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                                                                     EXHIBIT 5.1


                                HALE AND DORR LLP
                               COUNSELLORS AT LAW


                  60 STATE STREET, BOSTON, MASSACHUSETTS 02109
                         617-526-6000 o FAX 617-526-5000


                                             December 18, 1998

Analog Devices, Inc.
One Technology Way
Norwood, Massachusetts 02062

         Re:  Analog Devices Canada Stock Option and Deferred Stock Plan   
              ----------------------------------------------------------
      

Ladies and Gentlemen:

         This opinion is furnished to you in connection with a Registration
Statement on Form S-8 (the "Registration Statement") to be filed with the
Securities and Exchange Commission (the "Commission") under the Securities Act
of 1933, as amended (the "Securities Act"), for the registration of 119,706
shares of Common Stock, $.16 2/3 par value per share (the "Shares"), of Analog
Devices, Inc., a Massachusetts corporation (the "Company"), issuable under the
Company's Analog Devices Canada Stock Option and Deferred Stock Plan (the
"Plan").

         We have examined the Restated Articles of Organization and the By-laws
of the Company and originals, or copies certified to our satisfaction, of all
pertinent records of the meetings of the directors and stockholders of the
Company, the Registration Statement and such other documents relating to the
Company as we have deemed material for the purposes of this opinion.

         In our examination of the foregoing documents, we have assumed the
genuineness of all signatures and the authenticity of all documents submitted to
us as originals, the conformity to original documents of all documents submitted
to us as copies, the authenticity of the originals of such latter documents and
the legal competence of all signatories to such documents.

         We express no opinion herein as to the laws of any state or
jurisdiction other than the state laws of the Commonwealth of Massachusetts and
the federal laws of the United States of America.

         Based upon and subject to the foregoing, we are of the opinion that the
Company has duly authorized for issuance the Shares, and the Shares, when issued
and paid for in accordance with the terms of the Plan and at a price per share
in excess of the par value per share for such Shares, will be validly issued,
fully-paid and nonassessable.






WASHINGTON, D.C.                   BOSTON, MA                       London, UK*
- --------------------------------------------------------------------------------

              HALE AND DORR LLP INCLUDES PROFESSIONAL CORPORATIONS
  *BROBECK HALE AND DORR INTERNATIONAL (AN INDEPENDENT JOINT VENTURE LAW FIRM)



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Analog Devices, Inc.
December 18, 1998
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         It is understood that this opinion is to be used only in connection
with the offer and sale of the Shares while the Registration Statement is in
effect.

         This opinion is based upon currently existing statutes, rules,
regulations and judicial decisions, and we disclaim any obligation to advise you
of any change in any of these sources of law or subsequent legal or factual
developments which might affect any matters or opinions set forth herein.

         Please note that we are opining only as to the matters expressly set
forth herein, and no opinion should be inferred as to any other matters.

         We hereby consent to the filing of this opinion with the Commission as
an exhibit to the Registration Statement in accordance with the requirements of
Item 601(b)(5) of Regulation S-K under the Securities Act. In giving such
consent, we do not hereby admit that we are in the category of persons whose
consent is required under Section 7 of the Securities Act or the rules and
regulations of the Commission.





                                        Very truly yours,



                                        /s/ HALE AND DORR LLP
                                        ------------------------------------
                                        HALE AND DORR LLP