Rambus is suing Freescale, STMicroelectronics, Broadcom, LSI, MediaTek, and Nvidia both in the California courts and with the US ITC.
Rambus has also named HP, Hitachi, Motorola and Asustek as companies which are using the products which are the subject of the complaint.
"We have been attempting to license these companies for some time to no avail. One of the respondents frankly told us that the only way they would get serious is if we sued them. Others pursued a strategy of delay rather than negotiate a reasonable resolution," says Harold Hughes, CEO of Rambus.
The actions relate to two groups of patents which Rambus calls the Dally group and the Barth group of patents.
The Dally patents include products that incorporate PCI Express, certain Serial ATA, certain Serial Attached SCSI (SAS), and DisplayPort interfaces.
The Barth patents cover products that incorporate DDR, DDR2, DDR3, mobile DDR, LPDDR, LPDDR2, and GDDR3 memory controllers.
Accused semiconductor products in the complaint include graphics processors, media processors, communications processors, chip sets and other logic integrated circuits (ICs).
Rambus seems to have been encouraged in the new action by a successful ruling on the Barth group of patents by the ITC in a case involving Nvidia.
"The action against Nvidia was the first ever we have taken against a non-DRAM company," says Sharon Holt, v-p and general manager of Rambus’ semiconductor business group, "we had hoped by pursuing this action, other companies using our innovations and memory controllers on their chips would recognize our resolve to protect our patented innovations and further, would recognize the validity of our position given the ITC's decision in our favour. Yet rather than licensing the patents they were using, many chose instead to play the delay game."