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^*

Ueunten Paul

(Last)

(First)

(Middle)

6409 GUADALUPE MINES ROAD

(Street)

SAN JOSE

95120

(City)

(State)

(Zip)

2. Date of Event Requiring Statement (Month/Day/Year)
10/25/2007

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)
	Sr. V.P. Design Engineering

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)
Common Stock	69,500⁽¹⁾	D
Common Stock	153,556	I	Ueunten Trust I
Common Stock	123,900	I	Ueunten Trust II
Common Stock	40,550	I	Ueunten Trust III
Common Stock	40,550	I	Ueunten Trust IV

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)
1. Title of Derivative Security (Instr. 4)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares	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)
Incentive Stock Option (right to buy)	07/15/2003⁽²⁾	07/17/2012	Common Stock	58,000	$1.2	D
Incentive Stock Option (right to buy)	09/10/2004⁽³⁾	09/11/2013	Common Stock	40,000	$1.2	D
Incentive Stock Option (right to buy)	01/26/2006⁽⁴⁾	01/26/2015	Common Stock	23,271	$7.77	D
Incentive Stock Option (right to buy)	06/15/2006⁽⁵⁾	06/15/2015	Common Stock	19,238	$9.32	D
Non-Qualified Stock Option (right to buy)	01/26/2006⁽⁴⁾	01/26/2015	Common Stock	3,729	$7.77	D
Non-Qualified Stock Option (right to buy)	06/15/2006⁽⁵⁾	06/15/2015	Common Stock	60,762	$9.32	D
Non-Qualified Stock Option (right to buy)	10/26/2008⁽⁶⁾	10/26/2013	Common Stock	25,000	$11.85	D
Non-Qualified Stock Option (right to buy)	07/27/2009⁽⁷⁾	10/26/2013	Common Stock	77,000	$16	D

Explanation of Responses:

1. Includes 9,500 restricted stock units granted on 7/27/07 that vest in increments of 50% of each on 7/27/08 and 7/27/09. Also includes 60,000 shares held in an Individual Retirement Account for the benefit of the Reporting Person.

2. A total of 94,000 shares were granted on 7/17/02. Twenty five percent (25%) of the shares vested on 7/15/03 and 1/48th of the shares vested each month thereafter.

3. A total of 40,000 shares were granted on 9/11/03. Twenty five percent (25%) of the shares vested on 9/10/04 and 1/48th of the shares vested each month thereafter.

4. A total of 27,000 shares were granted on 1/26/05. Twenty five percent (25%) of the shares vested on 1/26/06 and 1/48th of the shares vests each month thereafter.

5. A total of 80,000 shares were granted on 6/15/05. Twenty five percent (25%) of the shares vested on 6/15/06 and 1/48th of the shares vests each month thereafter.

6. A total of 25,000 shares were granted on 10/26/06. Fifty percent (50%) of the shares vest twenty-four (24) months after the grant date, and 1/48 of the shares vest monthly thereafter on the same day of the month as the grant date.

7. A total of 77,000 shares were granted on 7/27/07. Fifty percent (50%) of the shares vest twenty-four (24) months after the grant date, and 1/48 of the shares vest monthly thereafter on the same day of the month as the grant date.

	Paul Ueunten	11/07/2007
	** 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.
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