EXHIBIT 5.1


July 19, 2002


Microchip Technology Incorporated
2355 West Chandler Blvd.
Chandler, AZ  85224-6199

     RE:  REGISTRATION STATEMENT ON FORM S-8

Ladies and Gentlemen:

I have examined the  Registration  Statement on Form S-8 to be filed by you with
the  Securities  and  Exchange  Commission  on or  about  the date  hereof  (the
"Registration   Statement")  in  connection  with  the  registration  under  the
Securities Act of 1933, as amended (the "Act"),  of 32,414 shares of your Common
Stock  issuable  under the  PowerSmart,  Inc.  1998  Stock  Incentive  Plan (the
"Plan."). Such shares of Common Stock are referred to herein as the "Shares." As
your  counsel,  I have examined the  proceedings  taken and am familiar with the
proceedings proposed to be taken by you in connection with the issuance and sale
of the Shares pursuant to the Plan.

It  is my  opinion  that,  upon  completion  of  the  actions  being  taken,  or
contemplated  by me as your  counsel to be taken by you prior to the issuance of
the  Shares  pursuant  to the  Registration  Statement  and the  Plan  and  upon
completion of the actions being taken in order to permit such transactions to be
carried out in accordance  with the securities  laws of the various states where
required,  the  Shares  will be  legally  and  validly  issued,  fully-paid  and
non-assessable.

I  consent  to  the  use of  this  opinion  as an  exhibit  to the  Registration
Statement,  and further consent to the use of my name wherever  appearing in the
Registration Statement and any amendments thereto.

Very truly yours,

/s/ Mary K. Simmons

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