Court Enters Judgment That Monolithic Power Systems does not infringe O2 Micro Patent, Sets Aside $12 Million Jury Verdict, Awards $2.7 Million Plus Cost

LOS GATOS, Calif. – November 11, 2005 – Monolithic Power Systems, Inc. (MPS) (Nasdaq: MPWR), a leading fabless manufacturer of high-performance analog and mixed-signal semiconductors, today announced that judgment has been entered in its case with O2 Micro International, Ltd. (Nasdaq: OIIM) in the United States District Court for the Northern District of California. The court entered judgment that MPS does not infringe O2 Micro's '615 patent, confirming a prior summary judgment in favor of MPS. In an opinion, the judge set aside the $12 million jury verdict rendered July 18, 2005 on O2 Micro's trade secret claims, and instead awarded O2 Micro $2.7 million, comprised of a royalty of $900,000 plus exemplary damages of $1.8 million, plus costs. The judge also denied O2 Micro's requests for an injunction and attorneys’ fees and ruled that MPS did not act improperly in obtaining its patents. MPS is reviewing the judge's opinion and considering its options, including post-trial motions and appeal.

About Monolithic Power Systems
Monolithic Power Systems, Inc. (MPS) develops and markets proprietary, advanced analog and mixed-signal semiconductors. The company's advanced process technology and highly experienced analog designers provide high-performance power management integrated circuits (ICs) for automotive, industrial, consumer, computing, and communications products. MPS partners with world-class foundries to deliver high-quality, cost-effective solutions to meet the demanding standards set by its customers. Founded in 1997 and headquartered in Los Gatos, California, the company has expanded its global presence with sales offices in Taiwan, China, Korea, and Japan, which operate under MPS International, Ltd.