As filed with the Securities and Exchange Commission on August 29, 1997
                                                       Registration No. 33-90392

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                       SECURITIES AND EXCHANGE COMMISSION
                             Washington, D.C. 20549

                         POST EFFECTIVE AMENDMENT NO. 1
                                   TO FORM S-3
             REGISTRATION STATEMENT UNDER THE SECURITIES ACT OF 1933

                                PMC-SIERRA, INC.
               (Exact name of issuer as specified in its charter)



         DELAWARE                                        94-2925073
 ------------------------                   ------------------------------------
 (State of Incorporation)                   (I.R.S. Employer Identification No.)

                             105 - 8555 Baxter Place
                    Burnaby, British Columbia, Canada V5A 4V7
                    (Address of principal executive offices)

                          The Corporation Trust Company
                               1209 Orange Street
                           Wilmington, Delaware 19801
                                 (800) 677-3394
            (Name, address and telephone number of agent for service)

                                    Copy to:
                                  Neil J. Wolff
                       Wilson, Sonsini, Goodrich & Rosati
                            Professional Corporation
                               650 Page Mill Road
                        Palo Alto, California 94304-1050

   Approximate date of commencement of proposed sale to the public under this
Registration Statement: As soon as practicable after this Registration Statement
                               becomes effective.

If the only securities  being registered on this Form are being offered pursuant
to dividend or interest reinvestment plans, please check the following box. / /

If any of the  securities  being  registered on this Form are to be offered on a
delayed or continuous  basis  pursuant to Rule 415 under the  Securities  Act of
1933, other than securities offered only in connection with dividend or interest
reinvestment plans, check the following box. /X/

The Registrant hereby amends this  Registration  Statement on such date or dates
as may be necessary to delay its effective date until the Registrant  shall file
a further  amendment that specifically  states that this Registration  Statement
shall  thereafter  become  effective  in  accordance  with  Section  8(a) of the
Securities Act of 1933, as amended,  or until this Registration  Statement shall
become effective on such date as the Commission, acting pursuant to said Section
8(a), may determine.

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Information   contained  herein  is  subject  to  completion  or  amendment.   A
registration  statement  relating  to these  securities  has been filed with the
Securities  and Exchange  Commission.  These  securities may not be sold nor may
offers to buy be accepted prior to the time the registration  statement  becomes
effective.  This  prospectus  shall  not  constitute  an  offer  to  sell or the
solicitation of an offer to buy nor shall there be any sale of these  securities
in any State in which such offer,  solicitation  or sale would be unlawful prior
to  registration or  qualification  under the securities laws of any such State.
- --------------------------------------------------------------------------------

Subject to Completion
PROSPECTUS SUPPLEMENT
- ---------------------

                                PMC-SIERRA, INC.

                                EXPLANATORY NOTE

         This   Post-effective   Amendment  No.  1  (the   "Amendment")  to  the
Registration Statement on Form S-3 (No. 33-90392) (the "Registration Statement")
is being filed pursuant to Rule 414 under the Securities Act of 1933, as amended
(the "Securities Act") by PMC-Sierra,  Inc., a Delaware corporation incorporated
in May 1997 (the  "Company").  The Company is the successor to PMC-Sierra,  Inc.
(formerly  named Sierra  Semiconductor  Corporation),  a California  corporation
("Sierra"),  following a  statutory  merger  (the  "Merger")  for the purpose of
changing Sierra's state of incorporation from California to Delaware,  effective
as of July  10,  1997.  Prior  to the  Merger,  the  Company  had no  assets  or
liabilities  other than nominal assets or  liabilities.  In connection  with the
Merger,  the  Company  succeeded  by  operation  of law to all of the assets and
liabilities of Sierra.  The Merger was approved by the shareholders of Sierra at
a meeting for which  proxies  were  solicited  pursuant to Section  14(a) of the
Securities Exchange Act of 1934, as amended (the "Exchange Act").

         Except as modified by this  Amendment,  the Company,  by virtue of this
Amendment,  expressly adopts the Registration  Statement as its own registration
statement  for  all  purposes  of the  Securities  Act  and  the  Exchange  Act.
Additional  information  necessary  to  reflect  any  material  change  made  in
connection with or resulting from the Merger is set forth below.


                 INCORPORATION OF CERTAIN DOCUMENTS BY REFERENCE

         In addition to the documents which have been  incorporated by reference
by the Company's  predecessor and made a part of the  Prospectus,  the following
documents, which have been filed by the Company with the Securities and Exchange
Commission (the "Commission"),  are incorporated by reference and made a part of
this  Prospectus:  (i) the  Quarterly  Report on Form 10-Q for the quarter ended
June 30, 1997, and the Current Report on Form 8-K filed on August 8, 1997, filed
pursuant to the Exchange Act;  (ii) the  description  of the  Company's  Capital
Stock set forth in  Amendment  No. 2 to the  Registration  Statement on Form S-3
(File No.  333-15519);  and (iii) all reports,  definitive  proxy  statement and
other  documents  filed by the Company with the  Commission  pursuant to Section
13(a),  13(c),  14 or 15(d) of the Exchange Act  subsequent  to the date of this
Prospectus and prior to the termination of the Offering.




                                     PART II

                     INFORMATION NOT REQUIRED IN PROSPECTUS

Item 15  Indemnification of Directors and Officers.
         ------------------------------------------

         The  Certificate  of  Incorporation  of  the  Company   eliminates  the
liability  of  directors  to the  Company  for  monetary  damages  for breach of
fiduciary  duty as a director to the fullest extent  permissible  under Delaware
law, as such law exists  currently or as it may be amended in the future.  Under
Delaware  law,  such  provision  may not  eliminate or limit  director  monetary
liability for: (a) breaches of the director's  duty of loyalty to the Company or
its  stockholders;  (b)  acts  or  omissions  not in  good  faith  or  involving
intentional misconduct or knowing violations of law; (c) the payment of unlawful
dividends or unlawful stock  repurchases or redemptions;  or (d) transactions in
which the director  received an improper  personal  benefit.  Such limitation of
liability provisions also may not limit a director's liability for violation of,
or  otherwise  relieve  the  Company  or its  directors  from the  necessity  of
complying with,  federal or state securities laws, or affect the availability of
non-monetary remedies such as injunctive relief or rescission.

         The  Company's  Bylaws  provide that the Company  shall  indemnify  its
directors  and officers and may  indemnify its employees and other agents to the
fullest extent permitted by law. The Company believes that indemnification under
its  Bylaws  covers  at least  negligence  and gross  negligence  on the part of
indemnified  parties.  The  Company's  Bylaws  also permit the Company to secure
insurance  on behalf of any officer,  director,  employee or other agent for any
liability  arising out of his or her  actions in such  capacity,  regardless  of
whether the Company  would have the power to  indemnify  him or her against such
liability under the General  Corporation Law of Delaware.  The Company currently
has secured such insurance on behalf of its officers and directors.

         The Company has entered into  agreements to indemnify its directors and
officers,  in addition to indemnification  provided for in the Company's Bylaws.
Subject to certain conditions,  these agreements,  among other things, indemnify
the Company's directors and officers for certain expenses (including  attorney's
fees),  judgments,  fines and settlement  amounts incurred by any such person in
any  action  or  proceeding,  including  any  action  by or in the  right of the
Company,  arising out of such person's  services as a director or officer of the
Company,  any  subsidiary  of the Company or any other  company or enterprise to
which the person provides services at the request of the Company.






Item 16   Exhibits.
          --------

The following exhibits are filed as part of this Registration Statement:


             NUMBER    EXHIBIT DESCRIPTION
             ------    -------------------

             4.1(1)    Certificate of Incorporation of the Company.

             4.2(2)    Bylaws of the Company.

             4.3       Fourth Article of Certificate of Incorporation  (included
                       in Exhibit 4.1 above).

             4.4       Specimen of the Company's Common Stock Certificate.

             5.1       Opinion of Counsel as to validity of the Shares.

             23.1      Consent of Counsel (included in Exhibit 5.1 above).

             23.2      Consent of Ernst & Young LLP.

             24.1      Power of Attorney (included on the Signature page to this
                       Amendment).

- ----------------------

(1)      Incorporated  by  reference  to  Exhibit 3.1 filed  with  the Company's
         Quarterly Report on Form 10-Q for the quarter ended June 30, 1997.

(2)      Incorporated  by  reference  to  Exhibit 3.3 filed with  the  Company's
         Quarterly Report on Form 10-Q for the quarter ended June 30, 1997.






                                   SIGNATURES
                                   ----------

         Pursuant  to the  requirements  of the  Securities  Act  of  1933,  the
Registrant  has  duly  caused  this  Post-effective   Amendment  No.  1  to  its
Registration  Statement on Form S-3 (No. 33-90392) to be signed on its behalf by
the  undersigned,  thereunto duly  authorized,  in the City of Burnaby,  British
Columbia, Canada, on this 26th day of August, 1997.

                                PMC-SIERRA, INC.

                                       By:  /s/ ROBERT L. BAILEY
                                            Robert L. Bailey
                                            Chief Executive Officer
                                            (Principal Executive Officer)
                                            (Duly Authorized Officer)


                                POWER OF ATTORNEY
                                -----------------

         KNOW ALL PERSONS BY THESE  PRESENTS,  that each person whose  signature
appears  below  constitutes  and  appoints  Robert L. Bailey and John  Sullivan,
jointly  and  severally,   his   attorneys-in-fact,   each  with  the  power  of
substitution,  for him in any and all capacities, to sign any amendments to this
Registration  Statement on Form S-3 (No.  33-90392),  and to file the same, with
exhibits  thereto  and  other  documents  in  connection  therewith,   with  the
Securities  and Exchange  Commission,  hereby  ratifying and confirming all that
each of said  attorneys-in-fact,  or his  substitute or  substitutes,  may do or
cause to be done by virtue hereof.

         Pursuant to the requirements of the Securities Act, this Post-Effective
Amendment  No. 1 to the  Registration  Statement on Form S-3 (No.  33-90392) has
been  signed  by the  following  persons  in  the  capacities  and on the  dates
indicated.


         Signature             Title                                  Date
         ---------             -----                                  ----


/S/ ROBERT L. BAILEY          Director and Chief Executive       August 26, 1997
- -----------------------       Officer (Principal Executive
Robert L. Bailey              Officer)


/S/ JOHN SULLIVAN             Vice President, Finance and        August 26, 1997
- -----------------------       Chief Financial Officer     
John Sullivan                 (Principal Financial and
                              Accounting Officer)


/S/ JAMES V. DILLER           Chairman of the Board of           August 26, 1997
- -----------------------       Directors
James V. Diller


/S/ ALEXANDRE BALKANSKI       Director                           August 26, 1997
- -----------------------
Alexandre Balkanski


                              Director                           August __, 1997
- -----------------------
Colin Beaumont


/S/ MICHAEL L. DIONNE         Director                           August 26, 1997
- -----------------------
Michael L. Dionne


/S/ FRANK J. MARSHALL         Director                           August 27, 1997
- -----------------------
Frank J. Marshall






                                  EXHIBIT INDEX


             NUMBER       EXHIBIT DESCRIPTION
             ------       -------------------

             4.4          Specimen of the Company's Common Stock Certificate.

             5.1          Opinion of Counsel as to validity of the Shares.

             23.1         Consent of Counsel (included in Exhibit 5.1, above).

             23.2         Consent of Ernst & Young LLP.