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                                                                    Exhibit 10.4


                             2000 STOCK OPTION PLAN
                               FORM OF RESTRICTED
                            STOCK PURCHASE AGREEMENT

         THIS AGREEMENT is made between ____________________________________
(the "Purchaser") and Monolithic System Technology, Inc., a California
corporation (the "Company"), as of __________________, 20__.

                                    RECITALS

         Pursuant to the exercise of the stock option granted to the Purchaser
under the Company's 2000 Stock Option Plan and pursuant to the Stock Option
Agreement (the "Option Agreement") dated ___________, 20___ by and between the
Company and the Purchaser with respect to such grant, which Option Agreement is
hereby incorporated by reference, the Purchaser has elected to purchase
_________ shares of the Company's Common Stock of which ________ shares are not,
as of the date hereof, vested under the vesting schedule set forth in the Notice
of Option Grant attached to the Option Agreement, shares of the Company's Common
Stock that are not vested under said vesting schedule as of the date of
determination are referred to in this Agreement as "Unvested Shares." The
Unvested Shares and the shares subject to the Option Agreement that have become
vested are sometimes collectively referred to herein as the "Shares."

         As required by the Option Agreement, as a condition to the Purchaser's
election to exercise the option, the Purchaser must execute and deliver this
Restricted Stock Purchase Agreement, which sets forth the rights and obligations
of the parties with respect to Shares acquired upon exercise of the Option.

         2.       REPURCHASE OPTION.

                  (a) If the Purchaser's employment or consulting relationship
with the Company is terminated for any reason, including without limitation, for
cause or on the death or disability of the Purchaser (a "Termination"), the
Company shall have the right and option to purchase from the Purchaser, or the
Purchaser's personal representative, as the case may be, all or any part of the
Purchaser's Unvested Shares as of the date of such termination at the price paid
by the Purchaser for such Unvested Shares (the "Repurchase Option").

                  (b) Upon the occurrence of a Termination, the Company may
exercise its Repurchase Option by delivering personally or by registered mail,
to the Purchaser (or his transferee or legal representative, as the case may
be), within ninety (90) days of the Termination, a notice in writing indicating
the Company's intention to exercise the Repurchase Option and setting forth a
date for closing not later than thirty (30) days from the mailing of such
notice. The closing shall take place at the Company's office. At the closing,
the holder of the certificates for the Unvested Shares being transferred shall
deliver the stock certificate or

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certificates evidencing the Unvested Shares, and the Company shall deliver the
purchase price therefor.

                  (c) If the Company does not elect to exercise the Repurchase
Option conferred above by giving the requisite notice within ninety (90) days
following the termination, the Repurchase Option shall terminate.

         3.       TRANSFERABILITY OF THE SHARES; ESCROW.

                  (a) The Purchaser hereby authorizes and directs the secretary
of the Company, or such other person designated by the Company, to transfer the
Unvested Shares from the Purchaser to the Company.

                  (b) To insure the availability for delivery of the Purchaser's
Unvested Shares upon repurchase by the Company pursuant to the Repurchase Option
under Section 1, the Purchaser hereby appoints the secretary, or any other
person designated by the Company as escrow agent (either party, the "Escrow
Agent"), as its attorney-in-fact to sell, assign and transfer unto the Company
such Unvested Shares, if any, repurchased by the Company pursuant to the
Repurchase Option. The Purchaser shall, upon execution of this Agreement,
deliver and deposit with the Escrow Agent the share certificates representing
the Unvested Shares, together with the stock assignment duly endorsed in blank,
attached hereto as EXHIBIT C-2. The Unvested Shares and stock assignment shall
be held by the Escrow Agent in escrow, pursuant to the Joint Escrow Instructions
of the Company and the Purchaser attached as EXHIBIT C-3 hereto, until the
Company exercises its purchase right as provided in Section 1, until such
Unvested Shares are vested, or until such time as this Agreement no longer is in
effect. Upon the vesting of all of the Unvested Shares, the Escrow Agent shall
promptly deliver to the Purchaser the certificate or certificates representing
such Shares in the Escrow Agent's possession belonging to the Purchaser, and the
Escrow Agent shall be discharged of all further obligations hereunder; provided,
however, that the Escrow Agent shall nevertheless retain such certificate or
certificates as Escrow Agent if so required pursuant to other restrictions
imposed pursuant to this Agreement.

                  (c) Neither the Company nor the Escrow Agent shall be liable
for any act it may do or omit to do with respect to holding the Shares in escrow
and while acting in good faith and in the exercise of its judgment.

                  (d) Transfer or sale of the Shares is subject to restrictions
on transfer imposed by any applicable state and federal securities laws. Any
transferee shall hold such Shares subject to all the provisions hereof and the
Exercise Notice executed by the Purchaser with respect to any Unvested Shares
and shall acknowledge the same by signing a copy of this Agreement.

         3. MARKET STAND-OFF AGREEMENT. The Purchaser hereby agrees that, if so
requested by the Company or any representative of the underwriters in connection
with any registration of the offering of any securities of the Company under the
Securities Act, the Purchaser shall not sell or otherwise transfer any Shares or
other securities of the Company during the 180-day period following the
effective date of a registration statement of the Company filed under the
Securities Act; [provided, however, that such restriction shall only apply to
the first registration


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statement of the Company to become effective under the Securities Act which
include securities to be sold on behalf of the Company to the public in an
underwritten public offering under the Securities Act.] The Company may impose
stop-transfer instructions with respect to securities subject to the foregoing
restrictions until the end of such 180-day period.

         4. OWNERSHIP, VOTING RIGHTS, DUTIES. This Agreement shall not affect in
any way the ownership, voting rights or other rights or duties of the Purchaser,
except as specifically provided herein.

         5. LEGENDS. The share certificate evidencing the Shares issued
hereunder shall be endorsed with the following legends (in addition to any
legend required under applicable state securities laws):

         THE SECURITIES REPRESENTED HEREBY HAVE NOT BEEN REGISTERED UNDER THE
         SECURITIES ACT OF 1933 (THE "ACT") AND MAY NOT BE OFFERED, SOLD OR
         OTHERWISE TRANSFERRED, PLEDGED OR HYPOTHECATED UNLESS AND UNTIL
         REGISTERED UNDER THE ACT OR SUCH OFFER, SALE OR TRANSFER, PLEDGE OR
         HYPOTHECATION IS IN COMPLIANCE THEREWITH.

         THE SHARES REPRESENTED BY THIS CERTIFICATE ARE SUBJECT TO CERTAIN
         RESTRICTIONS ON TRANSFER AND REPURCHASE OPTION HELD BY THE ISSUER OR
         ITS ASSIGNEE(S) AS SET FORTH IN A RESTRICTED STOCK PURCHASE AGREEMENT
         BETWEEN THE ISSUER AND THE ORIGINAL HOLDER OF THESE SHARES, A COPY OF
         WHICH MAY BE OBTAINED AT THE PRINCIPAL OFFICE OF THE ISSUER. SUCH
         TRANSFER RESTRICTIONS AND RIGHT OF REPURCHASE ARE BINDING ON
         TRANSFEREES OF THESE SHARES.

         6. ADJUSTMENT FOR STOCK SPLIT. All references to the number of Shares
and the purchase price of the Shares in this Agreement shall be appropriately
adjusted to reflect any stock split, stock dividend or other change in the
Shares which may be made by the Company after the date of this Agreement.

         7. NOTICES. Notices required hereunder shall be given in person or by
registered mail to the address of the Purchaser shown on the records of the
Company, and to the Company, at their respective principal executive offices.

         8. SURVIVAL OF TERMS. This Agreement shall apply to and bind the
Purchaser and the Company and their respective permitted assignees and
transferees, heirs, legatees, executors, administrators and legal successors.

         9. SECTION 83(b) ELECTIONS.

                  (a) ELECTION FOR UNVESTED SHARES PURCHASED PURSUANT TO
NONQUALIFIED STOCK OPTIONS. The Purchaser hereby acknowledges that he or she has
been informed that, with respect

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to the exercise of a nonqualified stock option for Unvested Shares, that unless
an election is filed by the Purchaser with the Internal Revenue Service and, if
necessary, the proper state taxing authorities, WITHIN 30 DAYS of the purchase
of the Shares, electing pursuant to Section 83(b) of the Code (and similar state
tax provisions if applicable) to be taxed currently on any difference between
the purchase price of the Shares and their Fair Market Value on the date of
purchase, there will be a recognition of taxable income to the Optionee,
measured by the excess, if any, of the fair market value of the Shares, at the
time the Company's Repurchase Option lapses over the purchase price for the
Shares. The Optionee represents that the Optionee has consulted any tax
consultant(s) the Optionee deems advisable in connection with the purchase of
the Shares or the filing of the Election under Section 83(b) and similar tax
provisions. A form of Election under Section 83(b) is attached hereto as EXHIBIT
C-4 for reference.

               (b) ELECTION FOR UNVESTED SHARES PURCHASED PURSUANT TO INCENTIVE
STOCK OPTIONS. The Purchaser hereby acknowledges that he or she has been
informed that, with respect to the exercise of an incentive stock option for
Unvested Shares, that unless an election is filed by the Purchaser with the
Internal Revenue Service and, if necessary, the proper state taxing authorities,
WITHIN 30 DAYS of the purchase of the Shares, electing pursuant to Section 83(b)
of the Code (and similar state tax provisions if applicable) to be taxed
currently on any difference between the purchase price of the Shares and their
Fair Market Value on the date of purchase, there will be a recognition of income
to the Optionee, for alternative minimum tax purposes, measured by the excess,
if any, of the fair market value of the Shares, at the time the Company's
Repurchase Option lapses over the purchase price for the Shares. The Optionee
represents that the Optionee has consulted any tax consultant(s) the Optionee
deems advisable in connection with the purchase of the Shares or the filing of
the Election under Section 83(b) and similar tax provisions. A form of Election
under Section 83(b) for alternative minimum tax purposes is attached hereto as
EXHIBIT C-5 for reference.

         PURCHASER ACKNOWLEDGES THAT IT IS PURCHASER'S SOLE RESPONSIBILITY AND
         NOT THE COMPANY'S TO FILE TIMELY THE ELECTION UNDER SECTION 83(b), EVEN
         IF PURCHASER REQUESTS THE COMPANY OR ITS REPRESENTATIVE TO MAKE THIS
         FILING ON PURCHASER'S BEHALF.

         10. REPRESENTATIONS. The Purchaser has reviewed with his own tax
advisors the federal, state, local and foreign tax consequences of this
investment and the transactions contemplated by this Agreement. The Purchaser is
relying solely on such advisors and not on any statements or representations of
the Company or any of its agents. The Purchaser understands that he (and not the
Company) shall be responsible for his own tax liability that may arise as a
result of this investment or the transactions contemplated by this Agreement.

         11. GOVERNING LAW. This Agreement shall be governed by and construed
and enforced in accordance with applicable state laws.

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         The Purchaser represents that he has read this Agreement and is
familiar with its terms and provisions. The Purchaser hereby agrees to accept as
binding, conclusive and final all decisions or interpretations of the Board upon
any questions arising under this Agreement.

                                      * * *


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         IN WITNESS WHEREOF, this Restricted Stock Purchase Agreement is deemed
made as of the date first set forth above.

                                    "COMPANY"

                                    MONOLITHIC SYSTEM TECHNOLOGY, INC.

                                    By:
                                       -------------------------------------
                                    Title:
                                          ----------------------------------

                                   "PURCHASER"

                                    ----------------------------------------
                                                  (Signature)

                                    ----------------------------------------
                                                  (Print Name)

                                    Address:
                                            --------------------------------

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

                                    Soc. Sec. No.:
                                                  --------------------------

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