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                                                                   EXHIBIT 4.2.5

                               AMENDMENT NO. 5 TO

                        PREFERRED SHARES RIGHTS AGREEMENT

      This AMENDMENT NO. 5 TO PREFERRED SHARES RIGHTS AGREEMENT dated as of
April 22, 2004 (the "Amendment") is made by and between Catalyst Semiconductor,
Inc., a Delaware corporation (the "Company") and EquiServe Trust Company, N.A.,
as rights agent (the "Rights Agent").

                                    RECITALS

      WHEREAS, the Company and the Rights Agent are parties to a Preferred
Shares Rights Agreement dated as of December 3, 1996, as amended (the "Rights
Agreement");

      WHEREAS, in connection with the sale by Elex N.V. to the Company of
600,000 shares of the Company's Common Stock, and pursuant to Section 27 of the
Rights Agreement, the Board of Directors of the Company has determined that an
amendment to the Rights Agreement as set forth herein is necessary and
desirable, and the Company and the Rights Agent desire to evidence such
amendment in writing.

      NOW, THEREFORE, for good and valuable consideration, the receipt and
sufficiency of which are hereby acknowledged, the Company and the Rights Agent
hereby agree as follows:

      1.    Amendment of Section 1(a). Section 1(a) of the Rights Agreement,
which currently reads as follows:

            "Notwithstanding anything in this Rights Agreement to the contrary,
      neither Elex NV ("Elex") (or its Affiliates or Associates) nor Roland
      Duchatelet (or his Affiliates or Associates) shall be deemed to be an
      Acquiring Person solely by virtue of the announcement, occurrence or
      continuance of (i) the execution of the Common Stock Purchase Agreement
      dated as of May 26, 1998 between Elex and the Company (the "Purchase
      Agreement"), (ii) the execution of the Common Stock Purchase Agreement
      dated as of September 14, 1998 between Elex and the Company (the "Second
      Purchase Agreement"), (iii) the issuance to Elex of 1,500,000 shares of
      Common Stock of the Company in accordance with the terms of the Purchase
      Agreement and 4,000,000 shares of Common Stock of the Company in
      accordance with the terms of the Second Purchase Agreement, (iv) the grant
      of options to purchase shares of the Company's Common Stock to Mr. Roland
      Duchatelet in connection with his position as a member of the Board of
      Directors of the Company, (v) the issuance of shares of Common Stock upon
      the exercise by Mr. Roland Duchatelet of any options granted to Mr.
      Duchatelet in connection with his position as a member of the Board of
      Directors of the Company, (vi) any purchase by Elex (or its Affiliates or
      Associates) or Mr. Duchatelet (or his Affiliates or Associates) of shares
      of the Company's Common Stock in the open market from time to time, so
      long as any such purchase of shares does not cause Elex (and its
      Affiliates and Associates) and Mr. Duchatelet (and his Affiliates and
      Associates) collectively at the time of such purchase to be or to become
      deemed to be the Beneficial Owner of more than 5,500,000 shares of the
      Company's Common Stock in the aggregate (as appropriately

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      adjusted for stock splits, stock dividends and the like) (together with
      the shares described in clauses (iii), (iv) and (v) above, the "PERMITTED
      SHARES"), or (vii) Elex (or its Affiliates or Associates) or Mr.
      Duchatelet (or his Affiliates or Associates) holding or being deemed a
      Beneficial Owner of the Permitted Shares; provided, however, that if Elex
      (or its Affiliates or Associates) or Mr. Duchatelet (or his Affiliates or
      Associates), at any time after the issuance or purchase of any and all
      Permitted Shares, shall be or become deemed to be the Beneficial Owner of
      shares of Common Stock of the Company other than the Permitted Shares,
      then such exemptions from being deemed an Acquiring Person contained in
      this sentence shall not be applicable.

is hereby amended in its entirety to read as follows:

            "Notwithstanding anything in this Rights Agreement to the contrary,
      neither Elex NV ("Elex") (or its Affiliates or Associates) nor Roland
      Duchatelet (or his Affiliates or Associates) shall be deemed to be an
      Acquiring Person solely by virtue of the announcement, occurrence or
      continuance of (i) the execution of the Common Stock Purchase Agreement
      dated as of May 26, 1998 between Elex and the Company (the "Purchase
      Agreement"), (ii) the execution of the Common Stock Purchase Agreement
      dated as of September 14, 1998 between Elex and the Company (the "Second
      Purchase Agreement"), (iii) the issuance to Elex of 1,500,000 shares of
      Common Stock of the Company in accordance with the terms of the Purchase
      Agreement and 4,000,000 shares of Common Stock of the Company in
      accordance with the terms of the Second Purchase Agreement, (iv) the grant
      of options to purchase shares of the Company's Common Stock to Roland
      Duchatelet in connection with his position as a member of the Board of
      Directors of the Company, (v) the issuance of shares of Common Stock upon
      the exercise by Roland Duchatelet of any options granted to Mr. Duchatelet
      in connection with his position as a member of the Board of Directors of
      the Company, (vi) any purchase by Elex (or its Affiliates or Associates)
      or Mr. Duchatelet (or his Affiliates or Associates) of shares of the
      Company's Common Stock in the open market from time to time, so long as
      any such purchase of shares does not cause Elex (and its Affiliates and
      Associates) and Mr. Duchatelet (and his Affiliates and Associates)
      collectively at the time of such purchase to be or to become deemed to be
      the Beneficial Owner of more than (1) 3,687,007 shares of the Company's
      Common Stock in the aggregate (as appropriately adjusted for stock splits,
      stock dividends and the like) less (2) the number of shares of Common
      Stock (as appropriately adjusted for stock splits, stock dividends and the
      like) sold, transferred or otherwise disposed of by Elex (and its
      Affiliates and Associates) after April 22, 2004 (together with the shares
      described in clauses (iii), (iv) and (v) above, the "Permitted Shares"),
      or (vii) Elex (or its Affiliates or Associates) or Mr. Duchatelet (or his
      Affiliates or Associates) holding or being deemed a Beneficial Owner of
      the Permitted Shares; provided, however, that if Elex (or its Affiliates
      or Associates) or Mr. Duchatelet (or his Affiliates or Associates), at any
      time after the issuance or purchase of any and all Permitted Shares, shall
      be or become deemed to be the Beneficial Owner of shares of Common Stock
      of the Company other than the Permitted Shares, then such exemptions from
      being deemed an Acquiring Person contained in this sentence shall not be
      applicable; provided further, however, that the exemptions contained in
      this sentence shall not be applicable from and after the date that Elex
      (and its Affiliates or Associates) and Mr. Duchatelet (and his

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      Affiliates or Associates) Beneficially Own less than 15% of the Common
      Shares then outstanding.

      2.    Amendment of Section 20. Section 20 of the Rights Agreement is
amended to insert a new Section 20(l) to read as follows:

            "(l)  Notwithstanding anything to the contrary contained herein, the
      Rights Agent shall not be liable for any delays or failures in performance
      resulting from acts beyond its reasonable control including, without
      limitation, acts of God, terrorist acts, shortage of supply, breakdowns or
      malfunctions, interruptions or malfunction of computer facilities, or loss
      of data due to power failures or mechanical difficulties with information
      storage or retrieval systems, labor difficulties, war, or civil unrest."

      3.    Amendment of Section 21. Section 21 of the Rights Agreement, which
currently reads as follows:

            "The  Rights Agent or any successor Rights Agent may resign and be
discharged from its duties under this Agreement upon thirty (30) days' notice in
writing mailed to the Company and to each transfer agent of the Preferred Shares
and the Common Shares by registered or certified mail. The Company may remove
the Rights Agent or any successor Rights Agent upon thirty (30) days' notice in
writing, mailed to the Rights Agent or successor Rights Agent, as the case may
be, and to each transfer agent of the Preferred Shares and the Common Shares by
registered or certified mail. If the Rights Agent shall resign or be removed or
shall otherwise become incapable of acting, the Company shall appoint a
successor to the Rights Agent. If the Company shall fail to make such
appointment within a period of thirty (30) days after giving notice of such
removal or after it has been notified in writing of such resignation or
incapacity by the resigning or incapacitated Rights Agent or by the holder of a
Rights Certificate (who shall, with such notice, submit his or her Rights
Certificate for inspection by the Company), then the Rights Agent or the
registered holder of any Rights Certificate may apply to any court of competent
jurisdiction for the appointment of a new Rights Agent. Any successor Rights
Agent, whether appointed by the Company or by such a court, shall be a
corporation organized and doing business under the laws of the United States or
of any state of the United States, in good standing, which is authorized under
such laws to exercise corporate trust or stockholder services powers and is
subject to supervision or examination by federal or state authority and which
has at the time of its appointment as Rights Agent a combined capital and
surplus of at least $50 million. After appointment, the successor Rights Agent
shall be vested with the same powers, rights, duties and responsibilities as if
it had been originally named as Rights Agent without further act or deed; but
the predecessor Rights Agent shall deliver and transfer to the successor Rights
Agent any property at the time held by it hereunder, and execute and deliver any
further assurance, conveyance, act or deed necessary for the purpose. Not later
than the effective date of any such appointment, the Company shall file notice
thereof in writing with the predecessor Rights Agent and each transfer agent of
the Preferred Shares and the Common Shares, and mail a notice thereof in writing
to the registered holders of the Rights Certificates. Failure to give any notice
provided for in this Section 21, however, or any defect

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      therein, shall not affect the legality or validity of the resignation or
      removal of the Rights Agent or the appointment of the successor Rights
      Agent, as the case may be."

is hereby amended in its entirety to read as follows:

            "The  Rights Agent or any successor Rights Agent may resign and be
      discharged from its duties under this Agreement upon thirty (30) days'
      notice (or, following the termination of the transfer agency relationship,
      if any, in effect between the Company and such Rights Agent or successor
      Rights Agent, upon ten (10) business days' notice) in writing mailed to
      the Company and to each transfer agent of the Preferred Shares and the
      Common Shares by registered or certified mail. The Company may remove the
      Rights Agent or any successor Rights Agent upon thirty (30) days' notice
      (or, following the termination of the transfer agency relationship, if
      any, in effect between the Company and such Rights Agent or successor
      Rights Agent, upon ten (10) business days' notice) in writing, mailed to
      the Rights Agent or successor Rights Agent, as the case may be, and to
      each transfer agent of the Preferred Shares and the Common Shares by
      registered or certified mail. If the Rights Agent shall resign or be
      removed or shall otherwise become incapable of acting, the Company shall
      appoint a successor to the Rights Agent. If the Company shall fail to make
      such appointment within a period of thirty (30) days (or, following the
      termination of the transfer agency relationship, if any, in effect between
      the Company and such Rights Agent or successor Rights Agent, of ten (10)
      business days) after giving notice of such removal or after it has been
      notified in writing of such resignation or incapacity by the resigning or
      incapacitated Rights Agent or by the holder of a Rights Certificate (who
      shall, with such notice, submit his or her Rights Certificate for
      inspection by the Company), then the Rights Agent or the registered holder
      of any Rights Certificate may apply to any court of competent jurisdiction
      for the appointment of a new Rights Agent. Any successor Rights Agent,
      whether appointed by the Company or by such a court, shall be a
      corporation organized and doing business under the laws of the United
      States or of any state of the United States, in good standing, which is
      authorized under such laws to exercise corporate trust or stockholder
      services powers and is subject to supervision or examination by federal or
      state authority and which has at the time of its appointment as Rights
      Agent a combined capital and surplus of at least $50 million. After
      appointment, the successor Rights Agent shall be vested with the same
      powers, rights, duties and responsibilities as if it had been originally
      named as Rights Agent without further act or deed; but the predecessor
      Rights Agent shall deliver and transfer to the successor Rights Agent any
      property at the time held by it hereunder, and execute and deliver any
      further assurance, conveyance, act or deed necessary for the purpose. Not
      later than the effective date of any such appointment, the Company shall
      file notice thereof in writing with the predecessor Rights Agent and each
      transfer agent of the Preferred Shares and the Common Shares, and mail a
      notice thereof in writing to the registered holders of the Rights
      Certificates. Failure to give any notice provided for in this Section 21,
      however, or any defect therein, shall not affect the legality or validity
      of the resignation or removal of the Rights Agent or the appointment of
      the successor Rights Agent, as the case may be."

      4.    Effectiveness. This Amendment shall be deemed effective as of April
22, 2004 as if executed on such date. Except as specifically amended hereby, all
of the terms of the Rights

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Agreement shall remain and continue in full force and effect and are hereby
confirmed in all respects.

      5.    Counterparts. This Amendment may be executed in counterparts and the
signature pages may be combined to create a document binding on all of the
parties hereto.

      6.    Miscellaneous. This Amendment shall be deemed to be a contract made
under the laws of the State of Delaware and for all purposes shall be governed
by and construed in accordance with the laws of such state applicable to
contracts to be made and performed entirely within such state. This Amendment
may be executed in any number of counterparts, each of such counterparts shall
for all purposes be deemed to be an original, and all such counterparts shall
together constitute but one and the same instrument. If any provision, covenant
or restriction of this Amendment is held by a court of competent jurisdiction or
other authority to be invalid, illegal or unenforceable, the remainder of the
terms, provisions, covenants and restrictions of this Amendment shall remain in
full force and effect and shall in no way be affected, impaired or invalidated.

                  (Remainder of Page Left Blank Intentionally)

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      IN WITNESS WHEREOF, the undersigned have caused their duly authorized
representatives to execute this Amendment as of the date first written above.

                                  CATALYST SEMICONDUCTOR, INC.

                                  By:  /s/ Gelu Voicu
                                       -----------------------------------------
                                       Gelu Voicu
                                       President and Chief Executive Officer

                                  EQUISERVE TRUST COMPANY N.A.

                                  By:  /s/ Carol Mulvey-Eori
                                       -----------------------------------------
                                       Name: Carol Mulvey-Eori
                                       Title: Managing Director