Exhibit 5.1

[LATHAM & WATKINS LLP LETTERHEAD]

June 7, 2007

National Semiconductor Corporation
3689 Kifer Road
P.O. Box 58090
Mail Stop G3-135
Santa Clara, California 95052-8090

Re:

Registration Statement on Form S-3; Debt Securities of National Semiconductor Corporation

Ladies and Gentlemen:

        We have acted as special counsel to National Semiconductor Corporation, a Delaware corporation (the "Company"), in connection with their filing on June 7, 2007 with the Securities and Exchange Commission (the "Commission") under the Securities Act of 1933, as amended (the "Act"), of a registration statement on Form S-3 (the "Registration Statement"), pertaining to the registration of debt securities for sale from time to time. This opinion is being furnished in connection with the requirements of Item 601(b)(5) of Regulation S-K under the Act, and no opinion is expressed herein as to any matter pertaining to the contents of the Registration Statement, the Prospectus or any Prospectus Supplement (both as herein defined) other than as expressly stated herein with respect to the issue of the Debt Securities (as herein defined).

        You have provided us with a draft of the Registration Statement, in the form in which it will be filed, which includes a prospectus (the "Prospectus"). The Prospectus provides that it may be supplemented by one or more supplements to the Prospectus (each, a "Prospectus Supplement"). The Prospectus, as supplemented by various Prospectus Supplements, will provide for the registration by the Company of one or more series of debt securities, which may be either senior, senior subordinated or subordinated debt securities (the "Debt Securities"). The Debt Securities may be issued pursuant to an indenture by and between the Company and a financial institution to be identified therein as trustee (the "Trustee") in the form included as Exhibit 4.2 to the Registration Statement, as such indenture may be supplemented from time to time (the "Indenture").

        In our capacity as your special counsel in connection with the Registration Statement we are familiar with the proceedings taken and proposed to be taken by the Company in connection with the authorization of the Indenture and the authorization, issuance and sale of the Debt Securities. For purposes of this opinion, we have assumed that such proposed proceedings will be timely completed in the manner presently proposed and that the terms of each issuance will be in compliance with law. In addition, we have examined such matters of fact and questions of law as we have considered appropriate for purposes of this letter. With your consent, we have relied upon the foregoing and upon certificates and other assurances of officers of the Company and others as to factual matters without having independently verified such factual matters.

        We are opining herein as to the effect on the subject transaction only of the General Corporation Law of the State of Delaware and the internal laws of the State of New York, and we express no opinion with respect to the applicability thereto, or the effect thereon, of the laws of any other jurisdiction or, in the case of Delaware, any other laws, or as to any matters of municipal law or the laws of any local agencies within any state.

        Subject to the foregoing and the other matters set forth herein, it is our opinion that as of the date hereof:

        1.     When (i) the Indenture has been duly authorized, executed and delivered by the Company and the Trustee, (ii) the Debt Securities have been duly authorized and duly issued in accordance with the Indenture and applicable law (including, without limitation, by the adoption by the Board of Directors of the Company or an authorized committee thereof of a resolution duly authorizing the

issuance and delivery of the Debt Securities) (the "Debt Securities Authorization"), duly authenticated by the Trustee and duly executed and delivered on behalf of the Company against payment therefor in accordance with the terms and provisions of the Indenture and as contemplated by the Registration Statement, the Prospectus and the related Prospectus Supplement(s), and the Debt Securities Authorization, and (iii) the Registration Statement and any required post-effective amendments thereto have all become effective under the Securities Act and any and all Prospectus Supplement(s) required by applicable laws have been delivered and filed as required by such laws, and assuming that (a) the terms of the Debt Securities as executed and delivered are as described in the Registration Statement, the Prospectus and the related Prospectus Supplement(s), and the Debt Securities Authorization, (b) the Debt Securities as executed and delivered do not violate any law applicable to the Company or result in a default under or breach of any agreement or instrument binding upon the Company, (c) the Debt Securities as executed and delivered comply with all requirements and restrictions, applicable to the Company, whether imposed by any court or governmental or regulatory body having jurisdiction over the Company or otherwise, and (d) the Debt Securities are then issued and sold as contemplated in the Registration Statement, the Prospectus and the related Prospectus Supplement(s), and the Debt Securities Authorization, the Debt Securities will constitute legally valid and binding obligations of the Company, enforceable against the Company in accordance with their terms.

        2.     When (i) the Indenture has been duly authorized, executed and delivered by the Company and the Trustee, (ii) the Registration Statement and any required post-effective amendments thereto have all become effective under the Securities Act and any and all Prospectus Supplement(s) required by applicable laws have been delivered and filed as required by such laws, and assuming that (a) the Indenture does not violate any law applicable to the Company or result in a default under or breach of any agreement or instrument binding upon the Company, and (b) the Indenture complies with all requirements and restrictions, if any, applicable to the Company, whether imposed by any court or governmental or regulatory body having jurisdiction over the Company or otherwise, the Indenture will constitute the legally valid and binding obligation of the Company, enforceable against the Company in accordance with its terms.

        Our opinions are subject to: (i) the effect of bankruptcy, insolvency, reorganization, preference, fraudulent transfer, moratorium or other similar laws relating to or affecting the rights and remedies of creditors; (ii) the effect of general principles of equity, whether considered in a proceeding in equity or at law (including the possible unavailability of specific performance or injunctive relief), concepts of materiality, reasonableness, good faith and fair dealing, and the discretion of the court before which a proceeding is brought; (iii) the invalidity under certain circumstances under law or court decisions of provisions providing for the indemnification of or contribution to a party with respect to a liability where such indemnification or contribution is contrary to public policy; and (iv) we express no opinion as to (a) any provision for liquidated damages, default interest, late charges, monetary penalties, make-whole premiums or other economic remedies to the extent such provisions are deemed to constitute a penalty; (b) consents to, or restrictions upon, governing law, jurisdiction, venue, arbitration, remedies, or judicial relief; (c) the waiver of rights or defenses contained in Section 4.06 of the Indenture; (d) any provision requiring the payment of attorneys' fees, where such payment is contrary to law or public policy; (e) advance waivers of claims, defenses, rights granted by law, or notice, opportunity for hearing, evidentiary requirements, statutes of limitation, trial by jury or at law, or other procedural rights; (f) waivers of broadly or vaguely stated rights; (g) covenants not to compete; (h) provisions for exclusivity, election or cumulation of rights or remedies; (i) provisions authorizing or validating conclusive or discretionary determinations; (j) grants of setoff rights; (k) provisions to the effect that a guarantor is liable as a primary obligor, and not as a surety; (l) proxies, powers and trusts; (m) provisions prohibiting, restricting, or requiring consent to assignment or transfer of any right or property; and (n) the severability, if invalid, of provisions to the foregoing effect.

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        In addition, we express no opinion with respect to (i) whether acceleration of the Debt Securities may affect the collectibility of that portion of the stated principal amount thereof that might be determined to constitute unearned interest thereon, (ii) compliance with laws relating to permissible rates of interest, (iii) the creation, validity, perfection or priority of any security interest, mortgage, or lien, or (iv) any provision to the extent it requires any party to indemnify any other person against loss in obtaining the currency due following a court judgment in another currency.

        We have not been requested to express and, with your consent, do not render any opinion as to the applicability to the obligations of the Company under the Indenture or the Debt Securities of Sections 547 and 548 of the United States Bankruptcy Code or applicable state law (including, without limitation, Article 10 of the New York Debtor and Creditor Law) relating to preferences and fraudulent transfers and obligations.

        With your consent, we have assumed (a) that the Indenture and the Debt Securities (collectively, the "Documents") will have been duly authorized, executed and delivered by the parties thereto other than the Company, (b) that the Documents will constitute legally valid and binding obligations of the parties thereto other than the Company, enforceable against each of them in accordance with their respective terms, and (c) that the status of the Documents as legally valid and binding obligations of the parties will not be affected by any (i) breaches of, or defaults under, agreements or instruments, (ii) violations of statutes, rules, regulations or court or governmental orders, or (iii) failures to obtain required consents, approvals or authorizations from, or make required registrations, declarations or filings with, governmental authorities.

        This opinion is for your benefit in connection with the Registration Statement and may be relied upon by you and by persons entitled to rely upon it pursuant to the applicable provisions of the Act. We consent to your filing this opinion as an exhibit to the Registration Statement and to the reference to our firm contained in the Prospectus under the heading "Legal Matters." In giving such consent, we do not thereby admit that we are in the category of persons whose consent is required under Section 7 of the Act or the rules and regulations of the Commission thereunder.

Very truly yours,

/s/ Latham & Watkins LLP

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