AUSTIN, Texas Samsung Electronics, the largest SRAM vendor, is expected to announce Monday (April 2) that it will join the QDR (quad-data-rate) group of vendors that now includes Cypress, IDT, Micron and NEC.
The decision is a blow to the SigmaRAM group, which has created a rival specification for high-performance SRAMs for networking markets. Members of the SigmaRAM group include GSI Technology, IBM, ISSI, Mitsubishi, Sony and Toshiba.
As part of its decision to join the QDR group, one knowledgeable source said that Samsung has agreed to drop its plan to develop a family of SigmaRAM parts that would support separate I/O for read and write functions. Samsung officials declined to comment.
Samsung is expected to continue to support the common I/O activities within the SigmaRAM group, but will not develop the important separate I/O part, both in single-data-rate and double-data-rate flavors. The separate I/O part is crucial to high-performance applications that seek to read and write data simultaneously, the target market of the QDR camp as well.
A press conference has been scheduled for Monday morning at Cypress Semiconductor's headquarters in San Jose, Calif. A Cypress spokesman said he could not publicly confirm which company would join the QDR group, beyond saying that it is "a very large Asian memory manufacturer."
Other sources, however, said Samsung's decision was made several weeks ago, after Korean-based executives decided to side with the QDR group. Their decision was based on perceptions that QDR was unlikely to be displaced by the SigmaRAM parts expected to come to market late this year.
Major design wins
Several of the QDR member companies have recently introduced 8-Mbit QDR parts that have achieved design wins at several major networking companies. Many of the QDR customers use SRAMs with single- and double-data-rate architectures, and are expected to stick with the same vendors.
Cypress, for example, recently introduced a family of 18-Mbit SRAMs that support the no-bus latency (NBL) architecture, which has been widely accepted in the networking industry. Moving from NBL designs to QDR is seen as a less difficult transition than the jump to the SigmaRAM parts.
Several companies in the SigmaRAM camp offer NBL SRAMs, but opted to take a fresh look at the very high-performance needs of the networking market.
The SigmaRAM specification was intended to support high-density, high-performance SRAMs. However, the package and pinout definitions supported by the QDR and SigmaRAM groups differ markedly, with the SigmaRAM group supporting a larger package that could accept 18-Mbit, 32-Mbit and larger densities. The QDR group supports a less aggressive package that is adequate for the 8/9-Mbit, and 16/18-Mbit densities. (The 18-Mbit part supports error correction).
The SigmaRAM group achieved standardization last year within the Jedec standards body. However, the QDR camp has gotten ahead in the market with the availability of QDR parts at the 8-Mbit density.