<PAGE>


                                                                   Exhibit 10.80


                              REVOLVING CREDIT NOTE


$15,000,000.00                                  Boston, Massachusetts
                                                March 1, 1999


         FOR VALUE RECEIVED, the undersigned (the "Borrower") absolutely and
unconditionally promises to pay to BANKBOSTON, N.A. (the "Lender"), or order,
the principal amount of Fifteen Million Dollars ($15,000,000.00) or, if less,
the aggregate unpaid principal amount of all Revolving Loans (as defined in the
Agreement referred to below) made by the Lender to the Borrower pursuant to the
Agreement and noted on the records of the Lender, such payment to be made as
hereinafter provided, together with interest (computed on the basis of the
actual number of days elapsed over a 360-day year) on the unpaid principal
amount hereof until paid in full.

         The entire unpaid principal (not at the time overdue) of this Note
shall bear interest at the rate or rates from time to time in effect under the
Agreement, as defined below. Accrued interest on the unpaid principal under this
Note shall be payable on the dates specified in the Agreement.

         The Borrower absolutely and unconditionally agrees to repay so much of
the Revolving Loans as may be necessary so that the aggregate outstanding
principal amount of the Revolving Loans will not exceed the Maximum Amount. On
June 30, 2001, the date of the final maturity of this Note, there shall become
absolutely due and payable by the Borrower hereunder, and the Borrower hereby
promises to pay to the holder hereof, the balance (if any) of the principal
hereof then remaining unpaid, all of the unpaid interest accrued hereon and all
(if any) other amounts payable on or in respect of this Note or the indebtedness
evidenced hereby.

         All payments under this Note shall be made at the head office of the
Lender at 100 Federal Street, Boston, Massachusetts 02110 (or at such other
place as the Lender may designate from time to time in writing) in lawful money
of the United States of America in federal or other immediately available funds.
Subject to the provisions of Section 2.4 of the Agreement, the Borrower may
prepay this Note in whole or in part at any time without premium or penalty.
Amounts so paid and other amounts may be borrowed and reborrowed by the Borrower
hereunder from time to time as provided in the Agreement referred to below.

         This Note is issued pursuant to, is entitled to the benefits of, and is
subject to the provisions of a certain Loan Agreement of even date herewith by
and between the undersigned and the Lender (herein, as the same may from time to
time be amended or extended, referred to as the "Agreement"), but neither this
reference to the Agreement nor any provision thereof shall affect or impair the
absolute and unconditional obligation of the undersigned maker of this Note to
pay the principal of and interest on this Note as herein provided.

         Upon an Event of Default, as defined in the Agreement, the aggregate
unpaid balance of principal plus accrued interest may become or may be declared
to be due and payable in the manner and with the effect provided in the
Agreement.

         The maker of this Note hereby waives presentment, demand, notice of
dishonor, protest and all other demands and notices in connection with the
delivery, acceptance, performance and enforcement of this Note.


<PAGE>


         WITNESS the execution of this Note under seal on the date written
above.


                                          C.P. CLARE CORPORATION

WITNESS:


                                          By:
-----------------------                       ----------------------------------
                                          Name: Harry Andersen
                                          Title: Senior Vice President and
                                                  Chief Financial Officer