The contents of the suits echo those Rambus filed in the late 1990s: in one suit, Rambus named Samsung as allegedly infringing on 11 patents involving SDRAM and DDR memory.
A separate suit alleges that Samsung had also infringed on 14 patents Rambus held in GDDR2 and GDDR3 memory, specifically used in graphics, as well as the more generic DDR-2 memory type. Both suits were filed Monday in the U.S. District Court for the Northern District of California. Samsung had previously licensed the relevant memory patents from Rambus, although the agreement was scheduled to expire at the end of the month.
Samsung officials declined to comment.
According to Rambus executives, Samsungs patent license was set to expire as unrelated patent infringement suits against Hynix Semiconductor and Infineon Technologies are preparing to resume, following favorable rulings by U.S. courts. At the same time, according to Rambus vice president and general counsel John Danforth, Rambus noticed that Samsung was breaching its contract with unspecified violations.
Under the terms of its original license, Samsung had paid a 3.5 percent per-unit royalty to Rambus on sales of DDR memory. Following a district court ruling in May 2001 that tossed all all but three of the companys patent claims against Infineon, however, Samsung negotiated a reduced rate via an amendment to the contract. That amendment lowered the companys total royalty payments to less than $3 million per quarter, or less than 10 percent of the companys quarterly revenues, Danforth said.