NEC Corp. said Thursday it has developed a new memory chip designed for use in portable devices such as cellular telephones and personal digital assistants (PDAs). In such devices power consumption and physical size are key factors and the new chip scores highly in both categories, said NEC.
At present, cellular telephone or portable device manufacturers generally have a choice between SDRAM ( synchronous dynamic random access memory) or SRAM (static random access memory) chips. For a similar size chip, the SDRAM holds more data but this comes at the expense of greater power consumption.
NEC's new Mobile RAM has a capacity of 16M bits which is equal to that of SDRAM chips currently used in portable devices but consumes 100 microamps in standby mode. In contrast, a comparable SDRAM chip produced by NEC consumes 170 microamps. An SRAM chip consumes less power, around 15 microamps, but can hold only half the amount of data, 8M bits, in a comparable size package.
The Mobile RAM also features a power-down mode at which power consumption is just 10 microamps. Similar to a notebook computer's sleep mode, the power-down mode is not offered on comparable SRAM and SDRAM chips.
"This is really aimed at third-generation cellular handsets," said Aston Bridgman, a spokesman for NEC. "They are expected to be much more complex and have many more functions than existing handsets so power consumption will probably be a lot higher and manufacturers are likely to want to include a power down mode."The biggest competitor to the new chip is the FCRAM (fast cycle random access memory) chip pioneered by Fujitsu Ltd. It has the capability to operate in power-down mode and NEC's new device largely equals FCRAM for power consumption in standby and power-down mode.
NEC expects to begin shipping samples of the chips from October before beginning full commercial production at the rate of 1 million chips per month from March 2001. In the future it hopes to produce versions of the memory in 32, 64 and 128M bit sizes although development on these chips is not yet complete.
NEC, in Tokyo, can be found online at http://www.nec.co.jp/.