of Ballard Spahr Andrews & Ingersoll.

23.1   Consent of Coopers & Lybrand L.L.P.

23.2   Consent of Ballard Spahr Andrews & Ingersoll (included in Exhibit 5.1).

24.1   Powers of Attorney (included on page 3 hereof).

                                      
                                    - 2 -
5

                                   SIGNATURES

 Pursuant to the requirements of the Securities Act of 1933, the Registrant
certifies that it has reasonable grounds to believe that it meets all of the
requirements for filing on Form S-8 and has duly caused this Registration
Statement to be signed on its behalf by the undersigned, thereunto duly
authorized, in the City of Merrimack, State of New Hampshire, on this 9th day
of September, 1997.

                                     Unitrode Corporation, a Maryland
                                     corporation (Registrant)

                                     By: /s/ Robert L. Gable     
                                         ------------------------------------
                                         Robert L. Gable, Chairman,
                                         President and Chief Executive Officer

         KNOW ALL PERSONS BY THESE PRESENTS, that each person whose signature
appears below constitutes and appoints Robert L. Gable and Allan R. Campbell,
jointly and severally, his true and lawful attorneys-in-fact, each with full
power of substitution and resubstitution, for him and in his name, place and
stead, in any and all capacities, to sign any amendments and supplements to
this Registration Statement (including post-effective amendments), and to file
the same, with all exhibits thereto and other documents in connection
therewith, with the Securities and Exchange Commission, hereby ratifying and
confirming all that each of said attorneys-in-fact, or his substitute or
substitutes, may do or cause to be done by virtue hereof.

         Pursuant to the requirements of the Securities Act of 1933, this
Registration Statement has been signed by the following persons in the
capacities and on the date indicated.
NAME                                  TITLE                                DATE
/s/ Robert L. Gable              Chairman, President, Chief                  September 9, 1997
 -------------------------        Executive Officer and Director
 Robert L. Gable                                                 

 /s/ Cosmo S. Trapani             Executive Vice President                    September 9, 1997
 -------------------------        and Chief Financial Officer
 Cosmo S. Trapani                                              

 /s/ Peter A. Brooke              Director                                    September 9, 1997
 -------------------------                                                                      
 Peter A. Brooke

 /s/ Edward H. Browder            Director                                    September 9, 1997
 -------------------------                                                                      
 Edward H. Browder

 /s/ Kenneth Hecht                Director                                    September 9, 1997
 -------------------------                                                                      
 Kenneth Hecht

 /s/ Louis E. Lataif              Director                                    September 9, 1997
 -------------------------                                                                      
 Louis E. Lataif

 /s/ James T. Vanderslice         Director                                    September 9, 1997
 -------------------------                                                                      
 James T. Vanderslice
- 3 -
6

                                 EXHIBIT INDEX
EXHIBIT
  NO.                                      DESCRIPTION OF EXHIBIT
4.1          Articles of Restatement of the Charter of the Registrant and Articles of Amendment to the Charter of the Registrant,
             previously filed as Exhibit 3A to the Registrant's Annual Report on Form 10-K for the fiscal year ended January 31,
             1989 and incorporated herein by reference.

4.2          Articles Supplementary to the Charter of the Registrant, previously filed as Exhibits 3(A)(1) and (6) to the
             Registrant's Current Report on Form 8-K filed May 4, 1990 and incorporated herein by reference.

4.3          Articles of Amendment to the Charter of the Registrant, previously filed as Exhibit 3B to the Registrant's Annual
             Report on Form 10-K for the fiscal year ended January 31, 1992 and incorporated herein by reference.

4.4          By-Laws of the Registrant, previously filed as Exhibit 3C to the Registrant's Annual Report on Form 10-K filed for
             the fiscal year ended January 31, 1992 and incorporated herein by reference.

4.5          Unitrode Corporation 1992 Employee Stock Option Plan, filed as Exhibit 4 to the Registrant's Registration Statement
             on Form S-8 (Registration No. 33-54542) and incorporated herein by reference.

4.6          Amendment No. 1 to the Unitrode Corporation 1992 Employee Stock Option Plan, filed as Exhibit 4.5 to the
             Registrant's Registration Statement on Form S-8 (Registration No. 33-62685) and incorporated herein by reference.

4.7          Amendment No. 2 to the Unitrode Corporation 1992 Employee Stock Option Plan.

5.1          Opinion of Ballard Spahr Andrews & Ingersoll.

23.1         Consent of Coopers & Lybrand L.L.P.

23.2         Consent of Ballard Spahr Andrews & Ingersoll (included in Exhibit 5.1).

24.1         Powers of Attorney (included on page 3 hereof).
- 5 -