Three of Japan's major electronics manufacturers have agreed on a standard interface specification for a type of memory in third-generation (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 a statement.
Fujitsu, NEC Electronics and Toshiba have agreed on interface specifications for pseudo static random access memory (PSRAM) that will allow them to freely use each other's production of memory in mobile phones. NEC, Toshiba and Fujitsu make mobile phones for the Japanese domestic market, while NEC also makes mobile phones for overseas markets. The specification is called Common Specifications for Mobile RAM (COSMORAM) Rev. 3.
PSRAM is similar to static RAM (SRAM) memory, which acts as a buffer and a working memory. PSRAM's memory, which has a structure similar to dynamic RAM (DRAM) 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 spokesperson, Junichi Nagaki.
It usually found in multi-chip packages (MCPs) containing stacks of chips that need to be physically close together to work well, but can't 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 allowed for faster data transfer inside mobile phones and helped 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 agreement would 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.
It follows several agreements between the manufacturers to cooperate 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 produced chips with a capacity of 32MB to 128MB, he said.
Toshiba would not disclose its customers, Nagaki said.
Elpida Memory would produce 500,000 to 1 million 64MB units per month at its manufacturing facility in Hiroshima in western Japan, after April 1, 2005, NEC Electronics spokesperson, Sophie Yamamoto, said.
Elpida and NEC made a total of 500,000 to 1 million 32Mbit units of PSRAM at Elpida's Hiroshima factory and NEC Kyushu's facility, she said.
Fujitsu has its PSRAM parts produced in a foundry in capacities ranging from 32Mbits up to 128Mbits, company spokesperson, Kazuhiro Kikuchi, said.
The company did not disclose the name of the foundry.
The PSRAM wouldbe used in MCPs with NOR flash memory, but the company had not decided where it wouldl produce the latest version of the memory, Kikuchi said.