Exhibit 5.1

December 6, 2000

Microchip Technology Incorporated
2355 West Chandler Boulevard
Chandler, Arizona  85224

     RE:  Registration  Statement on Form S-8 For Issuance of Common Stock Under
          the Microchip  Technology  Incorporated  Employee  Stock Purchase Plan
          (the "Purchase Plan") and the Microchip  Technology  Incorporated 1997
          Nonstatutory Stock Option Plan (the "Stock Option Plan")

Gentlemen:

I refer  you to your  registration  on Form S-8 (the  "Registration  Statement")
under the  Securities  Act of 1933, as amended,  of (i) 300,000 shares of Common
Stock under the Purchase Plan,  and (ii) 8,250,000  shares of Common Stock under
the Stock Option Plan. I advise you that,  in my opinion,  when such shares have
been issued and sold pursuant to the applicable  provisions of the Purchase Plan
and the Stock Option Plan, and in accordance  with the  Registration  Statement,
such shares will be validly issued,  fully-paid and non-assessable shares of the
Company's Common Stock, par value $.001 per share.

I hereby consent to the filing of this opinion as an exhibit to the Registration
Statement.

Sincerely yours,

/s/ Mary K. Simmons

Mary K. Simmons, Esq.
Vice President, General Counsel and Secretary
Microchip Technology Incorporated