Chip makers LSI and STMicroelectronics did not infringe on patents claimed by Rambus, according to a ruling by the U.S. International Trade Commission on Wednesday .
Rambus claimed the chip makers had allegedly violated patents related to chipset communication and controlling of memory and digital transmitters, ITC wrote in its judgment. The ruling reaffirms earlier findings by the ITC, which has now terminated the investigation.
ITC said some patents were unenforceable, while Rambus did prove other infringement claims against other companies.
Rambus originally filed a complaint of patent infringement against multiple companies in December 2010, and ITC initiated the investigation the next month. Rambus has since withdrawn some claims after settling with Freescale Semiconductor, Broadcom, Mediatek and Nvidia, leaving the ITC to determine whether LSI and STMicroelectronics infringed on patents.
Rambus alleged that the companies infringed on patents 6,470,405, 6,591,353 and 7,287,109, which relate to communication and controlling of memory; and patent numbers 7,602,857 and 7,715,494, which are tied to the transmission of signals in and out of memory and chipsets.
The original complaint by Rambus sought to bar the importation and sale of infringing storage, memory, integrated circuit and processor products.
Rambus is evaluating the next steps, which may include an appeal, said Thomas Lavelle, senior vice president and general counsel at Rambus.
Rambus has sued numerous companies that it claims violated its memory patents and chip technologies. Rambus has settled and signed license agreements with companies like Samsung, Nvidia and Mediatek, but other companies are fighting Rambus. Late last year a California jury rejected a $4 billion antitrust claim by Rambus against rivals Hynix Semiconductor and Micron Technology. The U.S. Patent and Trademark Office has also rejected many Rambus patents that were part of lawsuits.
Rambus' competitors have alleged that the company deceived members of memory standards-setting organization Joint Electron Device Engineering Council (JEDEC) by not disclosing its patents while working with the organization to create memory standards.