Mail Stop 6010
      February 22, 2006

David R. Sonksen, CFO
Microsemi Corporation
2381 Morse Avenue
Irvine, California 92614

      Re:	Microsemi Corporation
      Amendment No. 1 to Registration Statement on Form S-4
      Filed February 10, 2006
		File No. 333-130655

Dear Mr. Sonksen:

      We have reviewed your filing and have the following
comments.
Where indicated, we think you should revise your document in
response
to these comments.  If you disagree, we will consider your
explanation as to why our comment is inapplicable or a revision is
unnecessary.  Please be as detailed as necessary in your
explanation.
In some of our comments, we may ask you to provide us with
information so we may better understand your disclosure.  After
reviewing this information, we may raise additional comments.

      Please understand that the purpose of our review process is
to
assist you in your compliance with the applicable disclosure
requirements and to enhance the overall disclosure in your filing.
We look forward to working with you in these respects.  We welcome
any questions you may have about our comments or any other aspect
of
our review.  Feel free to call us at the telephone numbers listed
at
the end of this letter.

      Prior comment refers to our letter dated January 19, 2006.

Prospectus Cover Page

1. Please disclose that shareholders will not know at the time of
the
vote the number of shares and amount of cash that they will
receive
in the merger.  Also, revise your disclosure throughout your
document
to make clear that the amounts may be adjusted.

2. Please tell us why you believe it is appropriate to seek
shareholder approval for a transaction where the mix of cash and
stock for a transaction may change after the vote.

Microsemi may be held liable for damages, page 19

3. Please refer to prior comment 1.  Please file as an exhibit the
November 1998 agreement.

Representations and Warranties in the Merger Agreement, page 20

4. We note your statement that the representations and warranties
"are not to be relied upon by you whatsoever as factual
statements."
Please revise to remove any potential implication that the
referenced
disclosure does not constitute public disclosure under the federal
securities laws.
Please be advised that, notwithstanding the inclusion of a general
disclaimer, you are responsible for considering whether additional
specific disclosures of material information regarding material
contractual provisions are required to make the statements
included
in the proxy statement/prospectus not misleading.  Include
disclosure
acknowledging that, if specific material facts exist that
contradict
the representations or warranties in the merger agreement, you
have
provided corrective disclosure.

Microsemi`s Reasons for the Merger, page 41 & APT`s Reasons for
the
Merger, page 51

5. Please revise these sections to clarify, if applicable, whether
the boards considered the change in the number of shares.

Material  U.S. Federal Income Tax Consequences of the Merger, page
73

6. We reissue prior comment 17.  You should unequivocally state
what
the tax consequences will be.  We note the disclosure on page 4
concerning the expectation, the disclosure on page 52 about the
tax
consequences if the merger fails to qualify as a reorganization
and
the disclosure on page 73 about the intent.

7. We reissue prior comment 18 with respect to Microsemi.  Also,
before this registration statement is effective, you must file a
signed opinion of counsel from APT`s counsel.
General

8. We noted that you filed your Form 10-Q for the period ended
January 1, 2006 on February 10, 2006.  However, it does not appear
that you have incorporated this report by reference into your Form
S-
4.  Without including or incorporating by reference this Form 10-Q
into your Form S-4, it does not appear that you meet the updating
requirements of Article 3 of Regulation S-X. Please revise or
advise.

9. Consideration should be given to the updating requirements of
Rule
3-12 of Regulation S-X with regards to Advanced Power Technology.
Please note that if the anticipated effective date falls after 45
days following the end of the fiscal year, audited financial
statements will be required at that time unless the company, in
good
faith, expects to report income after taxes. Based on the Selected
Historical Financial Information, as provided on page 22 of Form
S-4,
it appears that Advanced Power Technology will report a net loss
for
the year ended December 31, 2005. Please advise.

********

      As appropriate, please amend your registration statement in
response to these comments.  You may wish to provide us with
marked
copies of the amendment to expedite our review.  Please furnish a
cover letter with your amendment that keys your responses to our
comments and provides any requested information.  Detailed cover
letters greatly facilitate our review.  Please understand that we
may
have additional comments after reviewing your amendment and
responses
to our comments.

      You may contact Julie Sherman at (202) 551-3640 or Kaitlin
Tillan at (202) 551-3604 if you have questions regarding comments
on
the financial statements and related matters.  Please contact Alan
Morris at (202) 551-3601 or me at (202) 551-3602 with any other
questions.

      					Sincerely,


      					Thomas Jones
      					Senior Attorney

cc. Nicholas J. Yocca
      via Telefax (949) 203-6161
David R. Sonksen, CFO
Microsemi Corporation
February 22, 2006
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