Exhibit 4.5
                                                                     -----------
                               AVANT! CORPORATION
                      2000 STOCK OPTION/STOCK ISSUANCE PLAN


                                   ARTICLE ONE
                               GENERAL PROVISIONS
                               ------------------


I.       PURPOSE OF THE PLAN
                  This 2000 Stock Option/Stock Issuance Plan is intended to
promote the interests of Avant! Corporation, a Delaware corporation, by
providing eligible persons with the opportunity to acquire a proprietary
interest, or otherwise increase their proprietary interest, in the Corporation
as an incentive for them to remain in the service of the Corporation.

                  Capitalized terms shall have the meanings assigned to such
terms in the attached Appendix.


II.      STRUCTURE OF THE PLAN
                  A. The Plan shall be divided into two separate equity
programs:

                           (i) the Discretionary Option Grant Program under
         which eligible persons may, at the discretion of the Plan
         Administrator, be granted options to purchase shares of Common Stock,
         and

                          (ii) the Stock Issuance Program under which eligible
         persons may, at the discretion of the Plan Administrator, be issued
         shares of Common Stock directly, either through the immediate purchase
         of such shares or as a bonus for services rendered to the Corporation
         (or any Parent or Subsidiary).

                  B. The provisions of Articles One and Four shall apply to all
equity programs under the Plan and shall accordingly govern the interests of all
persons under the Plan.


III.     ADMINISTRATION OF THE PLAN

                  A. The Board and the Primary Committee shall have the
authority to administer the Discretionary Option Grant and Stock Issuance
Programs with respect to Section 16 Insiders.

                  B. Administration of the Discretionary Option Grant and Stock
Issuance Programs with respect to all other persons eligible to participate in
these programs may, at the Board's discretion, be vested in the Primary
Committee or a Secondary Committee, or the Board may retain the power to
administer these programs with respect to all such persons. The members of the
Secondary Committee may be individuals who are Employees eligible to receive
discretionary option grants or direct stock issuances under the Plan or any
stock option, stock appreciation, stock bonus or other stock plan of the
Corporation (or any Parent or Subsidiary).

                  C. Members of the Primary Committee or any Secondary Committee
shall serve for such period of time as the Board may determine and shall be
subject to removal by the Board at any time. The Board may also at any time
terminate the functions of any Secondary Committee and reassume all powers and
authority previously delegated to such committee.

                  D. The Plan Administrator shall, within the scope of its
administrative functions under the Plan, have full power and authority (subject
to the provisions of the Plan) to establish such rules and regulations as it may
deem appropriate for proper administration of the Discretionary Option Grant and
Stock Issuance Programs and to make such determinations under, and issue such
interpretations of, the provisions of such programs and any outstanding options
or stock issuances thereunder as it may deem necessary or advisable. Decisions
of the Plan Administrator within the scope of its administrative functions under
the Plan shall be final and binding on all parties who have an interest in the
Discretionary Option Grant or Stock Issuance Program under its jurisdiction or
any option or stock issuance thereunder.

                  E. Service on the Primary Committee or the Secondary Committee
shall constitute service as a Board member, and members of each such committee
shall accordingly be entitled to full indemnification and reimbursement as Board
members for their service on such committee. No member of the Primary Committee
or the Secondary Committee shall be liable for any act or omission made in good
faith with respect to the Plan or any option grants or stock issuances under the
Plan.


IV.      ELIGIBILITY
                  A. The persons eligible to participate in the Discretionary
Option Grant and Stock Issuance Programs are as follows:

                           (i) Employees,

                          (ii) non-employee members of the Board or the board
         of directors of any Parent or Subsidiary, and

                         (iii) consultants and other independent advisors who
         provide services to the Corporation (or any Parent or Subsidiary).

                  B. The Plan Administrator shall, within the scope of its
administrative jurisdiction under the Plan, have full authority to determine (i)
with respect to the option grants under the Discretionary Option Grant Program,
which eligible persons are to receive option grants, the time or times when such
option grants are to be made, the number of shares to be covered by each such
grant, the time or times at which each option is to become exercisable, the
vesting schedule (if any) applicable to the option shares and the maximum term
for which the option is to remain outstanding and (ii) with respect to stock
issuances under the Stock Issuance Program, which eligible persons are to
receive stock issuances, the time or times when such issuances are to be made,
the number of shares to be issued to each Participant, the vesting schedule (if
any) applicable to the issued shares and the consideration to be paid by the
Participant for such shares.

                  C. The Plan Administrator shall have the absolute discretion
either to grant options in accordance with the Discretionary Option Grant
Program or to effect stock issuances in accordance with the Stock Issuance
Program.


V.       STOCK SUBJECT TO THE PLAN
                  A. The stock issuable under the Plan shall be shares of
authorized but unissued or reacquired Common Stock, including shares repurchased
by the Corporation on the open market. The number of shares of Common Stock that
may be issued over the term of the Plan shall be equal to the sum of (i)
2,000,000 shares of Common Stock, and (ii) additional shares of Common Stock, to
the extent authorized by the Board, that are reacquired by the Corporation in
the open market or in private transactions after the Effective Date. All options
granted under the Plan will be Non-Statutory Options..

                  B. The number of shares of Common Stock available for issuance
under the Plan shall automatically increase by 500,000 shares on the first day
of each calendar year during the term of the Plan, beginning with the 2001
calendar year.

                  C. Shares of Common Stock subject to outstanding options shall
be available for subsequent issuance under the Plan to the extent (i) the
options expire, terminate or are forfeited for any reason prior to exercise in
full, (ii) the options are canceled in accordance with the cancellation-regrant
provisions of Article Two, Section IV, or (iii) the shares acquired upon
exercise are repurchased by the Corporation pursuant to its repurchase rights
under the Plan All other shares issued under the Plan shall reduce on a
share-for-share basis the number of shares of Common Stock available for
subsequent issuance under the Plan. In addition, should the exercise price of an
option under the Plan be paid with shares of Common Stock or should shares of
Common Stock otherwise issuable under the Plan be withheld by the Corporation in
satisfaction of the withholding taxes incurred in connection with the exercise
of an option or the vesting of a stock issuance under the Plan, then the number
of shares of Common Stock available for issuance under the Plan shall be reduced
only by the net number of shares of Common Stock issued to the holder of such
option or stock issuance and not by the gross number of shares for which the
option is exercised or which vest under the stock issuance.

                  D. Should any change be made to the Common Stock by reason of
any stock split, stock dividend, recapitalization, combination of shares,
exchange of shares or other change affecting the outstanding Common Stock as a
class without the Corporation's receipt of consideration, appropriate
adjustments shall be made to (i) the maximum number and/or class of securities
issuable under the Plan, (ii) the number and/or class of securities for which
the share reserve is to increase automatically each year, (iii) the number
and/or class of securities for which any one person may be granted options,
separately exercisable stock appreciation rights and direct stock issuances over
the term of the Plan, and (iv) the number and/or class of securities and the
exercise price per share in effect under each outstanding option in order to
prevent the dilution or enlargement thereof. The adjustments determined by the
Plan Administrator shall be final, binding and conclusive.


                                   ARTICLE TWO
                       DISCRETIONARY OPTION GRANT PROGRAM
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I.       OPTION TERMS
                  Each option shall be evidenced by one or more documents in the
form approved by the Plan Administrator; provided, however, that each such
document shall comply with the terms specified below.

                  A. Exercise Price.

                           1. The exercise price per share shall be fixed by the
Plan Administrator but shall not be less than eighty-five percent (85%) of the
Fair Market Value per share of Common Stock on the option grant date.

                           2. The exercise price shall become immediately due
upon exercise of the option and shall, subject to the provisions of Section I of
Article Four and the documents evidencing the option, be payable in one or more
of the forms specified below:

                              (i) cash or check made payable to the Corporation,

                              (ii) shares of Common Stock held for the requisite
         period necessary to avoid a charge to the Corporation's earnings for
         financial reporting purposes and valued at Fair Market Value on the
         Exercise Date, or

                              (iii) to the extent the option is exercised for
         vested shares, through a special sale and remittance procedure pursuant
         to which the Optionee shall concurrently provide irrevocable written
         instructions to (a) a Corporation-designated brokerage firm to effect
         the immediate sale of the purchased shares and remit to the
         Corporation, out of the sale proceeds available on the settlement date,
         sufficient funds to cover the aggregate exercise price payable for the
         purchased shares plus all applicable Federal, state and local income
         and employment taxes required to be withheld by the Corporation by
         reason of such exercise and (b) the Corporation to deliver the
         certificates for the purchased shares directly to such brokerage firm
         in order to complete the sale transaction.

                  Except to the extent such sale and remittance procedure is
utilized, payment of the exercise price for the purchased shares must be made on
the Exercise Date.

                  B. Exercise and Term of Options. Each option shall be
exercisable at such time or times, during such period and for such number of
shares as shall be determined by the Plan Administrator and set forth in the
documents evidencing the option. However, no option shall have a term in excess
of ten (10) years measured from the option grant date.

                  C. Effect of Termination of Service.

                           1. The following provisions shall govern the exercise
of any options held by the Optionee at the time of cessation of Service or
death:

                              (i) Any option outstanding at the time of the
         Optionee's cessation of Service for any reason shall remain exercisable
         for such period of time thereafter as shall be determined by the Plan
         Administrator and set forth in the documents evidencing the option, but
         no such option shall be exercisable after the expiration of the option
         term.

                              (ii) Any option exercisable in whole or in part by
         the Optionee at the time of death may be subsequently exercised by the
         personal representative of the Optionee's estate or by the person or
         persons to whom the option is transferred pursuant to the Optionee's
         will or in accordance with the laws of descent and distribution.

                              (iii) During the applicable post-Service exercise
         period, the option may not be exercised in the aggregate for more than
         the number of vested shares for which the option is exercisable on the
         date of the Optionee's cessation of Service. Upon the expiration of the
         applicable exercise period or (if earlier) upon the expiration of the
         option term, the option shall terminate and cease to be outstanding for
         any vested shares for which the option has not been exercised. However,
         the option shall, immediately upon the Optionee's cessation of Service,
         terminate and cease to be outstanding to the extent it is not
         exercisable for vested shares on the date of such cessation of Service.

                              (iv) Should the Optionee's Service be terminated
         for Misconduct, then all outstanding options held by the Optionee shall
         terminate immediately and cease to be outstanding.

                              (v) In the event of a Corporate Transaction, the
         provisions of Section III of this Article Two shall govern the period
         for which the outstanding options are to remain exercisable following
         the Optionee's cessation of Service and shall supersede any provisions
         to the contrary in this section.

                           2. The Plan Administrator shall have the discretion,
exercisable either at the time an option is granted or at any time while the
option remains outstanding, to:

                              (i) extend the period of time for which the option
         is to remain exercisable following the Optionee's cessation of Service
         from the period otherwise in effect for that option to such greater
         period of time as the Plan Administrator shall deem appropriate, but in
         no event beyond the expiration of the option term, and/or

                              (ii) permit the option to be exercised, during the
         applicable post-Service exercise period, not only with respect to the
         number of vested shares of Common Stock for which such option is
         exercisable at the time of the Optionee's cessation of Service but also
         with respect to one or more additional installments in which the
         Optionee would have vested under the option had the Optionee continued
         in Service.

                  D. Stockholder Rights. The holder of an option shall have no
stockholder rights with respect to the shares subject to the option until such
person shall have exercised the option, paid the exercise price and become a
holder of record of the purchased shares.

                  E. Repurchase Rights. The Plan Administrator shall have the
discretion to grant options which are exercisable for unvested shares of Common
Stock. Should the Optionee cease Service while holding such unvested shares, the
Corporation shall have the right to repurchase, at the exercise price paid per
share, any or all of those unvested shares. The terms upon which such repurchase
right shall be exercisable (including the period and procedure for exercise and
the appropriate vesting schedule for the purchased shares) shall be established
by the Plan Administrator and set forth in the document evidencing such
repurchase right.

                  F. Limited Transferability of Options. During the lifetime of
the Optionee, the option shall be exercisable only by the Optionee unless the
option is assigned or transferred in accordance with this paragraph. Except as
otherwise determined by the Plan Administrator and incorporated in the documents
evidencing the option, an option shall not be assignable or transferable other
than by will or by the laws of descent and distribution following the Optionee's
death. Notwithstanding the foregoing, an option may be assigned in accordance
with the terms of a Qualified Domestic Relations Order. An assigned option may
only be exercised by the person or persons who acquire a proprietary interest in
the option in accordance with this paragraph. . The terms applicable to an
assigned option (or portion thereof) shall be the same as those in effect for
the option immediately prior to such assignment and shall be set forth in such
documents issued to the assignee as the Plan Administrator may deem appropriate.


II.      CORPORATE TRANSACTION/CHANGE IN CONTROL
                  A. In the event of any Corporate Transaction, each outstanding
option shall automatically accelerate so that each such option shall,
immediately prior to the effective date of the Corporate Transaction, become
fully exercisable for all of the shares of Common Stock at the time subject to
such option and may be exercised for any or all of those shares as fully-vested
shares of Common Stock. However, an outstanding option shall not so accelerate
if and to the extent: (i) such option is, in connection with the Corporate
Transaction, either to be assumed by the successor corporation (or parent
thereof) or to be replaced with a comparable option to purchase shares of the
capital stock of the successor corporation (or parent thereof), (ii) such option
is to be replaced with a cash incentive program of the successor corporation
which preserves the spread existing on the unvested option shares at the time of
the Corporate Transaction and provides for subsequent payout in accordance with
the same vesting schedule applicable to such option or (iii) the acceleration of
such option is subject to other limitations imposed by the Plan Administrator at
the time of the option grant. The determination of option comparability under
clause (i) above shall be made by the Plan Administrator, and its determination
shall be final, binding and conclusive.

                  B. All outstanding repurchase rights shall also terminate
automatically, and the shares of Common Stock subject to those terminated rights
shall immediately vest in full, in the event of any Corporate Transaction,
except to the extent: (i) those repurchase rights are to be assigned to the
successor corporation (or parent thereof) in connection with such Corporate
Transaction or (ii) such accelerated vesting is precluded by other limitations
imposed by the Plan Administrator at the time the repurchase right is issued.

                  C. Immediately following the consummation of the Corporate
Transaction, all outstanding options shall terminate and cease to be
outstanding, except to the extent assumed by the successor corporation (or
parent thereof).

                  D. Each option which is assumed in connection with a Corporate
Transaction shall be appropriately adjusted, immediately after such Corporate
Transaction, to apply to the number and class of securities which would have
been issuable to the Optionee in consummation of such Corporate Transaction had
the option been exercised immediately prior to such Corporate Transaction.
Appropriate adjustments shall also be made to (i) the number and class of
securities available for issuance under the Plan on both an aggregate and per
Optionee basis following the consummation of such Corporate Transaction and (ii)
the exercise price payable per share under each outstanding option, provided the
aggregate exercise price payable for such securities shall remain the same.

                  E. Any options which are assumed or replaced in the Corporate
Transaction and do not otherwise accelerate at that time, shall automatically
accelerate (and any of the Corporation's outstanding repurchase rights which do
not otherwise terminate at the time of the Corporate Transaction shall
automatically terminate and the shares of Common Stock subject to those
terminated rights shall immediately vest in full) in the event the Optionee's
Service should subsequently terminate by reason of an Involuntary Termination
within eighteen (18) months following the effective date of such Corporate
Transaction. Any options so accelerated shall remain exercisable for
fully-vested shares until the earlier of (i) the expiration of the option term
or (ii) the expiration of the one (1)-year period measured from the effective
date of the Involuntary Termination.

                  F. The Plan Administrator shall have the discretion,
exercisable either at the time the option is granted or at any time while the
option remains outstanding, to (i) provide for the automatic acceleration of one
or more outstanding options (and the automatic termination of one or more
outstanding repurchase rights with the immediate vesting of the shares of Common
Stock subject to those rights) upon the occurrence of a Change in Control or
(ii) condition any such option acceleration (and the termination of any
outstanding repurchase rights) upon the subsequent Involuntary Termination of
the Optionee's Service within a specified period following the effective date of
such Change in Control. Any options accelerated in connection with a Change in
Control shall remain fully exercisable until the expiration or sooner
termination of the option term.

                  G. The grant of options under the Discretionary Option Grant
Program shall in no way affect the right of the Corporation to adjust,
reclassify, reorganize or otherwise change its capital or business structure or
to merge, consolidate, dissolve, liquidate or sell or transfer all or any part
of its business or assets.


III.     CANCELLATION AND REGRANT OF OPTIONS
                  The Plan Administrator shall have the authority to effect, at
any time and from time to time, with the consent of the affected option holders,
the cancellation of any or all outstanding options under the Discretionary
Option Grant Program and to grant in substitution new options covering the same
or different number of shares of Common Stock but with an exercise price per
share based on the Fair Market Value per share of Common Stock on the new option
grant date.


IV.      STOCK APPRECIATION RIGHTS
                  A. The Plan Administrator shall have full power and authority
to grant to selected Optionees tandem stock appreciation rights and/or limited
stock appreciation rights.

                  B. The following terms shall govern the grant and exercise of
tandem stock appreciation rights:

                           (i) One or more Optionees may be granted the right,
         exercisable upon such terms as the Plan Administrator may establish, to
         elect between the exercise of the underlying option for shares of
         Common Stock and the surrender of that option in exchange for a
         distribution from the Corporation in an amount equal to the excess of
         (A) the Fair Market Value (on the option surrender date) of the number
         of shares in which the Optionee is at the time vested under the
         surrendered option (or surrendered portion thereof) over (B) the
         aggregate exercise price payable for such shares.

                           (ii) No such option surrender shall be effective
         unless it is approved by the Plan Administrator. If the surrender is so
         approved, then the distribution to which the Optionee shall be entitled
         may be made in shares of Common Stock valued at Fair Market Value on
         the option surrender date, in cash, or partly in shares and partly in
         cash, as the Plan Administrator shall in its sole discretion deem
         appropriate.

                           (iii) If the surrender of an option is rejected by
         the Plan Administrator, then the Optionee shall retain whatever rights
         the Optionee had under the surrendered option (or surrendered portion
         thereof) on the option surrender date and may exercise such rights at
         any time prior to the later of (A) five (5) business days after the
         receipt of the rejection notice or (B) the last day on which the option
         is otherwise exercisable in accordance with the terms of the documents
         evidencing such option, but in no event may such rights be exercised
         more than ten (10) years after the option grant date.

                  C. The following  terms shall govern the grant and exercise of
limited  stock  appreciation rights:

                           (i) One or more Section 16 Insiders may be granted
         limited stock appreciation rights with respect to their outstanding
         options.

                           (ii) Upon the occurrence of a Hostile Take-Over, each
         such individual holding one or more options with such a limited stock
         appreciation right in effect for at least six (6) months shall have the
         unconditional right (exercisable for a thirty (30)-day period following
         such Hostile Take-Over) to surrender each such option to the
         Corporation, to the extent the option is at the time exercisable for
         vested shares of Common Stock. In return for the surrendered option,
         the Optionee shall receive a cash distribution from the Corporation in
         an amount equal to the excess of (A) the Take-Over Price of the shares
         of Common Stock which are at the time vested under each surrendered
         option (or surrendered portion thereof) over (B) the aggregate exercise
         price payable for such shares. Such cash distribution shall be paid
         within five (5) days following the option surrender date.

                           (iii) Neither the approval of the Plan Administrator
         nor the consent of the Board shall be required in connection with such
         option surrender and cash distribution.

                           (iv) The balance of the option (if any) shall
         continue in full force and effect in accordance with the documents
         evidencing such option.


                                  ARTICLE THREE
                             STOCK ISSUANCE PROGRAM
                             ----------------------


I.       STOCK ISSUANCE TERMS
                  Shares of Common Stock may be issued under the Stock Issuance
Program through direct and immediate issuances without any intervening option
grants. Each such stock issuance shall be evidenced by a Stock Issuance
Agreement which complies with the terms specified below.

                  A. Purchase Price.

                           1. The purchase price per share shall be fixed by the
Plan Administrator, but shall not be less than eighty-five percent (85%) of the
Fair Market Value per share of Common Stock on the stock issuance date.

                           2. Subject to the provisions of Section I of Article
Five, shares of Common Stock may be issued under the Stock Issuance Program for
one or both of the following items of consideration which the Plan Administrator
may deem appropriate in each individual instance:

                           (i) cash or check made payable to the Corporation, or

                           (ii) past services rendered to the Corporation (or
         any Parent or Subsidiary).

                  B.       Vesting Provisions.

                           1. Shares of Common Stock issued under the Stock
Issuance Program may, in the discretion of the Plan Administrator, be fully and
immediately vested upon issuance or may vest in one or more installments over
the Participant's period of Service or upon attainment of specified performance
objectives. The elements of the vesting schedule applicable to any unvested
shares of Common Stock issued under the Stock Issuance Program, namely:

                           (i) the Service period to be completed by the
         Participant or the performance objectives to be attained,

                           (ii) the number of installments in which the shares
         are to vest,

                           (iii) the interval or intervals (if any) which are to
         lapse between installments, and

                           (iv) the effect which death, Permanent Disability or
         other event designated by the Plan Administrator is to have upon the
         vesting schedule,

shall be determined by the Plan Administrator and incorporated into the Stock
Issuance Agreement.

                           2. Any new, substituted or additional securities or
other property (including money paid other than as a regular cash dividend)
which the Participant may have the right to receive with respect to the
Participant's unvested shares of Common Stock by reason of any stock dividend,
stock split, recapitalization, combination of shares, exchange of shares or
other change affecting the outstanding Common Stock as a class without the
Corporation's receipt of consideration shall be issued subject to (i) the same
vesting requirements applicable to the Participant's unvested shares of Common
Stock and (ii) such escrow arrangements as the Plan Administrator shall deem
appropriate.

                           3. The Participant shall have full stockholder rights
with respect to any shares of Common Stock issued to the Participant under the
Stock Issuance Program, whether or not the Participant's interest in those
shares is vested. Accordingly, the Participant shall have the right to vote such
shares and to receive any regular cash dividends paid on such shares.

                           4. Should the Participant cease to remain in Service
while holding one or more unvested shares of Common Stock issued under the Stock
Issuance Program or should the performance objectives not be attained with
respect to one or more such unvested shares of Common Stock, then those shares
shall be immediately surrendered to the Corporation for cancellation, and the
Participant shall have no further stockholder rights with respect to those
shares. To the extent the surrendered shares were previously issued to the
Participant for consideration paid in cash or cash equivalent (including the
Participant's purchase-money indebtedness), the Corporation shall repay to the
Participant the cash consideration paid for the surrendered shares and shall
cancel the unpaid principal balance of any outstanding purchase-money note of
the Participant attributable to such surrendered shares.

                           5. The Plan Administrator may in its discretion waive
the surrender and cancellation of one or more unvested shares of Common Stock
(or other assets attributable thereto) which would otherwise occur upon the
cessation of the Participant's Service or the non-completion of the vesting
schedule applicable to such shares. Such waiver shall result in the immediate
vesting of the Participant's interest in the shares of Common Stock as to which
the waiver applies. Such waiver may be effected at any time, whether before or
after the Participant's cessation of Service or the attainment or non-attainment
of the applicable performance objectives.


II.      CORPORATE TRANSACTION/CHANGE IN CONTROL
                  A. All of the outstanding repurchase rights under the Stock
Issuance Program shall terminate automatically, and all the shares of Common
Stock subject to those terminated rights shall immediately vest in full, in the
event of any Corporate Transaction, except to the extent (i) those repurchase
rights are assigned to the successor corporation (or parent thereof) in
connection with such Corporate Transaction or (ii) such accelerated vesting is
precluded by other limitations imposed in the Stock Issuance Agreement.

                  B. Any repurchase rights that are assigned in the Corporate
Transaction shall automatically terminate, and all the shares of Common Stock
subject to those terminated rights shall immediately vest in full, in the event
the Participant's Service should subsequently terminate by reason of an
Involuntary Termination within eighteen (18) months following the effective date
of such Corporate Transaction.

                  C. The Plan Administrator shall have the discretion,
exercisable either at the time the unvested shares are issued or at any time
while the Corporation's repurchase right remains outstanding, to (i) provide for
the automatic termination of one or more outstanding repurchase rights and the
immediate vesting of the shares of Common Stock subject to those rights upon the
occurrence of a Change in Control or (ii) condition any such accelerated vesting
upon the subsequent Involuntary Termination of the Participant's Service within
a specified period following the effective date of such Change in Control.


III.     SHARE ESCROW/LEGENDS
                  Unvested shares may, in the Plan Administrator's discretion,
be held in escrow by the Corporation until the Participant's interest in such
shares vests or may be issued directly to the Participant with restrictive
legends on the certificates evidencing those unvested shares.


                                  ARTICLE FOUR
                                  MISCELLANEOUS
                                  -------------


I.       FINANCING
                  A. The Plan Administrator may permit any Optionee or
Participant to pay the option exercise price under the Discretionary Option
Grant Program or the purchase price for shares issued under the Stock Issuance
Program by delivering a promissory note payable in one or more installments. The
terms of any such promissory note (including the interest rate and the terms of
repayment) shall be established by the Plan Administrator in its sole
discretion. Promissory notes may be authorized with or without security or
collateral. In all events, the maximum credit available to the Optionee or
Participant may not exceed the sum of (i) the aggregate option exercise price or
purchase price payable for the purchased shares plus (ii) any Federal, state and
local income and employment tax liability incurred by the Optionee or the
Participant in connection with the option exercise or share purchase.

                  B. The Plan Administrator may, in its discretion, determine
that one or more such promissory notes shall be subject to forgiveness by the
Corporation in whole or in part upon such terms as the Plan Administrator may
deem appropriate.

II.      TAX WITHHOLDING
                  A. The Corporation's obligation to deliver shares of Common
Stock upon the exercise of options or stock appreciation rights or upon the
issuance or vesting of such shares under the Plan shall be subject to the
satisfaction of all applicable Federal, state and local income and employment
tax withholding requirements.

                  B. The Plan Administrator may, in its discretion, provide any
or all holders of options or unvested shares of Common Stock under the Plan with
the right to use shares of Common Stock in satisfaction of all or part of the
Taxes incurred by such holders in connection with the exercise of their options
or the vesting of their shares. Such right may be provided to any such holder in
either or both of the following formats:

                           (i) Stock Withholding: The election to have the
         Corporation withhold, from the shares of Common Stock otherwise
         issuable upon the exercise of such option or the vesting of such
         shares, a portion of those shares with an aggregate Fair Market Value
         equal to the percentage of the Taxes (not to exceed one hundred percent
         (100%)) designated by the holder.

                           (ii) Stock Delivery: The election to deliver to the
         Corporation, at the time the option is exercised or the shares vest,
         one or more shares of Common Stock previously acquired by such holder
         (other than in connection with the option exercise or share vesting
         triggering the Taxes) with an aggregate Fair Market Value equal to the
         percentage of the Taxes (not to exceed one hundred percent (100%))
         designated by the holder.


III.     EFFECTIVE DATE AND TERM OF THE PLAN
                  A. The Plan shall become effective on the Effective Date.

                  B. The Plan shall remain in effect until it is terminated. The
Board may terminate the Plan at any time and for any reason, provided, however,
that upon such Plan termination, all options, stock appreciation rights and
unvested stock issuances outstanding on such date shall thereafter continue to
have force and effect in accordance with the provisions of the documents
evidencing such options or issuances.


IV.      AMENDMENT OF THE PLAN
                  A. The Board shall have complete and exclusive power and
authority to amend or modify the Plan in any or all respects. However, no such
amendment or modification shall adversely affect the rights and obligations with
respect to options, stock appreciation rights or unvested stock issuances at the
time outstanding under the Plan, unless the Optionee or the Participant consents
to such amendment or modification.

                  B. Options to purchase shares of Common Stock may be granted
under the Discretionary Option Grant Program and shares of Common Stock may be
issued under the Stock Issuance Program that are in each instance in excess of
the number of shares then available for issuance under the Plan, provided any
excess shares actually issued under those programs are held in escrow until
there is obtained approval by the Board of an amendment sufficiently increasing
the number of shares of Common Stock available for issuance under the Plan. If
such approval is not obtained within twelve (12) months after the date the first
such excess issuances are made, then (i) any unexercised options granted on the
basis of such excess shares shall terminate and cease to be outstanding and (ii)
the Corporation shall promptly refund to the Optionees and the Participants the
exercise or purchase price paid for any excess shares issued under the Plan and
held in escrow, together with interest (at the applicable Short Term Federal
Rate) for the period the shares were held in escrow, and such shares shall
thereupon be automatically canceled and cease to be outstanding.


V.       USE OF PROCEEDS
                  Any cash proceeds received by the Corporation from the sale of
shares of Common Stock under the Plan shall be used for general corporate
purposes.


VI.      REGULATORY APPROVALS
                  A. The implementation of the Plan, the granting of any option
or stock appreciation right under the Plan and the issuance of any shares of
Common Stock (i) upon the exercise of any option or stock appreciation right or
(ii) under the Stock Issuance Program shall be subject to the Corporation's
procurement of all approvals and permits required by regulatory authorities
having jurisdiction over the Plan, the options and stock appreciation rights
granted under it and the shares of Common Stock issued pursuant to it.

                  B. No shares of Common Stock or other assets shall be issued
or delivered under the Plan unless and until there shall have been compliance
with all applicable requirements of Federal and state securities laws, including
the filing and effectiveness of the Form S-8 registration statement for the
shares of Common Stock issuable under the Plan, and all applicable listing
requirements of any stock exchange (or the Nasdaq National Market, if
applicable) on which Common Stock is then listed for trading.


VII.     NO EMPLOYMENT/SERVICE RIGHTS
                  Nothing in the Plan shall confer upon the Optionee or the
Participant any right to continue in Service for any period of specific duration
or interfere with or otherwise restrict in any way the rights of the Corporation
(or any Parent or Subsidiary employing or retaining such person) or of the
Optionee or the Participant, which rights are hereby expressly reserved by each,
to terminate such person's Service at any time for any reason, with or without
cause.

<PAGE>
                                    APPENDIX



                  The following definitions shall be in effect under the Plan:

                  A. Board shall mean the Corporation's Board of Directors.

                  B. Change in Control shall mean a change in ownership or
control of the Corporation effected through either of the following
transactions:

                           (i) the acquisition, directly or indirectly, by any
                  person or related group of persons (other than the Corporation
                  or a person that directly or indirectly controls, is
                  controlled by, or is under common control with, the
                  Corporation), of beneficial ownership (within the meaning of
                  Rule 13d-3 of the 1934 Act) of securities possessing more than
                  fifty percent (50%) of the total combined voting power of the
                  Corporation's outstanding securities pursuant to a tender or
                  exchange offer made directly to the Corporation's stockholders
                  which the Board does not recommend such stockholders to
                  accept, or

                           (ii) a change in the composition of the Board over a
                  period of thirty-six (36) consecutive months or less such that
                  a majority of the Board members ceases, by reason of one or
                  more contested elections for Board membership, to be comprised
                  of individuals who either (A) have been Board members
                  continuously since the beginning of such period or (B) have
                  been elected or nominated for election as Board members during
                  such period by at least a majority of the Board members
                  described in clause (A) who were still in office at the time
                  the Board approved such election or nomination.

                  C. Code shall mean the Internal Revenue Code of 1986, as
amended.

                  D. Common Stock shall mean the Corporation's common stock.

                  E. Corporate Transaction shall mean either of the following
stockholder-approved transactions to which the Corporation is a party:

                           (i) a merger or consolidation in which securities
                  possessing more than fifty percent (50%) of the total combined
                  voting power of the Corporation's outstanding securities are
                  transferred to a person or persons different from the persons
                  holding those immediately prior to such transaction; or

                           (ii) the sale, transfer or other disposition of all
                  or substantially all of the Corporation's assets in complete
                  liquidation or dissolution of the Corporation.

                  F. Corporation shall mean Avant! Corporation, a Delaware
corporation.

                  G. Discretionary Option Grant Program shall mean the
discretionary option grant program in effect under the Plan.

                  H. Domestic Relations Order shall mean any judgment, decree or
order (including approval of a property settlement agreement) which provides or
otherwise conveys, pursuant to applicable State domestic relations laws
(including community property laws), marital property rights to any spouse or
former spouse of the Optionee.

                  I. Effective Date shall mean the date on which the Plan is
adopted by the Board.

                  J. Eligible Director shall mean a non-employee Board member
eligible to participate in the Option Grant Program in accordance with the
eligibility provisions of Article One.

                  K. Employee shall mean an individual who is in the employ of
the Corporation (or any Parent or Subsidiary), subject to the control and
direction of the employer entity as to both the work to be performed and the
manner and method of performance.

                  L. Exercise Date shall mean the date on which the Corporation
shall have received written notice of the option exercise.

                  M. Fair Market Value per share of Common Stock on any relevant
date shall be determined in accordance with the following provisions:

                           (i) If the Common Stock is at the time traded on the
                  Nasdaq National Market, then the Fair Market Value shall be
                  the closing price per share of Common Stock on the date in
                  question, as such price is reported by the National
                  Association of Securities Dealers on the Nasdaq National
                  Market or any successor system. If there is no closing price
                  for the Common Stock on the date in question, then the Fair
                  Market Value shall be the closing price on the last preceding
                  date for which such quotation exists.

                           (ii) If the Common Stock is at the time listed on any
                  Stock Exchange, then the Fair Market Value shall be the
                  closing selling price per share of Common Stock on the date in
                  question on the Stock Exchange determined by the Plan
                  Administrator to be the primary market for the Common Stock,
                  as such price is officially quoted in the composite tape of
                  transactions on such exchange. If there is no closing selling
                  price for the Common Stock on the date in question, then the
                  Fair Market Value shall be the closing selling price on the
                  last preceding date for which such quotation exists.

                  N. Hostile Take-Over shall mean a change in ownership of the
Corporation effected through the following transaction:

                           (i) the acquisition, directly or indirectly, by any
                  person or related group of persons (other than the Corporation
                  or a person that directly or indirectly controls, is
                  controlled by, or is under common control with, the
                  Corporation) of beneficial ownership (within the meaning of
                  Rule 13d-3 of the 1934 Act) of securities possessing more than
                  fifty percent (50%) of the total combined voting power of the
                  Corporation's outstanding securities pursuant to a tender or
                  exchange offer made directly to the Corporation's stockholders
                  which the Board does not recommend such stockholders to
                  accept, and

                           (ii) more than fifty percent (50%) of the securities
                  so acquired are accepted from persons other than Section 16
                  Insiders.

                  O. Involuntary Termination shall mean the termination of the
Service of any individual which occurs by reason of:

                           (i) such individual's involuntary dismissal or
                  discharge by the Corporation for reasons other than
                  Misconduct, or

                           (ii) such individual's voluntary resignation
                  following (A) a change in his or her position with the
                  Corporation which materially reduces his or her level of
                  responsibility, (B) a reduction in his or her level of
                  compensation (including base salary, fringe benefits and any
                  non-discretionary and objective-standard incentive payment or
                  bonus award) by more than fifteen percent (15%) or (C) a
                  relocation of such individual's place of employment by more
                  than fifty (50) miles, provided and only if such change,
                  reduction or relocation is effected by the Corporation without
                  the individual's consent.

                  P. Misconduct shall mean the commission of any act of fraud,
embezzlement or dishonesty by the Optionee or Participant, any unauthorized use
or disclosure by such person of confidential information or trade secrets of the
Corporation (or any Parent or Subsidiary), or any other intentional misconduct
by such person adversely affecting the business or affairs of the Corporation
(or any Parent or Subsidiary) in a material manner. The foregoing definition
shall not be deemed to be inclusive of all the acts or omissions which the
Corporation (or any Parent or Subsidiary) may consider as grounds for the
dismissal or discharge of any Optionee, Participant or other person in the
Service of the Corporation (or any Parent or Subsidiary).

                  Q. 1934 Act shall mean the Securities Exchange Act of 1934, as
amended.

                  R. Non-Statutory Options shall mean options not intended to
satisfy the requirements of Code Section 422.

                  S. Optionee shall mean any person to whom an option is granted
under the Discretionary Option Grant Program.

                  T. Parent shall mean any corporation (other than the
Corporation) in an unbroken chain of corporations ending with the Corporation,
provided each corporation in the unbroken chain (other than the Corporation)
owns, at the time of the determination, stock possessing fifty percent (50%) or
more of the total combined voting power of all classes of stock in one of the
other corporations in such chain.

                  U. Participant shall mean any person who is issued shares of
Common Stock under the Stock Issuance Program.

                  V. Permanent Disability or Permanently Disabled shall mean the
inability of the Optionee or the Participant to engage in any substantial
gainful activity by reason of any medically determinable physical or mental
impairment expected to result in death or to be of continuous duration of twelve
(12) months or more.

                  W. Plan shall mean the Corporation's 2000 Stock Option/Stock
Issuance Plan, as set forth in this document.

                  X. Plan Administrator shall mean the particular entity,
whether the Primary Committee, the Board or the Secondary Committee, which is
authorized to administer the Discretionary Option Grant and Stock Issuance
Programs with respect to one or more classes of eligible persons, to the extent
such entity is carrying out its administrative functions under those programs
with respect to the persons under its jurisdiction.

                  Y. Primary Committee shall mean a committee of two (2) or more
non-employee Board members appointed by the Board to administer the
Discretionary Option Grant and Stock Issuance Programs with respect to Section
16 Insiders.

                  Z. Qualified Domestic Relations Order shall mean a Domestic
Relations Order which substantially complies with the requirements of Code
Section 414(p). The Plan Administrator shall have the sole discretion to
determine whether a Domestic Relations Order is a Qualified Domestic Relations
Order.

                  AA. Secondary Committee shall mean a committee of one (1) or
more Board members appointed by the Board to administer the Discretionary Option
Grant and Stock Issuance Programs with respect to eligible persons other than
Section 16 Insiders.

                  BB. Section 16 Insider shall mean an officer or director of
the Corporation subject to the short-swing profit liabilities of Section 16 of
the 1934 Act.

                  CC. Service shall mean the provision of services to the
Corporation (or any Parent or Subsidiary) by a person in the capacity of an
Employee, a non-employee member of the board of directors or a consultant or
independent advisor, except to the extent otherwise specifically provided in the
documents evidencing the option grant or stock issuance.

                  DD. Stock Exchange shall mean either the American Stock
Exchange or the New York Stock Exchange.

                  EE. Stock Issuance Agreement shall mean the agreement entered
into by the Corporation and the Participant at the time of issuance of shares of
Common Stock under the Stock Issuance Program.

                  FF. Stock Issuance Program shall mean the stock issuance
program in effect under the Plan.

                  GG. Subsidiary shall mean any corporation (other than the
Corporation) in an unbroken chain of corporations beginning with the
Corporation, provided each corporation (other than the last corporation) in the
unbroken chain owns, at the time of the determination, stock possessing fifty
percent (50%) or more of the total combined voting power of all classes of stock
in one of the other corporations in such chain.

                  HH. Take-Over Price shall mean the greater of (i) the Fair
Market Value per share of Common Stock on the date the option is surrendered to
the Corporation in connection with a Hostile Take-Over or (ii) the highest
reported price per share of Common Stock paid by the tender offeror in effecting
such Hostile Take-Over.

                  II. Taxes shall mean the Federal, state and local income and
employment tax liabilities incurred by the holder of Non-Statutory Options or
unvested shares of Common Stock in connection with the exercise of such holder's
options or the vesting of his or her shares.