<PAGE>   1

                UNITED STATES SECURITIES AND EXCHANGE COMMISSION
                              WASHINGTON D.C. 20549

                                    FORM 10-Q


(Mark One)
[X]  QUARTERLY REPORT PURSUANT TO SECTION 13 or 15(d) OF THE SECURITIES
     EXCHANGE ACT OF 1934

                   For the quarterly period ended MAY 2, 1998

                                       OR

[ ]  TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES
     EXCHANGE ACT OF 1934
     
                For the transition period from _______ to _______


                          Commission file number 1-5609


                              UNITRODE CORPORATION
             (Exact name of registrant as specified in its charter)


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

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

       Registrant's telephone number, including area code: (603) 424-2410


Indicate by check mark whether the registrant (1) has filed all reports required
to be filed by Section 13 or 15(d) of Securities Exchange Act of 1934 during the
preceding 12 months (or for such shorter period that the registrant was required
to file such reports), and (2) has been subject to such filing requirements for
the past 90 days.  Yes [X]  No [ ]

There were 24,408,357 shares of common stock outstanding as of May 2, 1998.













                                       -1-

<PAGE>   2

                          PART I. FINANCIAL INFORMATION

Item 1. Financial Statements


               Unitrode Corporation and Consolidated Subsidiaries
                                 Balance Sheets
                        (in thousands except share data)

<TABLE>
<CAPTION>

                                                May 2, 1998     January 31, 1998
Assets                                          (Unaudited)
--------------------------------------------------------------------------------
<S>                                               <C>               <C>

Current assets:
  Cash and cash equivalents                       $ 57,263          $ 65,074
  Accounts receivable, net of allowance
     of $460 in May, 1998
     and $460 in January, 1998                      19,011            24,507
  Notes receivable                                     714               709
  Inventories:
     Raw materials                                     961             1,276
     Work in process                                 8,594             8,774
     Finished goods                                  4,531             2,992
                                                  --------          --------
       Total inventories                            14,086            13,042
                                                  --------          --------

  Deferred income taxes                              6,724             7,886
  Prepaid expenses and other
    current assets                                   2,553             2,373
                                                  --------          --------

     Total current assets                          100,351           113,591
                                                  --------          --------

Property, plant and equipment, at cost             138,697           140,568
  Less accumulated depreciation                     62,546            62,403
                                                  --------          --------
    Property, plant and equipment, net              76,151            78,165
                                                  --------          --------

Notes and other receivables, net
  of discount                                        2,638             2,828
Deferred income taxes                                   --               324
Restricted cash and investments                      1,172             1,180
Excess of cost over net assets acquired,
   net of accumulated amortization of
   $2,465 in May, 1998 and
   $2,394 in January, 1998                           1,625             1,696
Other assets and deferred charges,net                1,757             4,255
                                                  --------          --------

Total assets                                      $183,694          $202,039
                                                  ========          ========


</TABLE>






The accompanying notes are an integral part of the financial statements.



                                       -2-

<PAGE>   3

               Unitrode Corporation and Consolidated Subsidiaries
                                 Balance Sheets
                        (in thousands except share data)


<TABLE>
<CAPTION>

                                                   May 2, 1998  January 31, 1998
Liabilities and Stockholders' Equity               (Unaudited)
--------------------------------------------------------------------------------
<S>                                                   <C>               <C>     

Current liabilities:
  Accounts payable                                    $ 10,383          $ 14,231
  Income taxes payable                                     721             3,944
  Accrued employee compensation and benefits             1,994            10,916
  Accrued distributor liability                          2,867             3,291
  Other current liabilities                              6,327             7,373
                                                      --------          --------

     Total current liabilities                          22,292            39,755
                                                      --------          --------

Deferred income taxes                                    2,119             1,791
Other long-term liabilities                                900             1,131
                                                      --------          --------

     Total liabilities                                  25,311            42,677
                                                      --------          --------

Stockholders' equity:
  Common stock,$.01 par value:
    Authorized - 60,000,000 shares
    Issued - 24,408,357 in May, 1998 and
             24,310,682 in January, 1998                   244               243
  Additional paid-in capital                            46,326            45,089
  Retained earnings                                    112,814           115,163
                                                      --------          --------
                                                       159,384           160,495

  Less: Deferred compensation                            1,001             1,133
                                                      --------          --------

     Total stockholders' equity                        158,383           159,362
                                                      --------          --------

Total liabilities and
    stockholders' equity                              $183,694          $202,039
                                                      ========          ========


</TABLE>










The accompanying notes are an integral part of the financial statements.


                                       -3-

<PAGE>   4

               Unitrode Corporation and Consolidated Subsidiaries
                            Statements of Operations
                                   (Unaudited)
                        (in thousands except share data)


<TABLE>
<CAPTION>

For the three months ended                   May 2, 1998       May 3, 1997
--------------------------------------------------------------------------
<S>                                            <C>                <C>    

Net revenues                                   $ 28,019           $40,840
Cost of revenues                                 17,583            19,146
                                             ----------        ----------

  Gross profit                                   10,436            21,694
                                             ----------        ----------

Operating expenses:
  Research and development expenses               3,793             4,322
  Selling, general and administrative
    expenses                                      5,563             6,727
  New fab pre-operating expenses                  1,109             1,514
  Restructuring and merger costs                  2,033                --
                                             ----------        ----------

    Total operating expenses                     12,498            12,563
                                             ----------        ----------

Income (loss) from operations                    (2,062)            9,131
                                             ----------        ----------

Other income (expense):
  Royalty income                                    558               603
  Non-operating income (expense), net            (2,632)              175
  Interest income, net                              829               611
                                             ----------        ----------

    Total other income (expense)                 (1,245)            1,389
                                             ----------        ----------

Income (loss) before income tax
  provision (benefit)                            (3,307)           10,520

Income tax provision (benefit)                     (958)            3,934
                                             ----------        ----------

Net income (loss)                            $   (2,349)       $    6,586
                                             ==========        ==========




Earnings per common share:
    Basic                                    $     (.10)       $      .28
                                             ==========        ==========
    Diluted                                  $     (.10)       $      .27
                                             ==========        ==========

Average common and common equivalent 
  shares outstanding:
    Basic                                    24,336,107        23,356,738
                                             ==========        ==========
    Diluted                                  24,336,107        24,389,716
                                             ==========        ==========


</TABLE>




The accompanying notes are an integral part of the financial statements.


                                       -4-



<PAGE>   5

               Unitrode Corporation and Consolidated Subsidiaries
                            Statements of Cash Flows
                                   (Unaudited)
                                 (in thousands)

<TABLE>
<CAPTION>

For the three months ended                                     May 2, 1998      May 3, 1997
-------------------------------------------------------------------------------------------
<S>                                                              <C>               <C>     

Cash flows from operating activities:
   Net income (loss)                                             $(2,349)          $  6,586
   Adjustments to reconcile net income (loss) to
   net cash provided (used) by operating activities:
     Depreciation and amortization                                 2,894              2,759
     Deferred compensation                                           132                 24
     Writedown of assets                                           5,615                 --
     Deferred income taxes                                         1,814               (364)
     Other, net                                                       18                 (2)
    (Increase) decrease in assets:
       Accounts receivable                                         5,496             (9,380)
       Inventories                                                (3,494)              (261)
       Other current and long-term assets                            (98)               162
     Increase (decrease) in liabilities:
       Accounts payable                                           (3,848)             6,678
       Income taxes payable                                       (3,223)             4,239
       Accrued employee compensation and benefits                 (8,922)               787
       Accrued distributor liability                                (424)               (42)
       Other current and long-term liabilities                    (1,277)             2,472
                                                                 -------           --------
         Total adjustments                                        (5,317)             7,072
                                                                 -------           --------
     Net cash provided (used) by operating activities             (7,666)            13,658
                                                                 -------           --------
Cash flows from investing activities:
   Property, plant and equipment and deposits                     (1,610)           (15,745)
   Proceeds on sale of assets                                         27                 88
   Repayment of notes receivable                                     191                292
   Restricted cash and investments                                     9                 (5)
                                                                 -------           --------
     Net cash used by investing activities                        (1,383)           (15,370)
                                                                 -------           --------
Cash flows from financing activities:
   Proceeds from exercise of stock options and warrants            1,238                940
   Purchase of common stock                                           --               (164)
                                                                 -------           --------
     Net cash provided by financing activities                     1,238                776
                                                                 -------           --------

Net decrease in cash and cash equivalents                         (7,811)              (936)
Cash and cash equivalents at beginning of period                  65,074             52,012
                                                                 -------           --------
Cash and cash equivalents at end of period                       $57,263           $ 51,076
                                                                 =======           ========

Supplemental information:
   Interest paid                                                 $    30           $     47
   Income taxes paid, net of tax refunds                             459                 59

</TABLE>





The accompanying notes are an integral part of the financial statements.



                                       -5-
<PAGE>   6

               Unitrode Corporation and Consolidated Subsidiaries
                   Notes to Consolidated Financial Statements
                                   May 2, 1998
                                   (Unaudited)
                        (in thousands except share data)

NOTE 1 - BASIS OF PRESENTATION

The accompanying unaudited consolidated financial statements have been prepared
in accordance with generally accepted accounting principles for interim
financial information and pursuant to the rules and regulations of the
Securities and Exchange Commission. Accordingly, they do not include all of the
information and footnotes required by generally accepted accounting principles
for complete financial statements. For further information, refer to the
consolidated financial statements and footnotes included in the annual report on
Form 10-K of Unitrode Corporation (the "Company") for the year ended January 31,
1998.

In the opinion of management, all adjustments considered necessary for a fair
presentation have been included. Operating results for the three-month period
ended May 2, 1998 are not necessarily indicative of the results that may be
expected for the year ending January 31, 1999. Certain amounts for fiscal year
1998 have been reclassified to conform with presentation of similar amounts in
fiscal year 1999.

NOTE 2 - NEW ACCOUNTING STANDARDS

Effective February 1, 1998, the Company adopted Statement of Financial
Accounting Standards ("SFAS") No. 130, "Reporting Comprehensive Income." SFAS
No. 130 requires disclosure of comprehensive income in interim periods and
additional disclosures of the components of comprehensive income on an annual
basis. Comprehensive income includes all changes in equity during a period
except those resulting from investments by and distributions to the Company's
shareholders. For the quarters ended May 2, 1998 and May 3, 1997, there were no
differences between the Company's comprehensive income and net income.

In June 1997, the Financial Accounting Standards Board issued Statement of
Financial Accounting Standards No. 131, "Disclosures about Segments of an
Enterprise and Related Information," which establishes annual and interim
reporting standards for an enterprise's business segments and related
disclosures about its products, services, geographic areas and major customers.
Adoption of this statement will not impact the Company's consolidated financial
position, results of operations or cash flows. The Company will adopt this
statement in its financial statements for the year ending January 31, 1999.

NOTE 3 - EARNINGS PER SHARE

The following table sets forth the computation of basic and diluted earnings per
share.

<TABLE>
<CAPTION>

Three months ended                                 May 2, 1998       May 3, 1997
--------------------------------------------------------------------------------
<S>                                                 <C>              <C>        

Net income (loss)                                   $    (2,349)     $     6,586
                                                    ===========      ===========

Basic weighted average shares outstanding            24,336,107       23,356,738
Effect of dilutive securities-stock options                  --          928,618
Effect of dilutive securities-stock warrants                 --          104,360
                                                    -----------      -----------
Diluted weighted average shares outstanding          24,336,107       24,389,716
                                                    ===========      ===========

Basic earnings (loss) per share                     $      (.10)     $       .28
                                                    ===========      ===========

Diluted earnings (loss) per share                   $      (.10)     $       .27
                                                    ===========      ===========

</TABLE>



                                       -6-



<PAGE>   7

NOTE 3 - EARNINGS PER SHARE (continued)

Options to purchase a total of 2,783,425 shares of common stock at prices
ranging from $2.38 to $40.36 were outstanding as of May 2, 1998 but not included
in the computation of diluted earnings per share because the Company reported a
net loss for this period. Included in this total were options to purchase
988,500 shares of common stock at prices ranging from $18.50 to $40.36 that
would not have been included in the computation of diluted earnings per share
because these options' exercise prices were greater than the average market
price of the common shares as of such dates and, therefore, would be
anti-dilutive under the treasury stock method.

No options to purchase shares of common stock were above the average market
price of the Company's common stock for the period ended May 3, 1997.

NOTE 4 - PROPOSED MERGER

On March 2, 1998, the Company announced that it had entered into a definitive
agreement to merge with BENCHMARQ Microelectronics, Inc. ("BENCHMARQ"). Under
the terms of the proposed transaction, BENCHMARQ stockholders would receive
between 1.00 and 1.33 shares of Unitrode Corporation common stock for each
share of BENCHMARQ common stock outstanding, based on Unitrode's pre-closing
average stock price over a twenty trading day period. As of March 31, 1998, 
BENCHMARQ had approximately 7.2 million shares issued and outstanding. The
transaction is intended to be accounted for as a "Pooling of Interests" and is
subject to several conditions, including the approval of the stockholders of
both companies. The Company's stockholders will vote on the issuance of
Unitrode stock for the proposed transaction at the Company's annual
shareholder's meeting currently scheduled for June 29, 1998. As a "Pooling of
Interests", upon completion of the transaction, the historical results of
BENCHMARQ will be combined with those of the Company.

On June 15, 1998, the Company announced that its Board of Directors had
withdrawn its recommendation that Unitrode shareholders approve the issuance of
shares of Unitrode common stock pursuant to the March 2, 1998 agreement. The
Company has not terminated the merger agreement at this time, but reserves its
rights to do so in accordance with the terms of the agreement.

NOTE 5 - NON-OPERATING INCOME (EXPENSE)

<TABLE>
<CAPTION>
         Three months ended                          May 2, 1998    May 3, 1997
         ---------------------------------------------------------------------

         <S>                                             <C>               <C> 
         Foreign exchange gains (losses)                 $  (244)          $ 30
         Gains (losses) on sale of fixed assets               (9)            33
         Net rental income                                   121            112
         Writedown of equity investments                  (2,500)            --
                                                         -------           ----
                  Total                                  $(2,632)          $175
                                                         =======           ====
</TABLE>


NOTE 6 - SPECIAL CHARGES

During the first quarter of fiscal year 1999, the Company recorded pre-tax
special charges totaling $7.1 million of which $2.6 million was charged to cost
of sales, $2.0 million was charged to restructuring and merger costs in
operating expenses, and $2.5 million was charged to other income (expense).

The charge of $2.6 million to cost of sales was for inventory writeoffs and
consisted primarily of a custom product which was manufactured in the first
quarter of fiscal year 1999 for a disk drive customer. The product did not meet
the customer's specifications and has or will be scrapped.






                                       -7-

<PAGE>   8

NOTE 6 - SPECIAL CHARGES (continued)


The $2.0 million charged to operating expenses consisted of $1.2 million for
actions intended to align the business with the forecasted level of demand in
fiscal year 1999 and $0.8 million for professional services incurred to date in
connection with the proposed merger with BENCHMARQ. Restructuring charges of
$1.2 million consisted of $0.7 million used to writedown equipment associated
with the production of 4" bipolar wafers to net realizable value and $0.5
million for severance costs associated with a workforce reduction of about 34
employees, or 5% of the total workforce. The annualized cost reduction from the
Company's restructuring is anticipated to be approximately $1.8 million.

The $2.5 million charge to other income (expense) was to account for a reduction
in the carrying value of the Company's equity investment in an outside foundry
in which the Company maintained a $2.5 million equity investment and a $1.0
million note receivable. The significant reduction in the Company's business in
the first quarter of fiscal year 1999 and the anticipated ramp-up of the
Company's 6" fab in the second half of the year has substantially reduced demand
for wafers produced at this foundry. The Company currently is the primary
customer of this foundry. The material reduction in wafer output will negatively
impact this foundry's financial condition and estimated future cash flows. The
Company did not establish a valuation allowance on its $1.0 million note
receivable as it believes that the fair market value of the foundry's tangible
assets are sufficient to recover the value of the asset.






































                                       -8-



<PAGE>   9

Item 2. Management's Discussion and Analysis of Financial Condition and Results
of Operations

RESULTS OF OPERATIONS

Three Months Ended May 2, 1998 versus Three Months Ended May 3, 1997

The following table sets forth, for the fiscal periods indicated, the percentage
of net revenues represented by certain items in Unitrode's statements of
operations:

<TABLE>
<CAPTION>
                                             Percentage of total revenues.
Quarter ended                                May 2, 1998     May 3, 1997
--------------------------------------------------------------------------
<S>                                              <C>              <C>   

Net revenues                                     100.0%           100.0%
Cost of revenues                                  62.8             46.9
                                                 -----            -----
     Gross profit                                 37.2             53.1
                                                 -----            -----
Operating expenses:
  Research & development expenses                 13.5             10.6
  Selling, general and administrative
    expenses                                      19.9             16.5
  New fab pre-operating expenses                   4.0              3.7
  Restructuring and merger costs                   7.2               --
                                                 -----            -----
     Total operating expenses                     44.6             30.8
                                                 -----            -----

Income (loss) from operations                     (7.4)            22.4
Other income (expense)                            (4.4)             3.4
                                                 -----            -----
Income (loss) before income tax
  provision (benefit)                            (11.8)            25.8
Net income (loss)                                 (8.4)%           16.1%
                                                 -----            -----

</TABLE>


Net sales for the Company's first quarter ended May 2, 1998 were $28.0 million
compared with $40.8 million in the previous year's first quarter, a decrease of
$12.8 million, or 31%. The decline was primarily due to significantly reduced
shipments to what had been the Company's largest customer, a disk drive
manufacturer. Because of delays incurred in qualifying a revised part at an
outside foundry for this customer, the Company will not ship this part and
further has decided not to compete for the next generation part, but will now
focus its design and production resources to other analog and mixed signal
products. As a result, it is expected that this customer will no longer
represent more than 10% of the Company's business.

Approximately 61% of sales in the first quarter were international compared with
68% in the prior year.

Gross profit as a percentage of net sales was 37.2% in the first quarter of
fiscal year 1999 compared to 53.1% in the same quarter of the prior year.
Excluding the special charge of $2.6 million for inventory writeoffs, gross
profit as a percentage of net sales was 46.5%. The decrease in the gross profit
percentage compared to the prior year, excluding the special charge, was
primarily as a result of reduced factory utilization due to the reduced demand
in the Company's served markets.

Weakness, primarily in the EDP market, has affected and may continue to affect
the Company's short-term bookings and the schedule of existing backlog. The
Company also believes that inventory levels at some of its customers and
distributors continues to be high and must be reduced before customers make any
significant new purchase commitments.



                                       -9-



<PAGE>   10

RESULTS OF OPERATIONS (continued)


Research and development expenses were approximately 13.5% of net sales, or $3.8
million, compared with 10.6%, or $4.3 million, in the prior year. The percentage
increase for research and development expenses was principally due to the
decreased sales volume. Selling, general and administrative expenses were 19.9%
of net sales, or $5.6 million, compared with 16.5%, or $6.7 million, in the
previous year's first quarter. The decrease of $1.2 million was primarily due to
reductions in incentive compensation accruals and sales commissions.

In the first quarter of fiscal year 1999, the Company incurred $1.1 million in
pre-operating expenses associated with the new 6" BiCMOS wafer fabrication
facility in Merrimack, New Hampshire. Pre-operating costs, which are incurred
prior to the commencement of production, relate primarily to the qualification
of equipment and manufacturing processes to meet design, test, and reliability
as well as to recruit and train personnel. The Company estimates spending a
total of $8.0 to $9.0 million in pre-operating expenses, of which $7.4 million
has been recorded to date. The balance of these expenses are expected to be
incurred in the second quarter of fiscal year 1999. The new wafer fabrication
facility is expected to become operational in July 1998.

During the first quarter of fiscal year 1999, the Company recorded special
charges totaling $7.1 million. These costs consisted of $2.6 million charged to
cost of sales for the writeoff of inventory, $2.0 million for costs associated
with realigning the business to the reduced level of demand and costs
associated with the proposed merger with BENCHMARQ, and $2.5 million charged to
other income (expense) for the reduction in the carrying value of Unitrode's
investment in an outside foundry. See Note 6 in the Company's consolidated
financial statements for further information.

The consolidated effective tax rate for the quarter ended May 2, 1998 was a
29.0% benefit compared with a 37.4% provision for the quarter ended May 3, 1997.
Excluding special charges, the effective tax rate was 37.7% in the first quarter
of fiscal year 1999.

Net income of $6.6 million, or $.27 per diluted share, in the first quarter of
fiscal year 1998 decreased to a net loss of $2.3 million, or $(.10) per diluted
share, in the first quarter of fiscal year 1999. Excluding special charges, net
income would have been $2.4 million, or $.10 per diluted share, for the first
quarter of fiscal year 1999.

FINANCIAL CONDITION

Cash and cash equivalents at May 2, 1998 decreased by $7.8 million to $57.3
million since the beginning of fiscal year 1999. The principal uses of cash were
$7.7 million for operating activities and $1.6 million in capital expenditures
offset by $1.2 million in proceeds from exercises of employee stock options.

In fiscal year 1999, the Company expects capital expenditures to total
approximately $11 to $14 million for the support of ongoing operations. It is
anticipated that the Company's operating cash needs for fiscal year 1999,
including planned capital expenditures, will be met by internally generated
funds and available cash.





                                      -10-

<PAGE>   11

FINANCIAL CONDITION (continued)

The ratio of current assets to current liabilities was 4.50:1 at May 2, 1998
compared with 2.86:1 at January 31, 1998. Working capital of $78.1 million at
May 2, 1998 increased by $4.2 million from January 31, 1998. Accounts receivable
at May 2, 1998 decreased by $5.5 million from January 31, 1998 primarily due to
the lower level of sales. Receivable day sales outstanding ("DSO") were 62 days
at May 2, 1998 compared to 50 days at January 31, 1998 and 52 days at May 3,
1997. The increase in DSO at the end of the first quarter of fiscal year 1999
was primarily caused by delay of a few days in the receipt of a significant
payment. Income taxes payable at May 2, 1998 decreased by a total of $3.2
million from January 31, 1998, primarily due to recording a tax benefit related
to the first quarter loss resulting from the special charges. Accrued employee
compensation and benefits have decreased by $8.9 million since year-end
primarily due to incentive compensation benefit payments relating to fiscal year
1998.

NEW ACCOUNTING STANDARDS

See Note 2 in the Company's consolidated financial statements for a discussion
of recently issued accounting standards.

PROPOSED MERGER

On March 2, 1998, the Company announced that it had entered into a definitive
agreement to merge with BENCHMARQ Microelectronics, Inc. ("BENCHMARQ"). Under
the terms of the proposed transaction, BENCHMARQ stockholders would receive
between 1.00 and 1.33 shares of Unitrode Corporation common stock for each
share of BENCHMARQ common stock outstanding, based on Unitrode's pre-closing
average stock price over a twenty trading day period. As of March 31, 1998, 
BENCHMARQ had approximately 7.2 million shares issued and outstanding. The
transaction is intended to be accounted for as a "Pooling of Interests" and is
subject to several conditions, including the approval of the stockholders of
both companies. The Company's stockholders will vote on the issuance of
Unitrode stock for the proposed transaction at the Company's annual
shareholder's meeting currently scheduled for June 29, 1998. As a "Pooling of
Interests", upon completion of the transaction, the historical results of
BENCHMARQ will be combined with those of the Company.

On June 15, 1998, the Company announced that its Board of Directors had
withdrawn its recommendation that Unitrode shareholders approve the issuance of
shares of Unitrode common stock pursuant to the March 2, 1998 agreement. The
Company has not terminated the merger agreement at this time, but reserves its
rights to do so in accordance with the terms of the agreement. 

FACTORS AFFECTING FUTURE RESULTS

The Company's future operating results are difficult to predict and may be
affected by a number of factors including the timely ability to develop and
market new products, competitive pricing pressures, fluctuations in
manufacturing yields, adequate availability of processed silicon wafers from
foundry sources, insufficient or excess manufacturing and testing capacity,
changes in product mix, and fluctuating economic conditions in the United
States, Asia and international markets.

Sales to one customer, IBM Corporation, represented approximately 17% of sales
in the first quarter of fiscal year 1999 compared with 9% of sales in the first
quarter of fiscal year 1998. The loss or a substantial reduction in sales from
this customer would have a material adverse effect upon the Company's business.
Sales to Western Digital Corporation represented approximately 28% of sales in
the first quarter of the prior fiscal year but were less than 10% in the first
quarter of the current fiscal year.




                                      -11-



<PAGE>   12

FACTORS AFFECTING FUTURE RESULTS (continued)

The semiconductor market historically has been cyclical and subject to
significant economic fluctuations at various times. As a result, orders and
backlog may fluctuate widely from time to time. In prior public announcements,
the Company noted that weakness in the disk drive markets would negatively
impact its business. In addition, the Company disclosed that it also experienced
weakness in other served markets similar to that which has been reported by a
number of other semiconductor companies. This market condition resulted in a
reduction in scheduled orders in the first quarter of fiscal year 1999. The
Company believes that the level of some of its customers' inventories continues
to be high and that customers will work off these inventories before making
significant new purchasing commitments. Because of this and other factors, there
can be no assurance that the Company will not experience material fluctuations
in future operating results on a quarterly or annual basis as a result of its
inability to adjust its manufacturing capacity or its cost structure to
increased or reduced customer demand.

Presently, the Company is dependent upon GMT Microelectronics Corporation
("GMT"), an outside foundry, as its sole source of BiCMOS wafers which accounted
for approximately 40% of the Company's revenues in fiscal year 1998 and 41% in
the first three months of fiscal year 1999. The Company's dependence on GMT is
expected to continue until the Company's new 6" BiCMOS wafer fabrication
facility becomes operational, currently estimated to occur in July 1998, or
until the qualification of a second foundry source is completed. There can be no
assurance that GMT or third-party foundries will be able to meet the Company's
future BiCMOS wafer production requirements or that the new 6" BiCMOS wafer
fabrication facility will become operational as planned.

Construction of the Company's new 6" BiCMOS wafer fabrication facility has been
completed. Qualification of manufacturing processes and products is in process
and the new fab is expected to become operational in July 1998. There can be no
assurance that these processes and products will be qualified on time or that
the added capacity will match demand for its products. Delays in qualification
could significantly increase pre-operating costs. In addition, any constraints
in manufacturing and testing capacity could adversely affect the business of the
Company's customers and cause them to seek alternative sources for the products
currently obtained from the Company. Once operational, the Company's additional
capacity will also result in a significant increase in operating expenses, such
as depreciation, and if revenues do not increase to offset these additional
expenses, the Company's future operating results could be adversely affected.
Meanwhile, other semiconductor manufacturers are also expanding or planning to
expand their production capacity over the next several years. There can be no
assurance that the expansion by the Company and its competitors will not lead to
overcapacity in the industry, which could lead to price erosion that could
adversely affect the Company's operating results.

The Company has initiated a complete analysis of all computer-based software and
hardware to ensure Year 2000 compliance. In addition, the Company has begun
replacement of certain business systems with Year 2000 compliant software in
order to improve reporting and productivity. Formal communications have been
established with all significant vendors to determine the extent to which the
Company could be impacted by third parties' failure to remediate their own Year
2000 issues. The Company could be negatively impacted if it or a third party is
unsuccessful in properly addressing this issue. The Year 2000 project expense is
not anticipated to be material and is expected to be substantially completed by
the end of 1998.




                                      -12-



<PAGE>   13

FORWARD-LOOKING INFORMATION

The Private Securities Litigation Reform Act of 1995 ("the Act") provides a new
"safe harbor" for forward-looking statements so long as those statements are
identified as forward-looking and are accompanied by meaningful cautionary
statements identifying important factors that could cause actual results to
differ materially from those discussed in the statement. The Company desires to
take advantage of the new "safe harbor" provisions of the Act. Certain
information contained herein, particularly the information appearing under the
headings "Results of Operations," "Financial Condition," and "Factors Affecting
Future Results" is forward-looking.

Information regarding certain important factors that could cause actual results
of operations or outcomes of other events to differ materially from any such
forward-looking statement appears together with such statement, and/or elsewhere
herein. This information should be read in conjunction with the Company's annual
report on Form 10-K for the year ended January 31, 1998.









































                                      -13-



<PAGE>   14

                           PART II. OTHER INFORMATION
               Unitrode Corporation and Consolidated Subsidiaries
                                   May 2, 1998


ITEM 1.  LEGAL PROCEEDINGS

LINEAR TECHNOLOGY CORPORATION LAWSUIT:

In June, 1997, Linear Technology Corporation ("LTC") filed a complaint in the
U.S. District Court for the Northern District of California (San Jose Division)
alleging that certain products of the Company and products of four other
defendants infringe an LTC patent. The complaint seeks damages and an
injunction against infringement of the patent. The amount of damages is
unspecified in the complaint. The Company has denied any infringement and has
filed a counterclaim seeking that the patent be declared invalid. The case is
presently in the early stages of discovery. The Company believes that the
resolution of this action will not have a material adverse effect on the
Company's financial condition or results of operations.

ENVIRONMENTAL MATTERS:

The Company is involved in investigation and cleanup under the supervision
of the Maine Department of Environmental Protection of groundwater and soil
contamination at the former Westbrook, Maine wafer fabrication facility of its
former Semiconductor Products Division (the "Division"). Although the facility
was closed in 1989, the Division was sold in 1992 and the Westbrook, Maine real
estate was sold in 1994, the Company has retained responsibility for
environmental remediation at this site. The ultimate cost of cleanup at this
site is difficult to predict given the uncertainties regarding the extent of
the required cleanup. However, based upon the Company's experience at this
site, the Company has established a reserve, taking into account the probable
and reasonably estimable work to be done at this site, which the Company
believes to be adequate.

The Maine site is not a "potentially responsible party" ("PRP") site. The
Company has sole responsibility for remedition at the site. The Company has
installed a groundwater treatment system at the site that has been approved by
the Maine Department of Environmental Protection and is currently engaged in
remediation of the site. The annual cost of operation and maintenance of the
treatment system is approximately $50,000 and the annual cost of sampling and
analysis at the site is approximately $10,000. Additional sampling and
investigation costs during the current year to evaluate potential new
groundwater recovery locations to expedite site clean up are expected to be
approximately $46,000.

The Company has been notified by responsible state authorities in California
that it is one of a number of PRPs under relevant state statutes with respect to
a former hazardous waste treatment facility in Escondido, California (the
"Site"). The treatment facility was owned and operated by an entity wholly
unrelated to the Company. The Company, along with other financially viable PRPs,
has entered into a consent decree with governmental authorities regarding the
voluntary payment of cleanup costs and voluntary cleanup measures with respect
to the Site. The Company has established a reserve which the Company believes to
be adequate for future environmental remediation costs at this Site, based upon
the probable and reasonably estimable work to be done at the Site, the other
PRPs involved at the Site and the Company's volumetric level of contribution to
the Site which is less than one-half of one percent of the total volume of waste
contributed to the Site by the parties to the consent decree. In view of the
difficulty in quantifying the potential costs or damages arising from the
alleged environmental hazards, it is not possible to determine with certainty
the extent of the Company's potential exposure at the Site. However, based upon
its investigation to date, the Company believes that its exposure (without
giving effect to the joint and several liability provisions referred to below)
would not be material and the Company believes that the reserves established
with respect to these liabilities will be adequate. Further, although statutes
provide that all PRPs may be held jointly and severally liable for the costs of
investigation and remediation of a site, after consideration of the liabilities
of other PRPs with respect to the Site and their respective levels of financial
responsibility, the Company believes that its liability with respect to the Site
is not material. If any liability on the part of the Company were to be measured
by the ratio of the waste attributable to the Company over the total waste
involved, based on information presently available to the Company, the Company's
aggregate liability with respect to the Site would not be material.

Although the Company has been identified as a PRP at the California site,
management of the Company does not believe that a loss exceeding amounts
already recognized has been or will be incurred that is material to a decision
to buy or sell the Company's securities. In the California situation, the
Company is one among 53 PRPs who have executed a PRP Group Agreement. The
Company's volumetric share of waste contributed to the site has been determined
in the PRP allocation agreement to be 0.4 percent. The parties to this agreement
have agreed to share costs on a pro rata basis, determined by the amount of
waste contributed to the site. A number of financially responsible PRPs have
volumetric shares at levels considerably higher than the Company's share. The
PRPs have completed a remedial investigation and feasibility study under a
consent order entered into with the California Department of Toxic Substance
Control (the "DTSC"). A remedial action plan has been approved by the DTSC and
the PRPs are about to enter into an additional consent under which the remedial
action plan will be carried out. The budgeted costs of the PRP group to
complete remediation of the site are $15,000,000 of which the Company's share
would be approximately $60,000. The Company does not believe it to  be
reasonably possible that it will bear costs in the California situation in
excess of a pro rate share since the financial contribution of its portion is
not subject to uncertainty or dispute.

Environmental reserves are reviewed as events and developments warrant and
adjusted to reflect the likelihood of additional environmental expenditures.
Based upon information currently available to the Company, management believes
that any additional aggregate liability to which the Company may be subjected
from all the above-mentioned sites would not be material to future financial
results.

ITEM 2.  CHANGES IN THE RIGHTS OF THE COMPANY'S SECURITY HOLDERS

None.

ITEM 3.  DEFAULTS UPON SENIOR SECURITIES

Not Applicable.

ITEM 4.  SUBMISSION OF MATTERS TO A VOTE OF SECURITY HOLDERS

None.

































                                      -14-

<PAGE>   15

                           PART II. OTHER INFORMATION
               Unitrode Corporation and Consolidated Subsidiaries
                                   May 2, 1998


ITEM 5.  OTHER INFORMATION

None

ITEM 6.  EXHIBITS AND REPORTS ON FORM 8-K

         (a)      Exhibits

                  Exhibit 27 - Financial Data Schedule

         (b)      REPORTS ON FORM 8-K: On February 28, 1998, the Registrant
                  filed a report on Form 8-K announcing that it had entered into
                  a definitive agreement to merge with BENCHMARQ
                  Microelectronics, Inc.

                  On April 7, 1998, the Registrant filed a report on Form 8-K
                  announcing that it would record a pre-tax charge in the first
                  quarter of fiscal year 1999.


































                                      -15-



<PAGE>   16

               Unitrode Corporation and Consolidated Subsidiaries


                                   May 2, 1998




                                   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.



                                        UNITRODE CORPORATION



    June 16, 1998                       /s/ Robert J. Richardson
-----------------                       --------------------------------------
Date                                    Robert J. Richardson
                                        President and Chief Executive Officer



    June 16, 1998                       /s/ Cosmo S. Trapani
-----------------                       --------------------------------------
Date                                    Cosmo S. Trapani
                                        Executive Vice President and
                                        Chief Financial Officer
                                        (Principal Financial and Accounting
                                        Officer)





























                                      -16-