SEC FORM 3 SEC Form 3
FORM 3 UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

INITIAL STATEMENT OF BENEFICIAL OWNERSHIP OF SECURITIES

Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934
or Section 30(h) of the Investment Company Act of 1940
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1. Name and Address of Reporting Person*
Rao Meera

(Last) (First) (Middle)
6409 GUADALUPE MINES ROAD

(Street)
SAN JOSE CA 95120

(City) (State) (Zip)
2. Date of Event Requiring Statement (Month/Day/Year)
02/09/2010
3. Issuer Name and Ticker or Trading Symbol
MONOLITHIC POWER SYSTEMS INC [ MPWR ]
4. Relationship of Reporting Person(s) to Issuer
(Check all applicable)
Director 10% Owner
X Officer (give title below) Other (specify below)
VP of Finance, Corp Controller
5. If Amendment, Date of Original Filed (Month/Day/Year)
6. Individual or Joint/Group Filing (Check Applicable Line)
X Form filed by One Reporting Person
Form filed by More than One Reporting Person
Table I - Non-Derivative Securities Beneficially Owned
1. Title of Security (Instr. 4) 2. Amount of Securities Beneficially Owned (Instr. 4) 3. Ownership Form: Direct (D) or Indirect (I) (Instr. 5) 4. Nature of Indirect Beneficial Ownership (Instr. 5)
Table II - Derivative Securities Beneficially Owned
(e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 4) 2. Date Exercisable and Expiration Date (Month/Day/Year) 3. Title and Amount of Securities Underlying Derivative Security (Instr. 4) 4. Conversion or Exercise Price of Derivative Security 5. Ownership Form: Direct (D) or Indirect (I) (Instr. 5) 6. Nature of Indirect Beneficial Ownership (Instr. 5)
Date Exercisable Expiration Date Title Amount or Number of Shares
Non-Qualified Stock Option (right to buy) 01/05/2010(1) 01/05/2016 Common Stock 70,000 13.53 D
Explanation of Responses:
1. A total of 70,000 shares were granted on 1/5/2009. Twenty five percent (25%) of the shares vested twelve (12) months after the grant date, and 1/48th of the shares vest monthly thereafter.
By: Rick Neely For: Meera Rao 02/09/2010
** Signature of Reporting Person Date
Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
* If the form is filed by more than one reporting person, see Instruction 5 (b)(v).
** Intentional misstatements or omissions of facts constitute Federal Criminal Violations See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.
Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB Number.
LIMITED POWER OF ATTORNEY
FOR MONOLITHIC POWER SYSTEMS
SECTION 16(a) FILINGS
Know all by these presents, that the undersigned, Meera Rao, hereby 
constitutes and appoints each of Michael Hsing, Rick Neely and Saria 
Tseng, signing singly, the undersigned's true and lawful 
attorney-in-fact to:
(1) Complete and execute for and on behalf of the undersigned, in the 
undersigned's capacity as an officer, director and/or stockholder of 
Monolithic Power Systems, Inc. (the "Company"), Forms ID, 3, 4, and 
5 and other forms and all amendments thereto as such attorney-in-fact 
shall in his or her discretion determine to be required or advisable 
in accordance with Section 16(a) of the Securities Exchange Act of 
1934 and the rules and regulations promulgated thereunder, or any 
successor laws and regulations, as consequence of the undersigned's 
ownership, acquisition or disposition of securities of the Company; 
(2) Do and perform any and all acts for and on behalf of the 
undersigned which may be necessary or desirable to complete and execute 
any such forms or amendment thereto and timely file such forms with the 
United States Securities and Exchange Commission (the "SEC") and any 
stock exchange or similar authority; and
(3) Take any other action
 of any type whatsoever which, in the opinion 
of such attorney-in-fact, may be necessary or desirable in connection 
with the foregoing authority, it being understood that the documents 
executed by such attorney-in-fact on behalf of the undersigned pursuant 
to this Power of Attorney shall be in such form and shall contain such 
terms and conditions as such attorney-in-fact may approve.
The undersigned hereby grants to each such attorney-in-fact full power 
and authority to do and perform any and every act and thing whatsoever 
requisite, necessary, or proper to be done in the exercise of any of the 
rights and powers herein granted, as fully to all intents and purposes 
as the undersigned might or could do if personally present, with full 
power of substitution or revocation, hereby ratifying and confirming 
all that such attorney-in-fact, or such attorney-in-fact's substitute 
or substitutes, shall lawfully do or cause to be done by virtue of this 
Power of Attorney and the rights and powers herein granted. The 
undersigned acknowledges that the foregoing attorneys-in-fact, in 
serving in such capacity at the request of the undersigned, are not 
assuming, nor is the Company assuming, any of the undersigned's 
responsibilities to comply with Section 16 of the Securities Exchange 
Act of 1934.
This Power of Attorney shall remain in full force and effect until the 
undersigned is no longer required to file Forms ID, 3, 4, and 5 with 
respect to the undersigned's holdings of and transaction in securities 
of the Company, unless earlier revoked by the undersigned in a signed 
writing delivered to the Company and the foregoing attorneys-in-fact. 
This Power of Attorney may be filed with the SEC as a confirming 
statement of the authority granted herein.
IN WITNESS WHEREOF, the undersigned has caused this Power of Attorney 
to be executed as of this day of February 9, 2010.
__ Meera Rao________
Print Name of Reporting Person 

__ /s/Meera Rao________
Signature