Austin, Texas -- Micron Technology Inc. (Boise, Idaho) has developed a family of multichip-packaged memories that combine a low-power DRAM with a NAND flash from IMFlash Technology Inc., Micron's joint venture with Intel Corp. The packages target smart phones.

Silicon Storage Technology Inc. (Sunnyvale, Calif.), meanwhile, is targeting voice phones, which continue to sell well in developing countries, with multichip packages (MCPs) that house a 32-Mbit SST flash with 4-, 8- or 16-Mbit pseudo-SRAM.

While much of the cellular-handset industry continues to store code in NOR flash, a growing portion of the data-intensive handset market is using NAND to store both code and data. Code is uploaded to DRAM during bootup.

"We believe the majority of feature-rich phones will become NAND-centric," said Micron MCP marketing manager Gavin Hagen.

The initial Micron multichip package uses a 1-Gbit NAND in a 72-nanometer process. Micron's road map includes a 2-Gbit-density part later this year. The low-power DRAM is 512 Mbits.

Micron has developed a low-power DRAM technology, Endur-IC, that uses a two-transistor/one-capacitor architecture. The approach offers mobile users higher reliability than the traditional 1T/1C architecture, said Achim Hill, senior director of marketing for Micron's mobile memory group.

The current MCPs on the market that contain NAND devices are divided in approach between the ball layout championed by Samsung Electronics and the ball array established by Toshiba Corp. Micron's MCPs are Toshiba-compatible.

The Micron MCPs are available now for evaluation and will be on display at the 3GSM World Congress, planned for Feb. 13-16 in Barcelona, Spain. Full production is expected to begin in the fourth quarter.

The Silicon Storage Technology devices for conventional voice phones, meanwhile, include a dual-bank design that improves erase performance by allowing one bank to read or write while the other bank is being erased or programmed, said Paul Liu, vice president of the special-products group.

According to Web-Feet Research (Monterey, Calif.), the voice-only handset market is expected to retain about 30 percent of the world market in units, with a value of $7 billion. In China, India and other emerging markets, voice-only models continue to represent the majority of phones, presenting SST with a growing market.