Hitachi, Toshiba Sample 512-Mbit Flash Devices
(10/10/00, 8:36 p.m. ET) By Anthony Cataldo, EE Times
Hitachi Ltd. and Toshiba Corp. have each introduced 512-Mbit flash devices, with twice the density of their respective highest-density flash devices.
The 512-Mbit milestone was made possible by moves to smaller process geometries and advanced storage cell techniques. The parts are intended for use in flash storage cards.
Toshiba's NAND-type memory uses a 0.16-micron process technology jointly developed with U.S. partner SanDisk.
Hitachi (stock: HIT), meanwhile, leveraged its 0.18-micron process technology together with a multilevel-cell storage technology.
To extend the capacity potential even further, both companies are using multichip packages so that two 512-Mbit die can be stacked in one TSOP. That scheme enables small-form-factor flash cards with up to 128 Mbytes.
A flash card at that density can, for example, store two hours of compressed music, according to Hitachi.
Toshiba plans to use the devices as the basis for 64-Mbyte and 128-Mbyte SmartMedia and SD flash cards. Hitachi, meanwhile, will incorporate its devices into a 128-Mbyte MultiMediaCard.
Hitachi will also mount 16 of its stacked 1-Gbit devices into one PC-ATA card for 2 Gbytes of capacity.
Jointly designed with Mitsubishi Electric Corp., Hitachi's 512-Mbit AND-type flash chip can store 2 bits of data for every memory cell, a voltage-splitting technique known as multilevel-cell storage (MLC).
Hitachi started using MLC several years ago with its 256-Mbit-generation device. Though several flash vendors use this method of squeezing in more bits per cell, it has been adopted sparingly because of reliability concerns and the complexity involved in dividing the voltage into discrete levels that correspond with different data values.
Hitachi's 512-Mbit device is sampling in Japan for about $129, while the 1-Gbit stacked device lists at about $257. Both come in a 48-pin TSOP type-I package.
Toshiba's samples are also priced at $129 for the 512-Mbit part and $257 for the 1-Gbit.
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