Exhibit 5.1

                          [PEPPER HAMILTON LETTERHEAD]

                                    October 9, 2003

Integrated Circuit Systems, Inc.
2435 Boulevard of the Generals
Norristown, PA 19403

          Re:  Registration Statement on Form S-3

Ladies and Gentlemen:

          We have acted as counsel to Integrated Circuit Systems, Inc., a
Pennsylvania corporation (the "Company"), in connection with the registration
under the Securities Act of 1933, as amended (the "Securities Act"), of a
primary offering (the "Offering") of the following securities of the Company,
which may be issued from time to time on a delayed or continuous basis pursuant
to Rule 415 under the Securities Act at an aggregate initial offering price not
to exceed $300,000,000: (a) shares of common stock, $0.01 par value per share
(the "Common Stock"); (b) shares of preferred stock, $0.01 par value per share
(the "Preferred Stock"); (c) debt securities (the "Debt Securities"); and (d)
warrants to acquire equity securities or debt securities of the Company (the
"Warrants" and, together with the Common Stock, Preferred Stock and Debt
Securities, the "Securities"). The Debt Securities may be issued pursuant to the
Indenture (the "Indenture") between the Company and a trustee to be named in
such Indenture, which has been filed as an exhibit to the Registration Statement
on Form S-3 filed by the Company under the Act with the Securities and Exchange
Commission (the "Commission") on or about the date hereof (the "Registration
Statement").

          This opinion is delivered in accordance with the requirements of Item
601(b)(5) of Regulation S-K under the Act.

          We have examined originals or copies, certified or otherwise
identified to our satisfaction, of (a) the Registration Statement; (b) the
Indenture, (c) the form of the Company's Amended and Restated Articles of
Incorporation (the "Articles of Incorporation") and Amended and Restated By-Laws
(the "By-Laws"), each as currently in effect; (d) certain resolutions of the
Board of Directors of the Company (the "Board") relating to, among other things,
the transactions giving rise to the issuance of the Securities; and (e) such
other documents as we have deemed necessary or appropriate as a basis for the
opinions set forth below.

          In rendering the opinions set forth below, we have assumed that (a)
all information contained in all documents reviewed by us is true and correct;
(b) all signatures on all documents examined by us are genuine; (c) all
documents submitted to us as originals are



Integrated Circuit Systems, Inc.
October 9, 2003
Page 2

authentic and all documents submitted to us as copies conform to the originals
of those documents; (d) each natural person signing any document reviewed by us
had the legal capacity to do so; (e) each person signing in a representative
capacity (other than on behalf of the Company) any document reviewed by us had
authority to sign in such capacity; (f) the Registration Statement, and any
amendments thereto (including post-effective amendments) will have become
effective and comply with all applicable laws; (g) a prospectus supplement will
have been prepared and filed with the Commission describing the Securities
offered thereby; (h) all Securities will be issued and sold in compliance with
applicable federal and state securities laws and in the manner stated in the
Registration Statement and the applicable prospectus supplement; (i) the
Indenture, together with any supplemental indenture or other instruments
establishing a series of Debt Securities to be issued under the Indenture, will
each be duly authorized, executed and delivered by the parties thereto in
substantially the form reviewed by us or with changes that do not affect the
opinions given hereunder; and (j) a definitive purchase, underwriting or similar
agreement with respect to any Securities offered will have been duly authorized
and validly executed and delivered by the Company and the other parties thereto.

          We have examined the Registration Statement, including the exhibits
thereto, and such other documents, corporate records, and instruments and have
examined such laws and regulations as we have deemed necessary for purposes of
rendering the opinions set forth herein. Based upon such examination and subject
to the further provisions hereof, we are of the following opinion:

          1.   With respect to the shares of Common Stock to be issued pursuant
to the Registration Statement, when (a) the Registration Statement has become
effective under the Securities Act, (b) the Company's Board of Directors (the
"Board") has taken all necessary corporate action to approve the issuance of
such shares of Common Stock, (c) the terms of the offer, issuance and sale of
the Common Stock have been duly established in conformity with the Articles of
Incorporation and By-laws, comply with all requirements or restrictions imposed
by any court or governmental body having jurisdiction over the Company and do
not violate any applicable law or result in a default under or breach of any
agreement or instrument binding on the Company, (d) certificates representing
such shares of Common Stock have been duly executed, countersigned, registered
and delivered in accordance with the applicable definitive purchase,
underwriting or similar agreement approved by the Board and (e) such shares of
Common Stock have been offered, issued and sold as contemplated in the
Registration Statement and any applicable prospectus supplement, upon payment of
the consideration provided for therein, the shares of Common Stock will be
validly issued, fully paid and nonassessable.

          2.   With respect to the shares of any series of Preferred Stock to be
issued pursuant to the Registration Statement, when (a) the Registration
Statement has become effective under the Securities Act, (b) the Board has taken
all necessary corporate action to approve the issuance and terms of the
Preferred Stock, (c) the appropriate statement or statements with respect to
shares relating to a class or series of the Preferred Stock to be offered,
issued and sold



Integrated Circuit Systems, Inc.
October 9, 2003
Page 3

under the Registration Statement have been duly authorized and adopted and filed
with the Secretary of the Commonwealth of Pennsylvania, (d) the terms of the
offer, issuance and sale of such shares of such class or series of Preferred
Stock have been duly established in conformity with the Articles of
Incorporation and By-laws, comply with all requirements or restrictions imposed
by any court or governmental body having jurisdiction over the Company and do
not violate any applicable law or result in a default under or breach of any
agreement or instrument binding upon the Company, (e) certificates representing
such shares of Preferred Stock have been duly executed, countersigned,
registered and delivered in accordance with the applicable definitive purchase,
underwriting or similar agreement approved by the Board and (f) such shares of
Preferred Stock have been offered, issued and sold as contemplated in the
Registration Statement and any applicable prospectus supplement, upon payment of
the consideration provided for therein, the shares of Preferred Stock will be
validly issued, fully paid and nonassessable.

          3.   With respect to the Debt Securities to be issued pursuant to the
Registration Statement, when (a) the Registration Statement has become effective
under the Securities Act, (b) the Board has taken all necessary corporate action
to approve the issuance of such Debt Securities and terms of the offering
thereof, (c) the terms of the Debt Securities and of their issue and sale have
been duly established in conformity with the Indenture and any applicable
supplemental indenture, comply with all requirements or restrictions imposed by
any court or governmental body having jurisdiction over the Company and do not
violate any applicable law or result in a default under or breach of any
agreement or instrument binding upon the Company and (d) such Debt Securities
have been duly executed and authenticated in accordance with the Indenture and
any applicable supplemental indenture and offered, issued and sold as
contemplated in the Registration Statement and any applicable prospectus
supplement, upon receipt of the requisite consideration for such Debt
Securities, such Debt Securities will constitute valid and legally binding
obligations of the Company.

          4.   With respect to the Warrants to be issued pursuant to the
Registration Statement, when (a) the Registration Statement has become effective
under the Securities Act, (b) the Board has taken all necessary corporate action
to approve the creation, issuance and terms of the Warrants, (c) the warrant
agreement or agreements relating to the Warrants have been duly authorized and
validly executed and delivered by the Company and the warrant agent appointed by
the Company, (d) the terms of the Warrants and of their issue and sale have been
duly established in conformity with the warrant agreement or agreements relating
to the Warrants, comply with all requirements or restrictions imposed by any
court or governmental body having jurisdiction over the Company and do not
violate any applicable law or result in a default under or breach of any
agreement or instrument binding upon the Company, (e) the Warrants or
certificates representing the Warrants have been duly executed, countersigned,
registered and delivered in accordance with the appropriate warrant agreement or
agreements and the applicable definitive purchase, underwriting or similar
agreement approved by the Board and (f) such



Integrated Circuit Systems, Inc.
October 9, 2003
Page 4

Warrants have been offered, issued and sold as contemplated in the Registration
Statement and any applicable prospectus supplement, upon payment of the
consideration provided for therein, the Warrants will be duly issued.

          The foregoing opinions are qualified to the extent that the
enforceability of any document, instrument or Securities may be limited by or
subject to bankruptcy, insolvency, fraudulent transfer or conveyance,
reorganization, moratorium or other similar laws relating to or affecting
creditors' rights generally, and general equitable or public policy principles.

          We express no opinions concerning (a) the validity or enforceability
of any provisions contained in Indenture or any other agreement setting forth
the terms, or otherwise relating to the issuance and sale, of the Securities
that purport to waive or not give effect to rights to notices, defenses,
subrogation or other rights or benefits that cannot be effectively waived under
applicable law; or (b) the enforceability of indemnification provisions to the
extent they purport to relate to liabilities resulting from or based upon
negligence or any violation of federal or state securities or blue sky laws.

          We express no opinion as to the laws of any other jurisdiction other
than the Federal laws of the United States of America and the Business
Corporation Law of the Commonwealth of Pennsylvania.

          We have relied as to certain matters on information obtained from
public officials, officers of the Company, and other sources believed by us to
be responsible and we have assumed that the Indenture and each other agreement
entered into in connection with the issuance and sale of the Securities will be
duly authorized, executed, and delivered by the respective parties thereto,
other than the Company, assumptions which we have not independently verified.

          Please note that we are opining only as to the matters expressly set
forth herein, and no opinion should be inferred as to any other matters. This
opinion is based upon currently existing statutes, rules, regulations and
judicial decisions, and we disclaim any obligation to update this opinion or
otherwise advise you of any change in any of these sources of law or subsequent
legal or factual developments which might affect any matters or opinions set
forth herein.

          We hereby consent to the filing of this opinion as an exhibit to the
Registration Statement and to the reference to this firm under the caption
"Legal Opinions" in the prospectus filed as part of the Registration 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 Act or the Rules and
Regulations promulgated thereunder.



Integrated Circuit Systems, Inc.
October 9, 2003
Page 5

          This opinion is furnished by us, as your counsel, in connection with
the filing of the Registration Statement and, except as provided in the
immediately preceding paragraph, is not to be used, circulated, quoted or
otherwise referred to for any other purpose without our express written
permission or relied upon by any other person.

                                           Very truly yours,

                                           /S/ PEPPER HAMILTON LLP

                                           PEPPER HAMILTON LLP