US-based high-speed interface technology licensing firm Rambus has agreed in principle to terms for a compulsory license with South Korea-based Hynix Semiconductor for SDR SDRAM and DDR SDRAM memory products.

According to Rambus, the parties have agreed to royalty rates of 1% for SDR SDRAM and 4.25% for DDR SDRAM memory devices for net sales after January 31, 2009 and before April 18, 2010. The latter rate applies to DDR, DDR2, DDR3, GDDR, GDDR2 and GDDR3 SDRAM devices, as well as DDR SGRAM devices.

Rambus has said that in addition, a proposed final judgment of $349m in damages, plus pre-judgment interest of approximately $48m has been submitted to the US District Court for the Northern District of California.

The final amount of pre-judgment interest depends on the date final judgment is entered. Damages and royalty rates are limited to US infringements. This case was originally filed by Hynix against Rambus in August 2000.

Thomas Lavelle, senior vice president and general counsel at Rambus, said: While the court still needs to resolve some outstanding issues, we are pleased to have reached agreement with Hynix on a number of terms. Our goal as always is to seek fair compensation for the use of our patented inventions, and this agreement will be a significant milestone in pursuit of that goal.