United States securities and exchange commission logo

                           September 25, 2020

       Christopher Brown
       General Counsel
       955 Perimeter Road
       Manchester, New Hampshire 03103

                                                        Re: ALLEGRO
                                                            Amendment No. 1 to
                                                            Draft Registration
Statement on Form S-1
                                                            Submitted September
11, 2020
                                                            CIK 0000866291

       Dear Mr. Brown:

             We have reviewed your amended draft registration statement and
have the following
       comments. In some of our comments, we may ask you to provide us with
information so we
       may better understand your disclosure.

              Please respond to this letter by providing the requested
information and either submitting
       an amended draft registration statement or publicly filing your
registration statement on
       EDGAR. If you do not believe our comments apply to your facts and
circumstances or do not
       believe an amendment is appropriate, please tell us why in your

             After reviewing the information you provide in response to these
comments and your
       amended draft registration statement or filed registration statement, we
may have additional

       Amendment No. 1 to Draft Registration Statement on Form S-1 filed
September 11, 2020

       Non-GAAP Financial Metrics
       Adjusted Gross Profit and Adjusted Gross Margin
       Adjusted EBITDA and Adjusted EBITDA Margin, page 96

   1.                                                   We have reviewed your
responses to comments 5 and 6 as well as your revised disclosure.
                                                        It appears that the
calculation of your non-GAAP measures include adjustments for
                                                        normal, recurring
operating expenses that were necessary to operate your business at the
                                                        time those costs were
incurred. Accordingly, please modify the calculation of Adjusted
                                                        EBITDA and, as
applicable, Adjusted Gross Profit as follows for each adjustment noted
 Christopher Brown
September 25, 2020
Page 2

            AMTC Facility consolidation savings. Exclude all adjustments for
          expenses incurred.
            Labor savings. Exclude all adjustments operating expenses,
including but not limited
          to wages for employees whose positions were eliminated and the offset
of wages for
          newly hired employees.

      Please refer to Question 100.01 of the Non-GAAP Measures, Compliance and
2.    Please explain to us in more detail the nature of the following
adjustments you have made
      to calculate Adjusted Gross Profit and Adjusted EBITDA and why this
results in measures
      that are useful to investors. Clarify if any of the amounts reported for
these adjustments
      was an estimate rather than an actual amount of a cost incurred,
including the following:

            Loss (gain) from equity method investment
            Inventory cost amortization
            Foundry service payment
            Polar & Sanken distribution agreement
3.    We note that you include an adjustment for Severance in your calculation
of Adjusted
      EBITDA and that your adjustments for Labor savings and AMTC Facility
      savings appear to also include amounts related to severance. Please
clearly describe to us
      the nature and source of the severance amounts included in each line
       You may contact Kevin Stertzel at 202-551-3723 or Martin James at
202-551-3671 if you
have questions regarding comments on the financial statements and related
matters. Please
contact Erin Purnell at 202-551-3454 or Geoffrey Kruczek at 202-551-3641 with
any other

FirstName LastNameChristopher Brown
                                                           Division of
Corporation Finance
                                                           Office of
September 25, 2020 Page 2
cc:       Keith L. Halverstam
FirstName LastName