The race to find the next big thing in memory technology has another twist on its path. Mobile phones often use static RAM (SRAM) because of its useful low power requirements; it doesn't need constant refreshing like DRAM. Now Cypress, Infineon and Micron have started sampling CellularRAM, a pseudo SRAM (PSRAM).

SRAM is expensive because it normally uses 6 transistors for every bit of memory. That makes it effectively 6 times the price of DRAM. But the latter's constant need to be refreshed means that it is power hungry and that's the last thing you want in a battery operated device when you're looking for long stand-by times.

PSRAM isn't quite SRAM but it's close enough. It uses a transistor and a capacitor per bit of memory and can do its own refreshing. But that means no extra refresh circuitry to chew your battery, as long as the PSRAM has power, it stays refreshed.

The fact that PSRAM is so much simpler than SRAM to produce and takes up much less silicon should lead to it being much cheaper eventually.

----
Full Article
The Inquirer