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                                                                 Exhibit 10.21



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        PROPRIETARY INFORMATION, CONFIDENTIALITY AND INVENTIONS AGREEMENT

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To:      HITTITE MICROWAVE CORPORATION
         12 Elizabeth Drive
         Chelmsford, Massachusetts 01824         As of March 1, 2001

         I, the undersigned, in consideration of and as a condition of my
employment by Hittite Microwave Corporation (the "Company"), and for other good
and valuable consideration, the receipt and sufficiency of which is hereby
acknowledged, hereby agree as follows:

         1. CONFIDENTIALITY. I agree to keep confidential, except as the Company
may otherwise consent in writing, and, as may be necessary in the ordinary
course of performing my duties to the Company, not to disclose or make any use
of at any time either during or subsequent to my employment, any Inventions (as
hereinafter defined), trade secrets, confidential information, knowledge, data
or other information of the Company relating to products, processes, know-how,
designs, formulas, test data, customer lists, business plans, marketing plans
and strategies, pricing strategies, or other subject matter pertaining to any
business of the Company or any of its affiliates or confidential or proprietary
information of any third parties subject to a duty on the part of the Company to
maintain the confidentiality of such information, which I may produce, obtain,
or otherwise acquire during the course of my employment, except as herein
provided. I further agree not to deliver, reproduce or in any way allow any such
trade secrets, confidential information, knowledge, data or other information or
any documentation relating thereto, to be delivered to or used by any third
parties without specific direction or consent of a duly authorized
representative of the Company.

         2. CONFLICTING EMPLOYMENT; RETURN OF CONFIDENTIAL MATERIAL. I agree
that during my employment with the Company I will not engage in any other
employment, occupation, consulting or other activity relating to the business in
which the Company is now or may hereafter become engaged, or which would
otherwise conflict with my obligations to the Company. In the event my
employment with the Company terminates for any reason whatsoever, I agree to
promptly surrender and deliver to the Company all records, materials, equipment,
drawings, documents and data which I may obtain or produce during the course of
my employment, and I further agree that I will not take with me any description
containing or pertaining to any confidential information, knowledge or data of
the Company which I may produce or obtain during the course of my employment.

         3. ASSIGNMENT OF INVENTIONS.

         3.1 I hereby acknowledge and agree that the Company is the owner of all
Inventions (as hereinafter defined). In order to protect the Company's rights to
such Inventions, by executing this Agreement I hereby irrevocably assign to the
Company all my right, title and interest in and to all Inventions.

         3.2 For purposes of this Agreement, "Inventions" shall mean all
discoveries, processes, designs, technologies, devices, or improvements in any
of the foregoing or other


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ideas, whether or not patentable and whether or not reduced to practice, made or
conceived by me (whether solely or jointly with others) during the period of my
employment with the Company which relate in any manner to the actual or
demonstrably anticipated business, work, or research and development of the
Company, or result from or are suggested by any tasks assigned to me or any work
performed by me for or on behalf of the Company.

         3.3 Any discovery, process, design, technology, device, or improvement
in any of the foregoing or other ideas, whether or not patentable and whether or
not reduced to practice, made or conceived by me (whether solely or jointly with
others) which I develop entirely on my own time not using any of the Company's
equipment, supplies, facilities, or trade secret information ("Personal
Invention") is excluded from this Agreement provided such Personal Invention (a)
does not relate to the actual or demonstrably anticipated business, research and
development of the Company; and (b) does not result, directly or indirectly,
from any work performed by me for the Company.

         4. DISCLOSURE OF INVENTIONS. I agree that in connection with any
Invention, I will promptly disclose such Invention to my immediate superior at
the Company in order to permit the Company to enforce its property rights to
such Invention in accordance with this Agreement. My disclosure shall be
received in confidence by the Company.

         5. PATENTS AND COPYRIGHTS: EXECUTION OF DOCUMENTS.

         5.1 Upon request, I agree to assist the Company or its nominee (at its
expense) during and at any time subsequent to my employment in every reasonable
way to obtain for its own benefit patents and copyrights for Inventions in any
and all countries. Such patents and copyrights shall be and remain the sole and
exclusive property of the Company or its nominee. I agree to perform such lawful
acts as the Company deems to be necessary to allow it to exercise all right,
title and interest in and to such patents and copyrights.

         5.2 In connection with this Agreement, I agree to execute, acknowledge
and deliver to the Company or its nominee upon request and at its expense all
documents, including assignments of title, patent or copyright applications,
assignments of such applications, assignments of patents or copyrights upon
issuance, as the Company may determine necessary or desirable to protect the
Company's or its nominee's interest in Inventions, and/or to use in obtaining
patents or copyrights in any and all countries and to vest title thereto in the
Company or its nominee to any of the foregoing.

         6. MAINTENANCE OF RECORDS. I agree to keep and maintain adequate and
current written records of all Inventions made by me (in the form of notes,
sketches, drawings and other records as may be specified by the Company), which
records shall be available to and remain the sole property of the Company at all
times.

         7. PRIOR INVENTIONS. It is understood that all Personal Inventions, if
any, whether patented or unpatented, which I made prior to my employment by the
Company, are excluded from this Agreement. To preclude any possible uncertainty,
I have set forth on Schedule A attached hereto a complete list of all of my
prior Personal Inventions, including numbers of all patents and patent
applications and a brief description of all unpatented Personal Inventions


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which are not the property of a previous employer. I represent and covenant that
the list is complete and that, if no items are on the list, I have no such prior
Personal Inventions. I agree to notify the Company in writing before I make any
disclosure or perform any work on behalf of the Company which appears to
threaten or conflict with proprietary rights I claim in any Personal Invention.
In the event of my failure to give such notice, I agree that I will make no
claim against the Company with respect to any such Personal Invention.

         8. OTHER OBLIGATIONS. I acknowledge that the Company from time to time
may have agreements with other persons or with the U.S. Government or agencies
thereof, which impose obligations or restrictions on the Company regarding
Inventions made during the course of work thereunder or regarding the
confidential nature of such work. I agree to be bound by all such obligations
and restrictions and to take all action necessary to discharge the Company's
obligations.

         9. TRADE SECRETS OF OTHERS. I represent that my performance of all the
terms of this Agreement and as an employee of the Company does not and will not
breach any agreement to keep confidential proprietary information, knowledge or
data acquired by me in confidence or in trust prior to my employment with the
Company or any other agreement with any previous employer or other party, and I
will not disclose to the Company, or induce the Company to use, any confidential
or proprietary information or material belonging to any previous employer or
others. I agree not to enter into any agreement either written or oral in
conflict herewith.

         10. Without limiting the remedies available to the Company, I
acknowledge that a breach of any of the terms of this Agreement could result in
irreparable injury to the Company for which there might be no adequate remedy at
law and that, in the event of such a breach or threat thereof, the Company shall
be entitled to obtain a temporary restraining order and/or a preliminary
injunction and a permanent injunction restraining me from engaging in any
activities prohibited by this Agreement or such other equitable relief as may be
required to enforce specifically any of the covenants of this Agreement.

         11. MODIFICATION. I agree that any subsequent change or changes in my
employment duties, salary or compensation or, if applicable, in any Employment
Agreement between the Company and me, shall not affect the validity or scope of
this Agreement.

         12. SUCCESSORS AND ASSIGNS. This Agreement shall be binding upon my
heirs, executors, administrators or other legal representatives and is for the
benefit of the Company, its successors and assigns.

         13. INTERPRETATION. IT IS THE INTENT OF THE PARTIES THAT in case any
one or more of the provisions contained in this Agreement shall, for any reason,
be held to be invalid, illegal or unenforceable in any respect, such invalidity,
illegality or unenforceability shall not affect the other provisions of this
Agreement, and this Agreement shall be construed as if such invalid, illegal or
unenforceable provision had never been contained herein. MOREOVER, IT IS THE
INTENT OF THE PARTIES THAT in case any one or more of the provisions contained
in this Agreement shall for any reason be held to be excessively broad as to
duration, geographical scope, activity or subject, such provision shall be
construed by dating and reducing it in


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accordance with a judgment of a court of competent jurisdiction, so as to be
enforceable to the extent compatible with applicable law.

         14. WAIVERS. If either party should waive any breach of any provision
of this Agreement, he or it shall not thereby be deemed to have waived any
preceding or succeeding breach of the same or any other provision of this
Agreement.

         15. COMPLETE AGREEMENT, AMENDMENTS. I acknowledge receipt of this
Agreement, and agree that with respect to the subject matter thereof it is my
entire agreement with the Company, superseding any previous oral or written
communications, representations, understandings, or agreements with the Company
or any officer or representative thereof. I understand and acknowledge that this
Agreement is an agreement of proprietary information, confidentiality and
inventions, and that this is not a contract for any term of employment and does
not modify the at-will status of the employment relationship. I further
acknowledge that this Agreement creates no contractual terms of employment other
than those specifically enumerated herein. Any amendment to this Agreement or
waiver by either party of any right hereunder shall be effective only if
evidenced by a written instrument executed by the parties hereto, and, in the
case of the Company, upon written authorization of the Company's Board of
Directors.

         16. HEADINGS. The headings of the sections hereof are inserted for
convenience only and shall not be deemed to constitute a part hereof nor to
affect the meaning thereof.

         17. COUNTERPARTS. This Agreement may be signed in two counterparts,
each of which shall be deemed an original and both of which shall together
constitute one agreement.

         18. GOVERNING LAW. This Agreement shall be governed and construed under
Massachusetts Law.

                                    EMPLOYEE

                                    /s/ WILLIAM W. BOECKE
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                                    Accepted and Agreed:

                                    HITTITE MICROWAVE CORPORATION

                                    By: /s/ WILLIAM SYLVANOWICZ
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                                        Duly Authorized


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