SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549
SCHEDULE 13G
(Rule 13d-102)
INFORMATION TO BE INCLUDED IN STATEMENTS FILED PURSUANT
TO RULES 13d-1(b), (c) AND (d) AND AMENDMENTS THERETO FILED
PURSUANT TO 13d-2
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NOVEMBER 3, 2006
CHECK THE APPROPRIATE BOX TO DESIGNATE THE RULE
PURSUANT TO WHICH THIS SCHEDULE IS FILED:
[ ] Rule 13d-1(b)
[ x ] Rule 13d-1(c)
[ ] Rule 13d-1(d)
MONOLITHIC POWER SYSTEMS INC.
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(Name of Issuer)
COMMON STOCK
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(Title of Class of Securities)
609839105
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(CUSIP Number)
CUSIP Number 609839105
1) NAME OF REPORTING PERSON
S.S. OR I.R.S. IDENTIFICATION NO. OF ABOVE PERSON
SELIGMAN TECH SPECTRUM (MASTER) FUND
98-0361992
2) CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP
(a) / /
(b) / x /
3) SEC USE ONLY
4) CITIZENSHIP OR PLACE OF ORGANIZATION
CAYMAN ISLANDS
(5) SOLE VOTING POWER -0-
NUMBER OF SHARES
BENEFICIALLY OWNED (6) SHARED VOTING POWER 1,578,305*
BY EACH REPORTING
PERSON WITH (7) SOLE DISPOSITIVE POWER -0-
(8) SHARED DISPOSITIVE POWER 1,578,305*
9) AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
1,578,305*
10) CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES / /
11) PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)
5.23%
12) TYPE OF REPORTING PERSON
CO
* J. & W. Seligman & Co. Incorporated (JWS) is the investment adviser
for the reporting person, and the shares reported herein will be included in
the Schedule 13G filed by JWS with respect to the issuer to the extent
such shares are still deemed to be beneficially owned by JWS as of the
reporting date.
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Item 1(a) Name of Issuer:
MONOLITHIC POWER SYSTEM INC.
Item 1(b) Address of Issuer's Principal Executive Offices:
983 UNIVERSITY AVENUE
BLDG A
LOS GATOS, CA 95032
Item 2(a) Name of Person Filing:
SELIGMAN TECH SPECTRUM (MASTER) FUND
Item 2(b) Address or Principal Business Office or, if none, Residence:
C/o J. & W. SELIGMAN & CO. INCORPORATED
100 PARK AVENUE
NEW YORK, NEW YORK 10017
Item 2(c) Citizenship:
CAYMAN ISLANDS
Item 2(d) Title of Class of Securities:
COMMON STOCK
Item 2(e) CUSIP Number:
609839105
Item 3 If this statement is filed pursuant to Rules 13d-1(b), or 13d-2(b),
check whether the person is filing as a:
Item 4 Ownership.
Incorporated by reference to Items (5)-(9) and (11) of the cover
page.
Item 5 Ownership of Five Percent or Less of a Class.
NOT APPLICABLE
Item 6 Ownership of More than Five Percent on Behalf of Another Person.
NOT APPLICABLE
Item 7 Identification and Classification of the Subsidiary which acquired
the security being reported on by the Parent Holding Company.
NOT APPLICABLE
Item 8 Identification and Classification of Members of the Group.
NOT APPLICABLE
Item 9 Notice of Dissolution of Group.
NOT APPLICABLE
Item 10 Certification
By signing below I certify that, to the best of my
knowledge and belief, the securities referred to above
were not acquired and are not held for the purpose of
or with the effect of changing or influencing the control of
the issuer of such securities and were not acquired and are not
held in connection with or as a participant in any transaction
having such purpose or effect.
SIGNATURE
After reasonable inquiry and to the best of my knowledge and belief,
I certify that the information set forth in this statement is true,
complete and correct.
DATE: January 16, 2007
SELIGMAN TECH SPECTRUM (MASTER) FUND
BY /s/ LAWRENCE P. VOGEL
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Name: LAWRENCE P. VOGEL
Title: AUTHORIZED PERSON
EXHIBIT
EXHIBIT 1
Seligman Tech Spectrum (Master) Fund
(the "Company")
CERTIFICATE
The undersigned certifies that he is a Managing Director
of J. & W. Seligman & Co. Incorporated, the Company's investment
manager (the "Manager"), and that he is authorized to execute this
certificate on behalf of the Company and further certifies on behalf
of the Company that the following is (in relevant part) a true and
complete copy of resolutions duly adopted by the Board of Directors
of the Company as of December 21, 2006, and such resolutions have not
been rescinded or amended and remain in full force and effect on the
date hereof:
FURTHER RESOLVED, that each person named below be, and hereby
is, designated as an authorized person (each an "Authorized Person")
to act on behalf of the Company as from time to time authorized by
the Board of Directors (subject to the limitations provided herein or
from time to time):
Joseph Cheung
Frank J. Nasta
David F. Stein
Richard C. Dluzniewski
Richard M. Potocki
Edward G. Stromberg III
Thomas J. Figueira
Thomas G. Rose
Lawrence P. Vogel
Paul B. Goucher
Julie Rosenberg
Yvonne R. Walker
John Guancione
Rodney G.D. Smith
Brian T. Zino
.. . .
FURTHER RESOLVED, that any Director of the Company and each
Authorized Person be, and the same hereby are, authorized to perform
on behalf of the Company any and all such acts as they or any of he
or she may deem necessary or advisable in connection with the
organization and operation of the Company (including providing
instructions to the Manager, PFPC, Morgan Stanley & Co. Incorporated,
SAI and any other service providers and executing contracts on behalf
of the Company) or the offer and listing of the shares of the Company
or in order to comply with all applicable laws or regulations and in
connection therewith to execute and file all requisite papers and
documents including but not limited to applications, reports,
irrevocable consents and appointments of attorneys for service of
process, and the execution by such Director or Authorized Person of
any such paper or document or the doing by him or her of any act in
connection with the foregoing matters shall conclusively establish his
or her authority therefor from the Company and the approval and
ratification of the Company of the papers and documents so executed and
actions so taken.
IN WITNESS WHEREOF, I have hereunto set my name as of this 11th
day of January, 2007.
/s/ Paul B Goucher
Paul B Goucher
Authorized Person