EXHIBIT 5.1

October 19, 2001


Applied Micro Circuits Corporation
6290 Sequence Drive
San Diego, CA  92121

Ladies and Gentlemen:

You have requested our opinion with respect to certain matters in connection
with the filing by Applied Micro Circuits Corporation (the "Company") of a
Registration Statement on Form S-8 (the "Registration Statement") with the
Securities and Exchange Commission covering the offering of up to 8,000,000
shares of the Company's Common Stock, $.01 par value (the "Shares"), pursuant to
its 1998 Employee Stock Purchase Plan, as amended (the "Plan").

In connection with this opinion, we have examined the Registration Statement and
related Prospectus, your Certificate of Incorporation and Bylaws, as amended,
and such other documents, records, certificates, memoranda and other instruments
as we deem necessary as a basis for this opinion. We have assumed the
genuineness and authenticity of all documents submitted to us as originals, the
conformity to originals of all documents submitted to us as copies thereof, and
the due execution and delivery of all documents where due execution and delivery
are a prerequisite to the effectiveness thereof.

On the basis of the foregoing, and in reliance thereon, we are of the opinion
that the Shares, when sold and issued in accordance with the Plan, the
Registration Statement and related Prospectus, will be validly issued, fully
paid, and nonassessable.

We consent to the filing of this opinion as an exhibit to the Registration
Statement.

Very truly yours,

COOLEY GODWARD LLP

By:  /s/ D. Bradley Peck
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     D. Bradley Peck