Fujitsu, NEC and Toshiba Agree on Common Specifications for Burst Mode Pseudo SRAM User Interface


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Tokyo -- Fujitsu Ltd., NEC Electronics Corp. and Toshiba Corp. have reached an agreement on common specifications for Pseudo Static Random Access Memory (PSRAM*1) devices that feature burst mode function enabling fast access operation.

Each of the three companies will independently manufacture and market PSRAM products based on the common specifications, which are to be called Common Specifications for Mobile RAM (COSMORAM), with product introduction expected to begin in the first half of fiscal 2003.

In September 1998, the three firms promulgated common specifications for stacked multi-chip packages (MCPs) that include both flash memory and SRAM. Then in March 2002, it was announced that the three companies agreed on common specifications for PSRAMs that feature page mode function, forming the basis for a common spec for the page mode PSRAM and stacked MCPs that include the PSRAM. Defining user-interface specifications for high-speed, high-density PSRAMs resolved compatibility problems, thereby allowing customers to efficiently implement the PSRAM devices of all three firms.

The trio of companies has now expanded the agreement to include common specifications for a burst mode PSRAM user interface and the stacked MCPs that house the PSRAMs. Burst mode function enables high-performance operation superior to fast page mode, targeting it to respond to the high-speed processing needs of next-generation cell phones and other mobile equipment, such as PDAs.

Because the specifications for burst mode PSRAM, much like those adopted for page mode PSRAM, standardize the basic electrical properties, packaging and pin layout, customers will benefit from a uniform design format, eliminating the need to customize designs for each product. This advantage will help shorten the design cycle and dramatically improve design efficiency. In addition, since the three companies are using common specs, they can also act as alternative sources for each other, helping to ensure a stable market supply.

The COSMORAM specifications for burst mode PSRAM user interface cover:

  • Densities
  • Supply voltage range
  • Control pin names
  • Truth table(*2)
  • Partial refresh(*3) function (refresh size and corresponding base address assignment)
  • Burst mode function (burst length[*4] and corresponding addressing)
  • Mode register(*5) defaults
  • Mode-register setting method
  • Power-on sequence(*6)
  • Pinouts
  • Packaging

Fujitsu Ltd. is a leading provider of customer-focused IT and communications solutions for the global marketplace.

Toshiba Corp. is a leader in information and communications systems, electronic components, consumer products, and power systems.

NEC Electronics Corp. is a wholly owned subsidiary of NEC Corp., one of the world's leading providers of Internet, broadband network and enterprise business solutions.

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