Infineon Files Counterclaim Against Volterra Semiconductor

Neubiberg, Germany – December 18, 2008 – Infineon Technologies AG (FSE/NYSE: IFX) announced that Infineon Technologies North America Corporation and Primarion, Inc., a wholly owned subsidiary of Infineon Technologies North America Corporation, today filed a counterclaim against Volterra Semiconductor Corporation alleging fraud on the United States Patent and Trademark Office, as well as Antitrust Violations. Primarion and Infineon Technologies North America have also included counterclaims alleging that the Volterra patents in suit are invalid and not infringed by them. In their counterclaim, Primarion and Infineon Technologies North America allege that the first-named inventor, Anthony J. Stratakos, identified on Volterra’s website as a founder and Chief Scientist, failed to disclose his own 1995 publication to the Patent Office when he filed his applications for U.S. Patent Nos. 6,020,729 and 6,225,795 (both entitled “Discrete-Time Sampling of Data For Use In Switching Regulators”) two years later in 1997. The counterclaim further alleges that the Stratakos 1995 paper was published by the University of California at Berkeley, and that the paper discloses the alleged invention claimed in the two Volterra patents. Primarion and Infineon Technologies North America intend to vigorously prosecute their case against Volterra, and deny that the Volterra patents are either valid or infringed. Primarion and Infineon Technologies North America filed the counterclaim against Volterra in the US District Court for the Northern District of California. Volterra had brought a patent infringement action against Primarion and Infineon Technologies North America in the same court on November 12, 2008. For further information on Primarion please see www.primarion.com

About Infineon Infineon Technologies AG, Neubiberg, Germany, offers semiconductor and system solutions addressing three central challenges to modern society: energy efficiency, communications, and security. In the 2007 fiscal year (ending September), the company reported sales of Euro 7.7 billion (including Qimonda sales of Euro 3.6 billion) with approximately 43,000 employees worldwide (including approximately 13,500 Qimonda employees). With a global presence, Infineon operates through its subsidiaries in the U.S. from Milpitas, CA, in the Asia-Pacific region from Singapore, and in Japan from Tokyo. Infineon is listed on the Frankfurt Stock Exchange and on the New York Stock Exchange (ticker symbol: IFX).Further information is available at www.infineon.com.