In pretrial sparring this week, Rambus introduced corrections to its SDRAM patents in an effort to offset U.S. District Court Judge Robert Payne's ruling that the patents relate only to multiplexed memory bus lines.

Payne's limited reading of the patents is a key point for Infineon, which doesn't use the multiplexed lines in its SDRAM chips and is asking that Rambus' infringement claims be dismissed based on the judge's narrow interpretation.

The admission of the patent corrections, which the U.S. Patent and Trademark Office (PTO) approved on Jan. 2, has been contested by Infineon on the grounds that they were granted five months after Rambus filed suit against the Munich, Germany, chip maker.

In another wrinkle, Infineon attorneys will try to render Rambus' patents invalid by claiming that the company sought to deceive the PTO when filing its SDRAM patent applications. In a pretrial summary of its case released this week, Infineon attorneys said they will seek to prove that Rambus knew of, but failed to disclose to the PTO, prior inventions and existing patents.

Infineon is also expected to introduce evidence from its depositions of Rambus executives and attorneys regarding the company's alleged attempts to keep its SDRAM patent applications hidden from the JEDEC open standards panel.

Rambus' case, as outlined to Judge Payne in the summary, will seek to prove that Infineon knew about Rambus' intellectual property because of confidential 1991 licensing negotiations between the companies before the JEDEC SDRAM panel convened.

Moreover, Rambus will argue that Infineon and other chip makers on the JEDEC panel pirated important SDRAM innovations gleaned from the licensing talks, data that was later incorporated into the JEDEC standard.

Pretrial presentations by both sides centered around Rambus' original synchronous-interface patent application, which was filed in 1990 but was frequently amended and divided into other patent claims. Rambus said it will show that the 1990 patent claim predated the JEDEC SDRAM standard.

Infineon said its evidence will prove the application had virtually no relation to SDRAM, and that only amended patents filed by Rambus in 1996 and 1997-after the JEDEC standard was approved-added SDRAM details.