TOKYO (04/12/2000) - Computer memory designer Rambus Inc. turned up the heat in a patent dispute with Hitachi Ltd. on Monday by filing suit against the company in Europe.

Rambus filed a suit in the District Court in Mannheim, Germany, against Hitachi Europe GmbH, the U.S. based company said in a statement yesterday.

The move is the latest in a battle that began in January when Rambus filed in the U.S. Federal District Court in Delaware against Hitachi and its Hitachi Semiconductor (America) Ltd. subsidiary to prevent the sale of certain products, including memory chips and its SH microprocessors, in the U.S. market. [See "Rambus Sues Hitachi over Patent Infringement," Jan. 17].

In the January filing Rambus alleged Hitachi's PC100 SDRAM, PC133 SDRAM, DDR SDRAM (double data rate SDRAM), SGRAM (synchronous graphics RAM) and DIMM modules, as well as Hitachi's SH-2, SH-3, SH-4 and SH-5 microprocessors infringe upon four of its patents.

In late March Rambus filed documents with the U.S. International Trade Commission and requested it look into the alleged patent infringement and sought to block sales of Sega Enterprises Ltd.'s Dreamcast games machine, which uses the SH microprocessor, in the U.S. market. [See "Rambus Targets Dreamcast Shipments in Patent Spat," Mar. 24].

Rambus' latest move in Germany seeks to halt the "importation, sale, manufacture and use of Hitachi SDRAM and DDR SDRAM memory devices" which the company alleges infringe upon a patent it holds, European Patent EP 0 525 068.

Rambus said the patent covers fundamental technology relating to synchronous memory devices.

Rambus has developed its own memory interface technology and licensed it to around 30 companies, including Hitachi, but the Japanese company has yet to produce any chips based on the system. That fact is not lost on Rambus and in a statement concerning its original lawsuit company chief executive officer Geoff Tate said, "To date Hitachi has not produced or marketed any such RDRAM-compatible products."

Rambus, in Mountain View, California, can be found on the Web at http://www.rambus.com/. Hitachi Ltd., in Tokyo, can be found on the Web at http://www.hitachi.co.jp/.