MONOLITHIC POWER SYSTEMS INC — Director's Dealing 2010

Mar 25, 2010

SEC Form 4 — Statement of Changes in Beneficial Ownership

Issuer: MONOLITHIC POWER SYSTEMS INC (MPWR)
CIK: 0001280452
Period of Report: 2010-02-16

Reporting Person: Tseng Saria (VP & General Counsel)

Non-Derivative Transactions

Date	Security	Code	Shares	Price	A/D	Holdings After	Ownership
2010-02-16	Common Stock	J	916	$18.411	Acquired	16054	Direct
2010-03-25	Common Stock	M	6800	$16	Acquired	52854	Direct
2010-03-25	Common Stock	S	9533	$23.2172	Disposed	43321	Direct

Derivative Transactions

Date	Security	Exercise Price	Code	Shares	A/D	Expiration	Underlying	Ownership
2010-03-25	Non-Qualified Stock Option (right to buy)	$16	M	6800	Disposed	2014-07-27	Common Stock (6800)	Direct

Footnotes

F1: Acquired through the Company's qualified ESPP program.

F2: In accordance with the reporting person's 10b5-1 trading plan.