At this year's eMEX 2006, Winbond Electronics launched the Pseudo SRAM with the largest density in the market. The W968D6B has the following key features:
- W96 Series Pseudo SRAM
- Conforms to CellularRAM 1.5G standard
- Density: 256Mb (16M x 16)
- Low operating voltage and input/output voltage: 1.8V
- Frequency up to 133MHz
Pseudo SRAM Is Now Mainstream:
Rapid advances in mobile phone functionality, such as color photo browsing, JAVA game download and digital camera modules, have led to the need for more RAM buffer space in the handset memory. This increased demand in memory has made Pseudo SRAM an indispensable part of the data cache. In recent years, it has even completely replaced the traditional 6T SRAM in handsets. Pseudo SRAM's advantages include high capacity, low cost, high clock rates and lower power consumption. In many communication applications, the need today is for low power memory that costs less but provides more capacity. In the future Pseudo SRAM products will provide greater capacity and lower power consumption at even lower prices to meet this market demand.
Low Cost (Cost per Mb):
The Pseudo SRAM architecture is comprised of a DRAM macro core coupled with standard SRAM interface. DRAM macro core uses the traditional DRAM as its core where each memory cell is 1 Transistor + 1 Capacitor; the SRAM interface is designed specifically to be compatible with traditional SRAM. Pseudo SRAM includes an on-chip refresh circuit design that communicates with the outside world through the SRAM interface. This provides improved access speeds while minimizing design loading to take care refresh task. Pseudo SRAM manufactured using existing DRAM processes including those down to 110nm and 90nm. This has greatly reduced the cost of manufacturing Pseudo SRAM. The lower cost per Mb is now the main advantage of Pseudo SRAM.
Pseudo SRAM Offers the Following Features:
- Large memory capacity (16Mb ~ 256Mb)
- Higher frequency (133MHz)
- Smaller die size (1T Cell)
- Lower power consumption
- Compatible with DRAM production process
- On-chip refreshing circuit resolves the need to periodically recharge the capacitors in DRAM memory to keep data alive, reducing the design complexity for users.
There are currently three Pseudo SRAM standards in the market. Apart from the proprietary standard used by Samsung and the CSOMO standard used by Japanese vendors, the most popular standard on the market is the CellularRAM Alliance's CRAM 1.0G/1.5G/2.0G standard. Winbond's Pseudo SRAM product line cover both COSMO and CRAM, ensuring that our products can meet any requirements. (Winbond Electronics is currently a member of the CellularRAM Alliance)