Exhibit 10.3

[Letterhead of C]

November 15, 2006

SunPower Corporation

3939 North First Street

San Jose, California 95134

Attn: Chief Financial Officer

Dear Mr. Hernandez:

SunPower Corporation (“Parent”), a Delaware corporation and a majority-owned
subsidiary of Cypress Semiconductor Corp. (“Cypress”), is today entering into an
Agreement and Plan of Merger (the “Merger Agreement”; capitalized terms used but
not otherwise defined herein have the meaning ascribed to them in the Merger
Agreement) among Parent, Pluto Acquisition Company LLC, a Delaware limited
liability company and a wholly-owned subsidiary of Parent, Pluto Corporation, a
California corporation (the “Company”), and Thomas L. Dinwoodie, as
Shareholders’ Representative, pursuant to which, among other things, the Company
is to be merged with and into Merger Sub (the “Merger”). A portion of the
consideration to be paid by Parent in connection with the Merger consists of
cash, and Parent desires to finance such cash consideration following the date
hereof. In order to facilitate such financing and the transactions contemplated
by the Merger Agreement, Cypress hereby agrees as set forth in this letter
agreement.

Upon the written request of Parent any time following the date hereof and prior
to the earlier of (i) the termination of the Merger Agreement in accordance with
its terms and (ii) the date six months following the Closing Date, Cypress shall
lend to Parent up to $130,000,000 in cash, as requested by Parent, on the
following terms:

 

  •   Title and Rank: Senior Subordinated Unsecured Note (the “Note”). The Note
shall rank junior and be subordinated to existing and future indebtedness of
Parent under Bank Credit Facilities.

 

  •   Security: None; the Note shall be unsecured.

 

  •   Interest Rate: LIBOR on the issuance date plus 475 basis points.

 

  •   Default Interest Rate: The otherwise applicable interest rate plus 200
basis points.

 

  •   Maturity and Payments: The Note shall mature on the first anniversary of
issuance date. Except as provided below in connection with an Equity Financing,
Bank Credit Facility or Debt Financing, no payments of principal or interest
shall be due until maturity.

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  •   Prepayment: The Note shall be prepayable at the option of Parent with no
penalty. Once repaid or prepaid, the loans may not be reborrowed.

 

  •   Mandatory Prepayment: The net proceeds (after deduction of direct and
indirect issuance costs) of any Bank Credit Facility, Equity Financing or Debt
Financing (each as defined below) by Parent shall be first applied on the same
business day as receipt thereof by Parent to reduce amounts outstanding under
the Note, with such proceeds being applied first to accrued and unpaid interest
and second to principal.

 

  •   Conditions Precedent to Borrowing. Parent may make requests for loans
under the Note on up to four occasions in increments of not less than
$30,000,000. The conditions precedent to a borrowing include delivery of notice,
accuracy of representations and warranties and absence of any material defaults.

 

  •   Affirmative Covenants. The Note shall include customary covenants
including with respect to delivery of financial statements and other
information, notices of defaults, litigation and other material events,
inspections, maintenance of property and insurance, maintenance of existence and
corporate franchises, payment of taxes, compliance with laws, ERISA and use of
proceeds.

 

  •   Negative Covenants. The Note shall include customary covenants including
with respect to limitations on the incurrence of debt, granting of liens,
fundamental changes, asset sales, investments and acquisitions, transactions
with affiliates, dividends or distributions on, or redemptions of, equity
interests.

 

  •   Representations and Warranties. Parent shall make customary
representations and warranties, including with respect to corporate status,
authority and enforceability, no violation of laws or agreements, litigation,
margin regulations, Investment Company Act, accuracy of disclosure, financial
statements and no material adverse change, taxes, ERISA, intellectual property
and environmental laws.

 

  •   Events of Default: Events of default for the Note shall include nonpayment
of principal and interest, violation of covenants, incorrectness of
representations and warranties in any respect, cross default and cross
acceleration with other indebtedness, material judgments, and bankruptcy-related
events.

For purposes of this letter:

 

  •   “Equity Financing” means the sale by Parent of its capital stock for cash,
but shall not include any sale by Parent of any capital stock or right to
acquire capital stock (i) pursuant to any stock option, stock purchase or other
equity incentive or benefit plan or other arrangement for compensation, in each
case for its employees, directors or consultants or (ii) to Cypress.

 

  •   “Debt Financing” means any sale of debt securities of Parent for cash,
other than (i) pursuant to or in connection with any Bank Credit Facility, or
(ii) to Cypress.

Commitment Letter

 

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  •   “Bank Credit Facility” means (a) one or more debt, credit or commercial
paper facilities, or lines of credit, in each case with banks or other
institutional lenders providing for revolving credit loans, term loans, lines of
credit or letters of credit, together with the documents related thereto
(including, without limitation, any guarantee agreements and security
documents), as the same may be amended, supplemented or otherwise modified from
time to time, including amendments, supplements or modifications relating to the
addition or elimination of Parent or any of its subsidiaries as borrowers,
guarantors or other credit parties thereunder and (b) any renewal, extension,
refunding, restructuring, replacement or refinancing thereof (whether with the
original lenders or agents or one or more other lenders and agents).

Each of Cypress and Parent shall use commercially reasonable efforts, and shall
cooperate with the other party, to take, or cause to be taken, all actions, and
to do, or cause to be done, all things necessary, appropriate or desirable to
consummate and make effective, in the most expeditious manner practicable
following the written request by Parent to Cypress described above, the loan and
the issuance of the Note contemplated hereby. Each of Cypress’s and Parent agree
to work in good faith toward the negotiation of commercially reasonable
definitive documentation for the loan. Without limiting the generality or effect
of the foregoing, each party, at the reasonable request of the other party,
shall execute and deliver such other instruments and agreements (including
definitive documentation for the loan and the Note and subordination agreements
requested by lenders of Parent) and do and perform such other acts and things as
may be necessary or reasonably desirable for effecting completely the loan and
the issuance of the Note contemplated hereby.

Commitment Letter

 

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This letter agreement shall be binding on the undersigned and the successors,
heirs, personal representatives and assigns of the undersigned, and shall
governed by, and construed in accordance with, the laws of the State of New
York.

 

Very truly yours, CYPRESS SEMICONDUCTOR CORP. By:  

/s/ Brad W. Buss

Name:   Brad W. Buss Title:   Executive Vice President, Finance and  
Administration, Chief Financial Officer

 

ACKNOWLEDGED AND AGREED As of November 15, 2006: SUNPOWER CORPORATION By:  

/s/ Emmanuel Hernandez

Name:   Emmanuel Hernandez Title:   Chief Financial Officer

Commitment Letter

 

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