<PAGE>

                                                                    EXHIBIT 10.5

                       VOLTERRA SEMICONDUCTOR CORPORATION

                 2004 NON-EMPLOYEE DIRECTORS' STOCK OPTION PLAN

                              ADOPTED: MAY 17, 2004
                 APPROVED BY STOCKHOLDERS: _______________, 2004

1.    PURPOSES.

      (a)   ELIGIBLE OPTION RECIPIENTS. The persons eligible to receive Options
are the Non-Employee Directors of the Company.

      (b)   AVAILABLE OPTIONS. The purpose of the Plan is to provide a means by
which Non-Employee Directors may be given an opportunity to benefit from
increases in value of the Common Stock through the granting of Nonstatutory
Stock Options.

      (c)   GENERAL PURPOSE. The Company, by means of the Plan, seeks to retain
the services of its Non-Employee Directors, to secure and retain the services of
new Non-Employee Directors and to provide incentives for such persons to exert
maximum efforts for the success of the Company and its Affiliates.

2.    DEFINITIONS.

      As used in the Plan, the following definitions shall apply to the
capitalized terms indicated below:

      (a)   "ACCOUNTANT" means the independent public accountants of the
Company.

      (b)   "AFFILIATE" means any parent corporation or subsidiary corporation
of the Company, whether now or hereafter existing, as those terms are defined in
Sections 424(e) and (f), respectively, of the Code.

      (c)   "ANNUAL GRANT" means an Option granted annually to all Non-Employee
Directors who meet the specified criteria pursuant to Section 6(b).

      (d)   "ANNUAL MEETING" means the annual meeting of the stockholders of the
Company.

      (e)   "BOARD" means the Board of Directors of the Company.

      (f)   "CAPITALIZATION ADJUSTMENT" has the meaning ascribed to that term in
Section 11(a).

      (g)   "CHANGE IN CONTROL" means the occurrence, in a single transaction or
in a series of related transactions, of any one or more of the following events:

                                       1.

<PAGE>

                  (i)   any Exchange Act Person becomes the Owner, directly or
indirectly, of securities of the Company representing more than fifty percent
(50%) of the combined voting power of the Company's then outstanding securities
other than by virtue of a merger, consolidation or similar transaction.
Notwithstanding the foregoing, a Change in Control shall not be deemed to occur
(A) on account of the acquisition of securities of the Company by an investor,
any affiliate thereof or any other Exchange Act Person from the Company in a
transaction or series of related transactions the primary purpose of which is to
obtain financing for the Company through the issuance of equity securities or
(B) solely because the level of Ownership held by any Exchange Act Person (the
"Subject Person") exceeds the designated percentage threshold of the outstanding
voting securities as a result of a repurchase or other acquisition of voting
securities by the Company reducing the number of shares outstanding, provided
that if a Change in Control would occur (but for the operation of this sentence)
as a result of the acquisition of voting securities by the Company, and after
such share acquisition, the Subject Person becomes the Owner of any additional
voting securities that, assuming the repurchase or other acquisition had not
occurred, increases the percentage of the then outstanding voting securities
Owned by the Subject Person over the designated percentage threshold, then a
Change in Control shall be deemed to occur;

                  (ii)  there is consummated a merger, consolidation or similar
transaction involving (directly or indirectly) the Company and, immediately
after the consummation of such merger, consolidation or similar transaction, the
stockholders of the Company immediately prior thereto do not Own, directly or
indirectly, either (A) outstanding voting securities representing more than
fifty percent (50%) of the combined outstanding voting power of the surviving
Entity in such merger, consolidation or similar transaction or (B) more than
fifty percent (50%) of the combined outstanding voting power of the parent of
the surviving Entity in such merger, consolidation or similar transaction, in
each case in substantially the same proportions as their Ownership of the
outstanding voting securities of the Company immediately prior to such
transaction;

                  (iii) the stockholders of the Company approve or the Board
approves a plan of complete dissolution or liquidation of the Company, or a
complete dissolution or liquidation of the Company shall otherwise occur;

                  (iv)  there is consummated a sale, lease, license or other
disposition of all or substantially all of the consolidated assets of the
Company and its Subsidiaries, other than a sale, lease, license or other
disposition of all or substantially all of the consolidated assets of the
Company and its Subsidiaries to an Entity, more than fifty percent (50%) of the
combined voting power of the voting securities of which are Owned by
stockholders of the Company in substantially the same proportions as their
Ownership of the outstanding voting securities of the Company immediately prior
to such sale, lease, license or other disposition; or

                  (v)   individuals who, on the date this Plan is adopted by the
Board, are members of the Board (the "Incumbent Board") cease for any reason to
constitute at least a majority of the members of the Board; provided, however,
that if the appointment or election (or nomination for election) of any new
Board member was approved or recommended by a majority vote of the members of
the Incumbent Board then still in office, such new member shall, for purposes of
this Plan, be considered as a member of the Incumbent Board.

                                       2.

<PAGE>

      The term Change in Control shall not include a sale of assets, merger or
other transaction effected exclusively for the purpose of changing the domicile
of the Company.

      Notwithstanding the foregoing or any other provision of this Plan, the
definition of Change in Control (or any analogous term) in an individual written
agreement between the Company or any Affiliate and the Optionholder shall
supersede the foregoing definition with respect to Options subject to such
agreement (it being understood, however, that if no definition of Change in
Control or any analogous term is set forth in such an individual written
agreement, the foregoing definition shall apply).

      (h)   "CODE" means the Internal Revenue Code of 1986, as amended.

      (i)   "COMMON STOCK" means the common stock of the Company.

      (j)   "COMPANY" means Volterra Semiconductor Corporation, a Delaware
corporation.

      (k)   "CONSULTANT" means any person, including an advisor, who (i) is
engaged by the Company or an Affiliate to render consulting or advisory services
and is compensated for such services or (ii) is serving as a member of the Board
of Directors of an Affiliate and is compensated for such services. However,
service solely as a Director, or payment of a fee for such services, shall not
cause a Director to be considered a "Consultant" for purposes of the Plan.

      (l)   "CONTINUOUS SERVICE" means that the Optionholder's service with the
Company or an Affiliate, whether as an Employee, Director or Consultant, is not
interrupted or terminated. A change in the capacity in which the Optionholder
renders service to the Company or an Affiliate as an Employee, Consultant or
Director or a change in the entity for which the Optionholder renders such
service, provided that there is no interruption or termination of the
Optionholder's service with the Company or an Affiliate, shall not terminate an
Optionholder's Continuous Service. For example, a change in status from a
Non-Employee Director of the Company to a Consultant of an Affiliate or an
Employee of the Company will not constitute an interruption of Continuous
Service. The Board or the chief executive officer of the Company, in that
party's sole discretion, may determine whether Continuous Service shall be
considered interrupted in the case of any leave of absence approved by that
party, including sick leave, military leave or any other personal leave.
Notwithstanding the foregoing, a leave of absence shall be treated as Continuous
Service for purposes of vesting in an Option only to such extent as may be
provided in the Company's leave of absence policy or in the written terms of the
Optionholder's leave of absence.

      (m)   "CORPORATE TRANSACTION" means the occurrence, in a single
transaction or in a series of related transactions, of any one or more of the
following events:

            (i)   a sale or other disposition of all or substantially all, as
determined by the Board in its sole discretion, of the consolidated assets of
the Company and its Subsidiaries;

            (ii)  a sale or other disposition of at least ninety percent (90%)
of the outstanding securities of the Company;

                                       3.

<PAGE>

            (iii) a merger, consolidation or similar transaction following which
the Company is not the surviving corporation; or

            (iv)  a merger, consolidation or similar transaction following which
the Company is the surviving corporation but the shares of Common Stock
outstanding immediately preceding the merger, consolidation or similar
transaction are converted or exchanged by virtue of the merger, consolidation or
similar transaction into other property, whether in the form of securities, cash
or otherwise.

      (n)   "DIRECTOR" means a member of the Board of Directors of the Company.

      (o)   "DISABILITY" means the permanent and total disability of a person
within the meaning of Section 22(e)(3) of the Code.

      (p)   "EMPLOYEE" means any person employed by the Company or an Affiliate.
However, service solely as a Director, or payment of a fee for such services,
shall not cause a Director to be considered an "Employee" for purposes of the
Plan.

      (q)   "ENTITY" means a corporation, partnership or other entity.

      (r)   "EXCHANGE ACT" means the Securities Exchange Act of 1934, as
amended.

      (s)   "EXCHANGE ACT PERSON" means any natural person, Entity or "group"
(within the meaning of Section 13(d) or 14(d) of the Exchange Act), except that
"Exchange Act Person" shall not include (i) the Company or any Subsidiary of the
Company, (ii) any employee benefit plan of the Company or any Subsidiary of the
Company or any trustee or other fiduciary holding securities under an employee
benefit plan of the Company or any Subsidiary of the Company, (iii) an
underwriter temporarily holding securities pursuant to an offering of such
securities, (iv) an Entity Owned, directly or indirectly, by the stockholders of
the Company in substantially the same proportions as their Ownership of stock of
the Company; or (v) any natural person, Entity or "group" (within the meaning of
Section 13(d) or 14(d) of the Exchange Act) that, as of the effective date of
the Plan as set forth in Section 14, is the Owner, directly or indirectly, of
securities of the Company representing more than fifty percent (50%) of the
combined voting power of the Company's then outstanding securities.

      (t)   "FAIR MARKET VALUE" means, as of any date, the value of the Common
Stock determined as follows:

            (i)   If the Common Stock is listed on any established stock
exchange or traded on the Nasdaq National Market or the Nasdaq SmallCap Market,
the Fair Market Value of a share of Common Stock shall be the closing sales
price for such stock (or the closing bid, if no sales were reported) as quoted
on such exchange or market (or the exchange or market with the greatest volume
of trading in the Common Stock) on the last market trading day prior to the day
of determination, as reported in The Wall Street Journal or such other source as
the Board deems reliable.

            (ii)  In the absence of such markets for the Common Stock, the Fair
Market Value shall be determined by the Board in good faith.

                                       4.

<PAGE>

      (u)   "INITIAL GRANT" means an Option granted to a Non-Employee Director
who meets the specified criteria pursuant to Section 6(a).

      (v)   "IPO DATE" means the first day that the Common Stock is publicly
traded.

      (w)   "NON-EMPLOYEE DIRECTOR" means a Director who is not an Employee.

      (x)   "NONSTATUTORY STOCK OPTION" means an Option not intended to qualify
as an incentive stock option within the meaning of Section 422 of the Code and
the regulations promulgated thereunder.

      (y)   "OFFICER" means a person who is an officer of the Company within the
meaning of Section 16 of the Exchange Act and the rules and regulations
promulgated thereunder.

      (z)   "OPTION" means a Nonstatutory Stock Option granted pursuant to the
Plan.

      (aa)  "OPTION AGREEMENT" means a written agreement between the Company and
an Optionholder evidencing the terms and conditions of an individual Option
grant. Each Option Agreement shall be subject to the terms and conditions of the
Plan.

      (bb)  "OPTIONHOLDER" means a person to whom an Option is granted pursuant
to the Plan or, if applicable, such other person who holds an outstanding
Option.

      (cc)  "OWN," "OWNED," "OWNER," "OWNERSHIP" A person or Entity shall be
deemed to "Own," to have "Owned," to be the "Owner" of, or to have acquired
"Ownership" of securities if such person or Entity, directly or indirectly,
through any contract, arrangement, understanding, relationship or otherwise, has
or shares voting power, which includes the power to vote or to direct the
voting, with respect to such securities.

      (dd)  "PLAN" means this Volterra Semiconductor Corporation 2004
Non-Employee Directors' Stock Option Plan.

      (ee)  "RULE 16b-3" means Rule 16b-3 promulgated under the Exchange Act or
any successor to Rule 16b-3, as in effect from time to time.

      (ff)  "SECURITIES ACT" means the Securities Act of 1933, as amended.

      (gg)  "SUBSIDIARY" means, with respect to the Company, (i) any corporation
of which more than fifty percent (50%) of the outstanding capital stock having
ordinary voting power to elect a majority of the board of directors of such
corporation (irrespective of whether, at the time, stock of any other class or
classes of such corporation shall have or might have voting power by reason of
the happening of any contingency) is at the time, directly or indirectly, Owned
by the Company, and (ii) any partnership in which the Company has a direct or
indirect interest (whether in the form of voting or participation in profits or
capital contribution) of more than fifty percent (50%).

                                       5.

<PAGE>

3.    ADMINISTRATION.

      (a)   ADMINISTRATION BY BOARD. The Board shall administer the Plan. The
Board may not delegate administration of the Plan to a committee.

      (b)   POWERS OF BOARD. The Board shall have the power, subject to, and
within the limitations of, the express provisions of the Plan:

            (i)   To determine the provisions of each Option to the extent not
specified in the Plan.

            (ii)  To construe and interpret the Plan and Options granted under
it, and to establish, amend and revoke rules and regulations for its
administration. The Board, in the exercise of this power, may correct any
defect, omission or inconsistency in the Plan or in any Option Agreement, in a
manner and to the extent it shall deem necessary or expedient to make the Plan
fully effective.

            (iii) To amend the Plan or an Option as provided in Section 12.

            (iv)  Generally, to exercise such powers and to perform such acts as
the Board deems necessary or expedient to promote the best interests of the
Company and that are not in conflict with the provisions of the Plan.

      (c)   EFFECT OF BOARD'S DECISION. All determinations, interpretations and
constructions made by the Board in good faith shall not be subject to review by
any person and shall be final, binding and conclusive on all persons.

4.    SHARES SUBJECT TO THE PLAN.

      (a)   SHARE RESERVE. Subject to the provisions of Section 11 relating to
adjustments upon changes in the Common Stock, the Common Stock that may be
issued pursuant to Options shall not exceed in the aggregate two hundred fifty
thousand (250,000) shares of Common Stock, plus an annual increase for ten years
beginning on December 31, 2004 and ending on (and including) December 31, 2013
equal to the number of shares subject to Options granted during the calendar
year ending on such date. Notwithstanding the foregoing, the Board may act,
prior to the last day of any fiscal year of the Company, to increase the share
reserve by such number of shares of Common Stock as the Board shall determine,
which number shall be less than the amount described in the prior sentence.

      (b)   REVERSION OF SHARES TO THE SHARE RESERVE. If any Option shall for
any reason expire or otherwise terminate, in whole or in part, without having
been exercised in full, the shares of Common Stock not acquired under such
Option shall revert to and again become available for issuance under the Plan.

      (c)   SOURCE OF SHARES. The shares of Common Stock subject to the Plan may
be unissued shares or reacquired shares, bought on the market or otherwise.

                                       6.

<PAGE>

5.    ELIGIBILITY.

      The Options, as set forth in Section 6, automatically shall be granted
under the Plan to all Non-Employee Directors who meet the criteria specified in
Section 6.

6.    NON-DISCRETIONARY GRANTS.

      (a)   INITIAL GRANTS. Without any further action of the Board, each person
who after the IPO Date is elected or appointed for the first time to be a
Non-Employee Director automatically shall, upon the date of his or her initial
election or appointment to be a Non-Employee Director, be granted an Initial
Grant to purchase fifty thousand (50,000) shares of Common Stock on the terms
and conditions set forth herein.

      (b)   ANNUAL GRANTS. Without any further action of the Board, on the date
of each Annual Meeting, commencing with the Annual Meeting in 2005, each person
who is then a Non-Employee Director automatically shall be granted an Annual
Grant to purchase twelve thousand five hundred (12,500) shares of Common Stock
on the terms and conditions set forth herein; provided, however, that if the
person has not been serving as a Non-Employee Director for the entire period
since the preceding Annual Meeting, then the number of shares subject to such
Annual Grant shall be reduced pro rata for each full quarter prior to the date
of grant during which such person did not serve as a Non- Employee Director.

7.    OPTION PROVISIONS.

      Each Option shall be in such form and shall contain such terms and
conditions as required by the Plan. Each Option shall contain such additional
terms and conditions, not inconsistent with the Plan, as the Board shall deem
appropriate. Each Option shall include (through incorporation of provisions
hereof by reference in the Option or otherwise) the substance of each of the
following provisions:

      (a)   TERM. No Option shall be exercisable after the expiration of ten
(10) years from the date it was granted.

      (b)   EXERCISE PRICE. The exercise price of each Option shall be one
hundred percent (100%) of the Fair Market Value of the stock subject to the
Option on the date the Option is granted.

      (c)   CONSIDERATION. The purchase price of stock acquired pursuant to an
Option may be paid, to the extent permitted by applicable law, in any
combination of (i) cash or check, (ii) delivery to the Company of other Common
Stock or (iii) pursuant to a program developed under Regulation T as promulgated
by the Federal Reserve Board that, prior to the issuance of Common Stock,
results in either the receipt of cash (or check) by the Company or the receipt
of irrevocable instructions to pay the aggregate exercise price to the Company
from the sales proceeds. The purchase price of Common Stock acquired pursuant to
an Option that is paid by delivery to the Company of other Common Stock
acquired, directly or indirectly from the Company, shall be paid only by shares
of the Common Stock of the Company that have been held for more than six (6)
months (or such longer or shorter period of time required to avoid a charge to
earnings for financial accounting purposes).

                                       7.

<PAGE>

      (d)   TRANSFERABILITY. Except as otherwise provided for in this Section,
an Option is transferable only by will or by the laws of descent and
distribution and exercisable only by the Optionholder during the life of the
Optionholder. However, an Option may be transferred for no consideration upon
written consent of the Board if (i) at the time of transfer, a Form S-8
registration statement under the Securities Act is available for the issuance of
shares by the Company upon the exercise of such transferred Option or (ii) the
transfer is to the Optionholder's employer at the time of transfer or an
affiliate of the Optionholder's employer at the time of transfer. Any such
transfer is subject to such limits as the Board may establish, and subject to
the transferee agreeing to remain subject to all the terms and conditions
applicable to the Option prior to such transfer. The forgoing right to transfer
the Option shall apply to the right to consent to amendments to the Stock Option
Agreement for such Option. In addition, until the Optionholder transfers the
Option, an Optionholder may, by delivering written notice to the Company, in a
form provided by or otherwise satisfactory to the Company, designate a third
party who, in the event of the death of the Optionholder, shall thereafter be
entitled to exercise the Option.

      (e)   VESTING. Options shall vest as follows:

            (i)   Initial Grants: 1/4th of the shares shall vest one year after
the date of grant and 1/16th of the shares shall vest quarterly thereafter over
three (3) years.

            (ii)  Annual Grants: 1/4th of the shares shall vest one year after
the date of grant and 1/16th of the shares shall vest quarterly thereafter over
three (3) years.

      (f)   EARLY EXERCISE. The Option may, but need not, include a provision
whereby the Optionholder may elect at any time before the Optionholder's
Continuous Service terminates to exercise the Option as to any part or all of
the shares of Common Stock subject to the Option prior to the full vesting of
the Option. Any unvested shared of Common Stock so purchased may be subject to a
repurchase option in favor of the Company or to any other restriction the Board
determines to be appropriate. The Company will not exercise its repurchase
option until at least six (6) months (or such longer or shorter period of time
required to avoid a charge to earnings for financial accounting purposes) have
elapsed following exercise of the Option unless the Board otherwise specifically
provides in the Option.

      (g)   TERMINATION OF CONTINUOUS SERVICE. In the event that an
Optionholder's Continuous Service terminates (other than upon the Optionholder's
death or Disability or upon a Change in Control), the Optionholder may exercise
his or her Option (to the extent that the Optionholder was entitled to exercise
such Option as of the date of termination of Continuous Service) but only within
such period of time ending on the earlier of (i) the expiration of the term of
the Option as set forth in the Option Agreement or (ii) the date three (3)
months following the termination of the Optionholder's Continuous Service (or
such longer or shorter period specified in the Option Agreement). If, after
termination of Continuous Service, the Optionholder does not exercise his or her
Option within the time specified herein or in the Option Agreement (as
applicable), the Option shall terminate.

(h) EXTENSION OF TERMINATION DATE. If the exercise of the Option following the
termination of the Optionholder's Continuous Service (other than upon the
Optionholder's death

                                       8.

<PAGE>

or Disability) would be prohibited at any time solely because the issuance of
shares would violate the registration requirements under the Securities Act,
then the Option shall terminate on the earlier of (i) the expiration of the term
of the Option as set forth in the Option Agreement or (ii) the expiration of a
period of three (3) months after the termination of the Optionholder's
Continuous Service during which the exercise of the Option would not be in
violation of such registration requirements.

      (i)   DISABILITY OF OPTIONHOLDER. In the event an Optionholder's
Continuous Service terminates as a result of the Optionholder's Disability, the
Optionholder may exercise his or her Option (to the extent that the Optionholder
was entitled to exercise it as of the date of termination), but only within such
period of time ending on the earlier of (i) the date twelve (12) months
following such termination or (ii) the expiration of the term of the Option as
set forth in the Option Agreement. If, after termination, the Optionholder does
not exercise his or her Option within the time specified herein, the Option
shall terminate.

      (j)   DEATH OF OPTIONHOLDER. In the event (i) an Optionholder's Continuous
Service terminates as a result of the Optionholder's death or (ii) the
Optionholder dies within the three-month period after the termination of the
Optionholder's Continuous Service for a reason other than death, then the Option
may be exercised (to the extent the Optionholder was entitled to exercise the
Option as of the date of death) by the Optionholder's estate, by a person who
acquired the right to exercise the Option by bequest or inheritance or by a
person designated to exercise the Option upon the Optionholder's death, but only
within the period ending on the earlier of (1) the date eighteen (18) months
following the date of death or (2) the expiration of the term of such Option as
set forth in the Option Agreement. If, after death, the Option is not exercised
within the time specified herein, the Option shall terminate.

      (k)   TERMINATION UPON CHANGE IN CONTROL. In the event that an
Optionholder's Continuous Service terminates as of, or within twelve (12) months
following a Change in Control, the Optionholder may exercise his or her Option
(to the extent that the Optionholder was entitled to exercise such Option as of
the date of termination of Continuous Service) within such period of time ending
on the earlier of (i) the expiration of the term of the Option as set forth in
the Option Agreement or (ii) the date twelve (12) months following the
termination of the Optionholder's Continuous Service (or such longer or shorter
period specified in the Option Agreement). If, after termination of Continuous
Service, the Optionholder does not exercise his or her Option within the time
specified herein or in the Option Agreement (as applicable), the Option shall
terminate.

8.    SECURITIES LAW COMPLIANCE.

      The Company shall seek to obtain from each regulatory commission or agency
having jurisdiction over the Plan such authority as may be required to grant
Options and to issue and sell shares of Common Stock upon exercise of the
Options; provided, however, that this undertaking shall not require the Company
to register under the Securities Act the Plan, any Option or any stock issued or
issuable pursuant to any such Option. If, after reasonable efforts, the Company
is unable to obtain from any such regulatory commission or agency the authority
which counsel for the Company deems necessary for the lawful issuance and sale
of stock under the Plan, the

                                       9.

<PAGE>

Company shall be relieved from any liability for failure to issue and sell stock
upon exercise of such Options unless and until such authority is obtained.

9.    USE OF PROCEEDS FROM STOCK.

      Proceeds from the sale of stock pursuant to Options shall constitute
general funds of the Company.

10.   MISCELLANEOUS.

      (a)   STOCKHOLDER RIGHTS. No Optionholder shall be deemed to be the holder
of, or to have any of the rights of a holder with respect to, any shares subject
to such Option unless and until such Optionholder has satisfied all requirements
for exercise of the Option pursuant to its terms.

      (b)   NO SERVICE RIGHTS. Nothing in the Plan or any instrument executed or
Option granted pursuant thereto shall confer upon any Optionholder any right to
continue to serve the Company as a Non-Employee Director or shall affect the
right of the Company or an Affiliate to terminate (i) the employment of an
Employee with or without notice and with or without cause, (ii) the service of a
Consultant pursuant to the terms of such Consultant's agreement with the Company
or an Affiliate or (iii) the service of a Director pursuant to the Bylaws of the
Company or an Affiliate, and any applicable provisions of the corporate law of
the state in which the Company or the Affiliate is incorporated, as the case may
be.

      (c)   INVESTMENT ASSURANCES. The Company may require an Optionholder, as a
condition of exercising or acquiring stock under any Option, (i) to give written
assurances satisfactory to the Company as to the Optionholder's knowledge and
experience in financial and business matters and/or to employ a purchaser
representative reasonably satisfactory to the Company who is knowledgeable and
experienced in financial and business matters and that he or she is capable of
evaluating, alone or together with the purchaser representative, the merits and
risks of exercising the Option; and (ii) to give written assurances satisfactory
to the Company stating that the Optionholder is acquiring the stock subject to
the Option for the Optionholder's own account and not with any present intention
of selling or otherwise distributing the stock. The foregoing requirements, and
any assurances given pursuant to such requirements, shall be inoperative if (1)
the issuance of the shares upon the exercise or acquisition of stock under the
Option has been registered under a then currently effective registration
statement under the Securities Act or (2) as to any particular requirement, a
determination is made by counsel for the Company that such requirement need not
be met in the circumstances under the then applicable securities laws. The
Company may, upon advice of counsel to the Company, place legends on stock
certificates issued under the Plan as such counsel deems necessary or
appropriate in order to comply with applicable securities laws, including, but
not limited to, legends restricting the transfer of the stock.

      (d)   WITHHOLDING OBLIGATIONS. The Optionholder may satisfy any federal,
state or local tax withholding obligation relating to the exercise or
acquisition of stock under an Option by any of the following means (in addition
to the Company's right to withhold from any compensation paid to the
Optionholder by the Company) or by a combination of such means: (i)

                                      10.

<PAGE>

tendering a cash payment; (ii) authorizing the Company to withhold shares from
the shares of the Common Stock otherwise issuable to the Optionholder as a
result of the exercise or acquisition of stock under the Option; provided,
however, that no shares of Common Stock are withheld with a value exceeding the
minimum amount of tax required to be withheld by law; or (iii) delivering to the
Company owned and unencumbered shares of the Common Stock.

      (e)   ELECTRONIC DELIVERY. Any reference herein to a "written" agreement
or document shall include any agreement or document delivered electronically or
posted on the Company's intranet.

11.   ADJUSTMENTS UPON CHANGES IN COMMON STOCK.

      (a)   CAPITALIZATION ADJUSTMENTS. If any change is made in, or other
events occur with respect to, the stock subject to the Plan, or subject to any
Option, without the receipt of consideration by the Company (through merger,
consolidation, reorganization, recapitalization, reincorporation, stock
dividend, dividend in property other than cash, stock split, liquidating
dividend, combination of shares, exchange of shares, change in corporate
structure or other transaction not involving the receipt of consideration by the
Company (each a "Capitalization Adjustment")), the Plan will be appropriately
adjusted in the class(es) and maximum number of securities subject both to the
Plan pursuant to Section 4 and to the nondiscretionary Options specified in
Section 6, and the outstanding Options will be appropriately adjusted in the
class(es) and number of securities and price per share of stock subject to such
outstanding Options. The Board shall make such adjustments, and its
determination shall be final, binding and conclusive. (The conversion of any
convertible securities of the Company shall not be treated as a transaction
"without receipt of consideration" by the Company.)

      (b)   DISSOLUTION OR LIQUIDATION. In the event of a dissolution or
liquidation of the Company, then all outstanding Options shall terminate
immediately prior to the completion of such dissolution or liquidation.

      (c)   CORPORATE TRANSACTION. In the event of a Corporate Transaction, any
surviving corporation or acquiring corporation (or the surviving or acquiring
corporation's parent company) may assume or continue any or all Options
outstanding under the Plan or may substitute similar stock options for Options
outstanding under the Plan (it being understood that similar stock options
include, but are not limited to, options to acquire the same consideration paid
to the stockholders or the Company, as the case may be, pursuant to the
Corporate Transaction). In the event that any surviving corporation or acquiring
corporation (or its parent company) does not assume or continue all such
outstanding Options or substitute similar stock options for such outstanding
Options, then with respect to Options that have been not assumed, continued or
substituted and are held by Optionholders whose Continuous Service has not
terminated prior to the effective time of the Corporate Transaction, the vesting
of such Options (and, if applicable, the time at which such Options may be
exercised) shall (contingent upon the effectiveness of the Corporate
Transaction) be accelerated in full to a date prior to the effective time of
such Corporate Transaction as the Board shall determine (or, if the Board shall
not determine such a date, to the date that is five (5) days prior to the
effective time of the Corporate Transaction), and the Options shall terminate if
not exercised (if applicable) at or prior to such effective time. With respect
to any other Options outstanding under the Plan that have not been

                                      11.

<PAGE>

assumed, continued or substituted, the vesting of such Options (and, if
applicable, the time at which such Options may be exercised) shall not be
accelerated unless otherwise provided in Section 11(d) or in a written agreement
between the Company or any Affiliate and the holder of such Options, and such
Options shall terminate if not exercised (if applicable) prior to the effective
time of the Corporate Transaction.

      (d)   CHANGE IN CONTROL. If a Change in Control occurs and an
Optionholder's Continuous Service with the Company has not terminated
immediately prior to the effective time of the Change in Control, then,
immediately prior to the effective time of such Change in Control (and
contingent upon the effectiveness of the Change in Control), the vesting and
exercisability of an Optionholder's Options shall be accelerated in full. In the
event that an Optionholder is required to resign his or her position as a
Non-Employee Director as a condition of a Change in Control, the outstanding
Options of such Optionholder shall become fully vested and exercisable
immediately prior to the effectiveness of such resignation (and contingent upon
the effectiveness of the Change in Control).

      (e)   PARACHUTE PAYMENTS. If the acceleration of the vesting and
exercisability of Options provided for in Section 11(c), together with payments
and other benefits of an Optionholder, (collectively, the "Payment") (i)
constitute a "parachute payment" within the meaning of Section 280G of the Code,
or any comparable successor provisions, and (ii) but for this Section 11(e)
would be subject to the excise tax imposed by Section 4999 of the Code, or any
comparable successor provisions (the "Excise Tax"), then such Payment shall be
either (1) provided to such Optionholder in full, or (2) provided to such
Optionholder as to such lesser extent that would result in no portion of such
Payment being subject to the Excise Tax, whichever of the foregoing amounts,
when taking into account applicable federal, state, local and foreign income and
employment taxes, the Excise Tax, and any other applicable taxes, results in the
receipt by such Optionholder, on an after-tax basis, of the greatest amount of
the Payment, notwithstanding that all or some portion of the Payment may be
subject to the Excise Tax.

            Unless the Company and such Optionholder otherwise agree in writing,
any determination required under this Section 11(e) shall be made in writing in
good faith by the Accountant. If a reduction in the Payment is to be made as
provided above, reductions shall occur in the following order unless the
Optionholder elects in writing a different order (provided, however, that such
election shall be subject to Company approval if made on or after the date that
triggers the Payment or a portion thereof): reduction of cash payments;
cancellation of accelerated vesting of Options; reduction of employee benefits.
If acceleration of vesting of Options is to be reduced, such acceleration of
vesting shall be cancelled in the reverse order of date of grant of Options
(i.e., earliest granted Option cancelled last) unless the Optionholder elects in
writing a different order for cancellation.

            For purposes of making the calculations required by this Section
11(e), the Accountant may make reasonable assumptions and approximations
concerning applicable taxes and may rely on reasonable, good faith
interpretations concerning the application of the Code and other applicable
legal authority. The Company and the Optionholder shall furnish to the
Accountant such information and documents as the Accountant may reasonably
request in order to make such a determination. The Company shall bear all costs
the Accountant may reasonably incur in connection with any calculations
contemplated by this Section 11(e).

                                      12.

<PAGE>

            If, notwithstanding any reduction described above, the Internal
Revenue Service (the "IRS") determines that the Optionholder is liable for the
Excise Tax as a result of the Payment, then the Optionholder shall be obligated
to pay back to the Company, within thirty (30) days after a final IRS
determination or, in the event that the Optionholder challenges the final IRS
determination, a final judicial determination, a portion of the Payment equal to
the "Repayment Amount." The Repayment Amount with respect to the Payment shall
be the smallest such amount, if any, as shall be required to be paid to the
Company so that the Optionholder's net after-tax proceeds with respect to the
Payment (after taking into account the payment of the Excise Tax and all other
applicable taxes imposed on the Payment) shall be maximized. The Repayment
Amount with respect to the Payment shall be zero if a Repayment Amount of more
than zero would not result in the Optionholder's net after-tax proceeds with
respect to the Payment being maximized. If the Excise Tax is not eliminated
pursuant to this paragraph, the Optionholder shall pay the Excise Tax.

            Notwithstanding any other provision of this Section 11(e), if (i)
there is a reduction in the Payment as described above, (ii) the IRS later
determines that the Optionholder is liable for the Excise Tax, the payment of
which would result in the maximization of the Optionholder's net after-tax
proceeds of the Payment (calculated as if the Payment had not previously been
reduced), and (iii) the Optionholder pays the Excise Tax, then the Company shall
pay or otherwise provide to the Optionholder that portion of the Payment that
was reduced pursuant to this Section 11(e) contemporaneously or as soon as
administratively possible after the Optionholder pays the Excise Tax so that the
Optionholder's net after-tax proceeds with respect to the Payment are maximized.

            If the Optionholder either (i) brings any action to enforce rights
pursuant to this Section 11(e), or (ii) defends any legal challenge to his or
her rights under this Section 11(e), the Optionholder shall be entitled to
recover attorneys' fees and costs incurred in connection with such action,
regardless of the outcome of such action; provided, however, that if such action
is commenced by the Optionholder, the court finds that the action was brought in
good faith.

12.   AMENDMENT OF THE PLAN AND OPTIONS.

      (a)   AMENDMENT OF PLAN. The Board, at any time and from time to time, may
amend the Plan. However, except as provided in Section 11 relating to
adjustments upon changes in Common Stock, no amendment shall be effective unless
approved by the stockholders of the Company to the extent stockholder approval
is necessary to satisfy the requirements of applicable laws.

      (b)   STOCKHOLDER APPROVAL. The Board, in its sole discretion, may submit
any other amendment to the Plan for stockholder approval.

      (c)   NO IMPAIRMENT OF RIGHTS. Rights under any Option granted before
amendment of the Plan shall not be impaired by any amendment of the Plan unless
(i) the Company requests the consent of the Optionholder and (ii) the
Optionholder consents in writing.

      (d)   AMENDMENT OF OPTIONS. The Board, at any time, and from time to time,
may amend the terms of any one or more Options; provided, however, that the
rights under any

                                      13.

<PAGE>

Option shall not be impaired by any such amendment unless (i) the Company
requests the consent of the Optionholder and (ii) the Optionholder consents in
writing.

13.   TERMINATION OR SUSPENSION OF THE PLAN.

      (a)   PLAN TERM. The Board may suspend or terminate the Plan at any time.
No Options may be granted under the Plan while the Plan is suspended or after it
is terminated.

      (b)   NO IMPAIRMENT OF RIGHTS. Suspension or termination of the Plan shall
not impair rights and obligations under any Option granted while the Plan is in
effect except with the written consent of the Optionholder.

14.   EFFECTIVE DATE OF PLAN.

      The Plan shall become effective on the IPO Date, but no Option shall be
exercised unless and until the Plan has been approved by the stockholders of the
Company, which approval shall be within twelve (12) months before or after the
date the Plan is adopted by the Board.

15.   CHOICE OF LAW.

      The law of the state of Delaware shall govern all questions concerning the
construction, validity and interpretation of this Plan, without regard to such
state's conflict of laws rules.

                                      14.

<PAGE>

                       VOLTERRA SEMICONDUCTOR CORPORATION
                 2004 NON-EMPLOYEE DIRECTORS' STOCK OPTION PLAN

                            STOCK OPTION GRANT NOTICE
                           ([INITIAL] [ANNUAL] GRANT)

Volterra Semiconductor Corporation (the "Company"), pursuant to its 2004
Non-Employee Directors' Stock Option Plan (the "Plan"), hereby grants to
Optionholder an option to purchase the number of shares of the Company's Common
Stock set forth below. This option is subject to all of the terms and conditions
as set forth herein and in the Stock Option Agreement, the Plan and the Notice
of Exercise, all of which are attached hereto and incorporated herein in their
entirety.

   Optionholder:                        __________________________________
   Date of Grant:                       __________________________________
   Vesting Commencement Date:           __________________________________
   Number of Shares Subject to Option:  __________________________________
   Exercise Price (Per Share):          __________________________________
   Total Exercise Price:                __________________________________
   Expiration Date:                     __________________________________

TYPE OF GRANT:      Nonstatutory Stock Option

EXERCISE SCHEDULE:  [X] Same as Vesting Schedule     [ ] Early Exercise
                                                         Permitted

VESTING SCHEDULE:   1/4th of the shares vest one year after the Vesting
                    Commencement Date.

                    1/16th of the shares vest quarterly thereafter over the next
                    three years.

PAYMENT:            By one or a combination of the following items (described
                    in the Stock Option Agreement):

                    [ ]  By cash or check
                    [ ]  Pursuant to a Regulation T Program if the Shares are
                         publicly traded
                    [ ]  By delivery of already-owned shares if the Shares are
                         publicly traded

ADDITIONAL TERMS/ACKNOWLEDGEMENTS: The undersigned Optionholder acknowledges
receipt of, and understands and agrees to, this Stock Option Grant Notice, the
Stock Option Agreement and the Plan. Optionholder further acknowledges that as
of the Date of Grant, this Stock Option Grant Notice, the Stock Option Agreement
and the Plan set forth the entire understanding between Optionholder and the
Company regarding the acquisition of stock in the Company and supersede all
prior oral and written agreements on that subject with the exception of (i)
options previously granted and delivered to Optionholder under the Plan, and
(ii) the following agreements only:

         OTHER AGREEMENTS:
                                            ____________________________________
                                            ____________________________________

VOLTERRA SEMICONDUCTOR CORPORATION          OPTIONHOLDER:

By: ________________________________        ____________________________________
               Signature                                 Signature

Title: _____________________________        Date: ______________________________

Date:_______________________________

ATTACHMENTS: Stock Option Agreement, 2004 Non-Employee Directors' Stock Option
             Plan and Notice of Exercise

<PAGE>

                                  ATTACHMENT I

                             STOCK OPTION AGREEMENT

<PAGE>

                                  ATTACHMENT II

                 2004 NON-EMPLOYEE DIRECTORS' STOCK OPTION PLAN

<PAGE>

                                 ATTACHMENT III

                               NOTICE OF EXERCISE

<PAGE>

                       VOLTERRA SEMICONDUCTOR CORPORATION
                 2004 NON-EMPLOYEE DIRECTORS' STOCK OPTION PLAN

                             STOCK OPTION AGREEMENT
                           (NONSTATUTORY STOCK OPTION)

      Pursuant to your Stock Option Grant Notice ("Grant Notice") and this Stock
Option Agreement, Volterra Semiconductor Corporation (the "Company") has granted
you an option under its 2004 Non-Employee Directors' Stock Option Plan (the
"Plan") to purchase the number of shares of the Company's Common Stock indicated
in your Grant Notice at the exercise price indicated in your Grant Notice.
Defined terms not explicitly defined in this Stock Option Agreement but defined
in the Plan shall have the same definitions as in the Plan.

      The details of your option are as follows:

      1.    VESTING. Subject to the limitations contained herein, your option
will vest as provided in your Grant Notice, provided that vesting will cease
upon the termination of your Continuous Service.

      2.    NUMBER OF SHARES AND EXERCISE PRICE. The number of shares of Common
Stock subject to your option and your exercise price per share referenced in
your Grant Notice may be adjusted from time to time for Capitalization
Adjustments.

      3.    EXERCISE PRIOR TO VESTING ("EARLY EXERCISE"). If permitted in your
Grant Notice (i.e., the "Exercise Schedule" indicates that "Early Exercise" of
your option is permitted) and subject to the provisions of your option, you may
elect at any time that is both (i) during the period of your Continuous Service
and (ii) during the term of your option, to exercise all or part of your option,
including the nonvested portion of your option; provided, however, that:

            (a)   a partial exercise of your option shall be deemed to cover
first vested shares of Common Stock and then the earliest vesting installment of
unvested shares of Common Stock;

            (b)   any shares of Common Stock so purchased from installments that
have not vested as of the date of exercise shall be subject to the purchase
option in favor of the Company as described in the Company's form of Early
Exercise Stock Purchase Agreement; and

            (c)   you shall enter into the Company's form of Early Exercise
Stock Purchase Agreement with a vesting schedule that will result in the same
vesting as if no early exercise had occurred.

      4.    METHOD OF PAYMENT. Payment of the exercise price is due in full upon
exercise of all or any part of your option. You may elect to make payment of the
exercise price in cash or by check or in any other manner PERMITTED BY YOUR
GRANT NOTICE, which may include one or more of the following:

                                      1.

<PAGE>

                  (a)   In the Company's sole discretion at the time your option
is exercised and provided that at the time of exercise the Common Stock is
publicly traded and quoted regularly in The Wall Street Journal, pursuant to a
program developed under Regulation T as promulgated by the Federal Reserve Board
that, prior to the issuance of Common Stock, results in either the receipt of
cash (or check) by the Company or the receipt of irrevocable instructions to pay
the aggregate exercise price to the Company from the sales proceeds.

                  (b)   Provided that at the time of exercise the Common Stock
is publicly traded and quoted regularly in The Wall Street Journal, by delivery
of already-owned shares of Common Stock either that you have held for the period
required to avoid a charge to the Company's reported earnings (generally six (6)
months) or that you did not acquire, directly or indirectly from the Company,
that are owned free and clear of any liens, claims, encumbrances or security
interests, and that are valued at Fair Market Value on the date of exercise.
"Delivery" for these purposes, in the sole discretion of the Company at the time
you exercise your option, shall include delivery to the Company of your
attestation of ownership of such shares of Common Stock in a form approved by
the Company. Notwithstanding the foregoing, you may not exercise your option by
tender to the Company of Common Stock to the extent such tender would violate
the provisions of any law, regulation or agreement restricting the redemption of
the Company's stock.

      5.    WHOLE SHARES. You may exercise your option only for whole shares of
Common Stock.

      6.    SECURITIES LAW COMPLIANCE. Notwithstanding anything to the contrary
contained herein, you may not exercise your option unless the shares of Common
Stock issuable upon such exercise are then registered under the Securities Act
or, if such shares of Common Stock are not then so registered, the Company has
determined that such exercise and issuance would be exempt from the registration
requirements of the Securities Act. The exercise of your option also must comply
with other applicable laws and regulations governing your option, and you may
not exercise your option if the Company determines that such exercise would not
be in material compliance with such laws and regulations.

      7.    TERM. You may not exercise your option before the commencement or
after the expiration of its term. The term of your option commences on the Date
of Grant and expires upon the earliest of the following:

            (a)   three (3) months after the termination of your Continuous
Service for any reason other than your Disability or death or upon a Change in
Control, provided that if during any part of such three (3) month period your
option is not exercisable solely because of the condition set forth in Section
6, your option shall not expire until the earlier of the Expiration Date or
until it shall have been exercisable for an aggregate period of three (3) months
after the termination of your Continuous Service;

            (b)   twelve (12) months after the termination of your Continuous
Service due to your Disability;

                                       2.

<PAGE>

            (c)   eighteen (18) months after your death if you die either during
your Continuous Service or within three (3) months after your Continuous Service
terminates;

            (d)   twelve (12) months after the termination of your Continuous
Service if such termination occurs as of, or within thirteen (13) months
[FOLLOWING] [OF], the effective time of such Change in Control;

            (e)   the Expiration Date indicated in your Grant Notice; or

            (f)   the day before the tenth (10th) anniversary of the Date of
Grant.

      8.    EXERCISE.

            (a)   You may exercise the vested portion of your option (and the
unvested portion of your option if your Grant Notice so permits) during its term
by delivering a Notice of Exercise (in a form designated by the Company)
together with the exercise price to the Secretary of the Company, or to such
other person as the Company may designate, during regular business hours,
together with such additional documents as the Company may then require.

            (b)   By exercising your option you agree that, as a condition to
any exercise of your option, the Company may require you to enter into an
arrangement providing for the payment by you to the Company of any tax
withholding obligation of the Company arising by reason of (1) the exercise of
your option, (2) the lapse of any substantial risk of forfeiture to which the
shares of Common Stock are subject at the time of exercise, or (3) the
disposition of shares of Common Stock acquired upon such exercise.

      9.    TRANSFERABILITY. Your option is transferable only by will or by the
laws of descent and distribution and is exercisable only by you during your
lifetime. However, you may transfer your option for no consideration upon
written consent of the Board (i) if, at the time of transfer, a Form S-8
registration statement under the Securities Act is available for the issuance of
shares by the Company upon the exercise of such transferred option or (ii) the
transfer is to your employer at the time of transfer or an affiliate of your
employer at the time of transfer. Any such transfer is subject to such limits as
the Board may establish, and subject to the transferee agreeing to remain
subject to all the terms and conditions applicable to your option prior to such
transfer. The forgoing right to transfer your option shall apply to the right to
consent to amendments to the Stock Option Agreement for such option. In
addition, until you transfers the option, you may, by delivering written notice
to the Company, in a form provided by or otherwise satisfactory to the Company,
designate a third party who, in the event of your death, shall thereafter be
entitled to exercise your option.

      10.   OPTION NOT A SERVICE CONTRACT. Your option is not an employment or
service contract, and nothing in your option shall be deemed to create in any
way whatsoever any obligation on your part to continue in the employ of the
Company or an Affiliate, or of the Company or an Affiliate to continue your
employment. In addition, nothing in your option shall obligate the Company or an
Affiliate, their respective stockholders, Boards of Directors, Officers or
Employees to continue any relationship that you might have as a Director or
Consultant for the Company or an Affiliate.

                                       3.

<PAGE>

      11.   WITHHOLDING OBLIGATIONS.

            (a)   At the time you exercise your option, in whole or in part, or
at any time thereafter as requested by the Company, you hereby authorize
withholding from payroll and any other amounts payable to you, and otherwise
agree to make adequate provision for (including by means of a "cashless
exercise" pursuant to a program developed under Regulation T as promulgated by
the Federal Reserve Board to the extent permitted by the Company), any sums
required to satisfy the federal, state, local and foreign tax withholding
obligations of the Company or an Affiliate, if any, which arise in connection
with the exercise of your option.

            (b)   Upon your request and subject to approval by the Company, in
its sole discretion, and compliance with any applicable legal conditions or
restrictions, the Company may withhold from fully vested shares of Common Stock
otherwise issuable to you upon the exercise of your option a number of whole
shares of Common Stock having a Fair Market Value, determined by the Company as
of the date of exercise, not in excess of the minimum amount of tax required to
be withheld by law (or such lower amount as may be necessary to avoid variable
award accounting). If the date of determination of any tax withholding
obligation is deferred to a date later than the date of exercise of your option,
share withholding pursuant to the preceding sentence shall not be permitted
unless you make a proper and timely election under Section 83(b) of the Code,
covering the aggregate number of shares of Common Stock acquired upon such
exercise with respect to which such determination is otherwise deferred, to
accelerate the determination of such tax withholding obligation to the date of
exercise of your option. Notwithstanding the filing of such election, shares of
Common Stock shall be withheld solely from fully vested shares of Common Stock
determined as of the date of exercise of your option that are otherwise issuable
to you upon such exercise. Any adverse consequences to you arising in connection
with such share withholding procedure shall be your sole responsibility.

            (c)   You may not exercise your option unless the tax withholding
obligations of the Company and/or any Affiliate are satisfied. Accordingly, you
may not be able to exercise your option when desired even though your option is
vested, and the Company shall have no obligation to issue a certificate for such
shares of Common Stock or release such shares of Common Stock from any escrow
provided for herein unless such obligations are satisfied.

      12.   NOTICES. Any notices provided for in your option or the Plan shall
be given in writing and shall be deemed effectively given upon receipt or, in
the case of notices delivered by mail by the Company to you, five (5) days after
deposit in the United States mail, postage prepaid, addressed to you at the last
address you provided to the Company.

      13.   GOVERNING PLAN DOCUMENT. Your option is subject to all the
provisions of the Plan, the provisions of which are hereby made a part of your
option, and is further subject to all interpretations, amendments, rules and
regulations, which may from time to time be promulgated and adopted pursuant to
the Plan. In the event of any conflict between the provisions of your option and
those of the Plan, the provisions of the Plan shall control.

                                       4.

<PAGE>

                               NOTICE OF EXERCISE

Volterra Semiconductor Corporation
3839 Spinnaker Court
Fremont, CA 94538-6537                         Date of Exercise: _______________

Ladies and Gentlemen:

      This constitutes notice under my stock option that I elect to purchase the
number of shares for the price set forth below.

         Type of option:                             Nonstatutory

         Stock option dated:                         _______________

         Number of shares as
         to which option is
         exercised:                                  _______________

         Certificates to be
         issued in name of:                          _______________

         Total exercise price:                       $______________

         Cash payment delivered
         herewith:                                   $______________

         Value of ________ shares of
         Volterra Semiconductor Corporation Common
         Stock delivered herewith(1):                $______________

      By this exercise, I agree (i) to provide such additional documents as you
may require pursuant to the terms of the Volterra Semiconductor Corporation 2004
Non-Employee Directors' Stock Option Plan, and (ii) to provide for the payment
by me to you (in the manner designated by you) of your withholding obligation,
if any, relating to the exercise of this option.

--------------------------
(1) Shares must meet the public trading requirements set forth in the option.
Shares must be valued in accordance with the terms of the option being
exercised, must have been owned for the minimum period required in the option,
and must be owned free and clear of any liens, claims, encumbrances or security
interests. Certificates must be endorsed or accompanied by an executed
assignment separate from certificate.

                                       1.

<PAGE>

                                                Very truly yours,
                                                ________________________________



                                       2.