EXHIBIT 8.2

             [letterhead of Wilson Sonsini Goodrich & Rosati, P.C.]

                                        September   , 2000

MMC Networks
1144 E. Arques Avenue
Sunnyvale, California 94805

Ladies and Gentlemen:

   We have acted as counsel to MMC Networks, Inc., a Delaware corporation (the
"Company"), in connection with the preparation and execution of the Agreement
and Plan of Merger and Reorganization dated as of August 28, 2000 (the "Merger
Agreement") by and among Applied Micro Circuits Corporation, a Delaware
corporation ("Parent"), Mercury Acquisition Corp., a Delaware corporation and
wholly-owned subsidiary of Parent ("Merger Sub"), and the Company. The Merger
and certain proposed transactions incident thereto are described in the
Registration Statement on Form S-4 (the "Registration Statement") of Parent,
which includes the Prospectus/Proxy Statement of Parent ("Proxy Statement"),
which is being filed with the U.S. Securities and Exchange Commission under the
Securities Act of 1933 and which became effective on      , 2000.

   You have requested our opinion regarding certain federal income tax
consequences of the Merger. In connection with rendering this opinion, we have
assumed and relied upon (without any independent investigation):

   1. The truth and accuracy of the statements, covenants, representations and
warranties contained in the Merger Agreement, in the representations received
by us from Company, Parent and Merger Sub dated as of      , 2000 (the "Tax
Representation Letters") and in the Registration Statement;

   2. Consummation of the Merger in accordance with the Merger Agreement,
without any waiver, breach or amendment of any material provisions of the
Merger Agreement, the effectiveness of the Merger under applicable state law,
and the performance of all covenants contained in the Merger Agreement and the
Tax Representation Letters without waiver or breach of any material provisions
thereof;

   3. The accuracy of any representation or statement made "to the knowledge
of" or similarly qualified without such qualification, and as to all matters in
which a person or entity is making a representation, that such person or entity
is not a party to, does not have, or is not aware of, any plan, intention,
understanding or agreement inconsistent with such representation, and there is
no such plan, intention, understanding, or agreement inconsistent with such
representation;

   4. The reporting of the Merger as a reorganization, within the meaning of
Section 368(a) of the Internal Revenue Code of 1986, as amended (the "Code"),
by Parent in its federal income tax return;

   5. The authenticity of original documents (including signatures), conformity
to the originals of documents submitted to us as copies, and due execution and
delivery of all documents where due execution and delivery are prerequisites to
effectiveness thereof; and

   6. The absence of any occurrence since the date of the Tax Representation
Letters, which change could have caused any of the declarations and
representations contained in those letters to be untrue, incorrect or
incomplete in any respect at any time since that date.


MMC Networks, Inc.
September   , 2000
Page 2

   Based upon the foregoing, the discussion contained in the Proxy Statement
under the caption "Material Federal Income Tax Consequences," subject to the
limitations and qualifications described therein and herein, and as of       ,
2000, sets forth the material federal income tax considerations generally
applicable to the Merger.

   This opinion represents our best judgment regarding the application of
federal income tax laws under the Code, existing judicial decisions,
administrative regulations and published rulings and procedures. Our opinion is
not binding upon the Internal Revenue Service or the courts, and there is no
assurance that the Internal Revenue Service will not successfully assert a
contrary position. Furthermore, no assurance can be given that future
legislative, judicial or administrative changes, on either a prospective or a
retroactive basis, would not adversely affect the accuracy of the conclusions
stated herein. We undertake no responsibility to advise you of any new
developments in the application or interpretation of the federal income tax
laws. If any one of the statements, covenants, representations, warranties or
assumptions upon which we have relied to issue this opinion is incorrect, our
opinion might be adversely affected and may not be relied upon.

   This opinion addresses only the matters described above, and does not
address any other federal, state, local or foreign tax consequences that may
result from the Merger or any other transaction undertaken in connection with
the Merger.

   This opinion is rendered only to you and is solely for your benefit in
connection with filing the Registration Statement with the Securities and
Exchange Commission. This opinion may not be relied upon for any other purpose
or by any other person or entity, and may not be furnished to, quoted to or by
or relied upon by any other person or entity, without our prior written
consent. We hereby consent to the use of this opinion as an exhibit to the
Registration Statement and to the use of our name under the caption "Material
Federal Income Tax Consequences" in the Proxy Statement. In giving such
consent, we do not thereby admit that we are in the category of persons whose
consent is required under Section 7 of the Securities Act of 1933, as amended,
nor do we thereby admit that we are experts with respect to any part of such
Registration Statement within the meaning of the term "experts" as used in the
Securities Act of 1933, as amended.

                                          Very truly yours,