Three of Japan's major electronics manufacturers have
agreed on a standard interface specification for a type of memory
in 3G mobile phones that will allow the companies to use a common
component design to help phones function better.
The companies will begin production of memory parts based on the
specification in March 2005, according to the statement.
Fujitsu, NEC Electronics and Toshiba have agreed on interface
specifications for PSRAM (pseudo static random access memory) that
will allow them to freely use each other's production of memory in
mobile phones.
NEC and Toshiba and Fujitsu make mobile phones for the Japanese
domestic market, while NEC also makes mobile phones for overseas
markets. The specification is called COSMORAM (Common
Specifications for Mobile RAM) Rev. 3.
PSRAM is similar to SRAM (static RAM) memory, which acts as a
buffer and a working memory. PSRAM's memory, which has a structure
similar to DRAM (dynamic RAM) memory, is easier to make in bigger
densities. PSRAM works faster and consumes less electricity than
other types of memory performing the same functions in mobile
devices, according to Toshiba spokesman Junichi Nagaki.
PSRAM is usually found in multi-chip packages (MCPs) containing
stacks of chips that need to be physically close together to work
well, but cannot be crammed efficiently or easily into a single
silicon chip. MCPs in mobile phones contain other types of memory,
for example NOR flash memory to store application code and NAND
flash memory for file memory.
PSRAM's higher speeds allow for faster data transfer inside
mobile phones and help makers more easily design
higher-functionality 3G phones, Nagaki said. The companies did not
say how the specification would improve data transfer speed or
phone design methods.
The announcement will help PSRAM memory makers to fit in higher
densities into the MCPs and allow them to act as alternative
sources for each other, the companies said.
The announcement follows several agreements between the
manufacturers to co-operate on memory standards technology for
mobile phones.
In September 1998, the companies agreed to promote common
specifications for MCPs, which included flash memory and SRAM. The
companies announced a series of common interface specifications for
PSRAM and stacked MCPs in March 2002, and PSRAM and stacked MCPs in
February 2003.
Toshiba produces PSRAM at the company's Yokkaichi manufacturing
plant in Mie prefecture, western Japan. The plant produces chips
with a capacity of 32Mbits to 128Mbits, he said. Toshiba will not
disclose its customers, Nagaki said.
Elpida Memory will produce 500,000 to one million 64Mbits
units a month at its manufacturing facility in Hiroshima in western
Japan, after 1 April 2005, said NEC Electronics spokeswoman Sophie
Yamamoto. Elpida and NEC make a total of 500,000 to one million
32Mbit units of PSRAM at Elpida's Hiroshima factory and NEC
Kyushu's facility in Kyushu, southern Japan, she said.
Fujitsu has its PSRAM parts produced in a foundry in capacities
ranging from 32Mbits up to 128Mbits, said Kazuhiro Kikuchi, a
company spokesman. The company did not disclose the name of the
foundry. The PSRAM will be used in MCPs with NOR flash memory, but
the company has not decided where it will produce the latest
version of the memory, Kikuchi said.
Paul Kallender writes for IDG News Service