Irvine, Calif. - Toshiba America Electronic Components Inc. is sampling a 1-gigabit multilevel cell (MLC) NAND electrically erasable programmable read-only memory (E2PROM). Production of the single-chip device is planned for the first quarter, by which time the company also expects a two-die stack that will provide 2 Gbits of storage in a single thin small-outline package (TSOP). Target applications for the memory device include digital cameras, cellular telephones and personal digital assistants as well as streaming audio/video equipment and other emerging markets for flash technology.
Paul Liu, Toshiba's manager of business development for flash memory, said the company has been marketing a 1-Gbit chip that consists of two stacked 512-Mbit, single-level cell (SLC) dice. The MLC design increases storage capacity by storing two bits of data in a cell instead of only one bit. It also lowers the cost per bit of storage by approximately 40 percent.
A downside of MLC is the need for additional circuitry to contend with four voltage levels per cell in the denser design, according to Liu. MLC also has less read bandwidth (6.7 Mbytes/second compared with 10 Mbytes/s), and takes longer to program (0.42 Mbytes/s compared with 2 Mbytes/s or more for SLC). Nevertheless, MLC is popular in consumer applications and adequate for most requirements.
In August Samsung Semiconductor Inc. (San Jose, Calif.) introduced a monolithic SLC flash memory device with a 1-Gbit capacity. "The major reason that flash manufacturers are leaning toward multilevel devices is the potential for lower costs," noted Erik Aldana, Samsung's product marketing manager for flash memory. Samsung's device is manufactured with 0.12-micron technology, whereas Toshiba uses 0.1-micron technology. Samsung is sampling the 1-Gbit monolithic flash device as well as a 2-Mbit SLC part.
Toshiba's memory device, the TC58010FT, was developed with help from Sunnyvale, Calif.-based SanDisk Corp. The chip will be manufactured at Toshiba's Yokkaichi, Japan, facility, and by the FlashVision joint venture established by Toshiba and SanDisk at Toshiba's Dominion Semiconductor manufacturing plant in Manassas, Va. Toshiba's device is organized as 128 Mbits x 8 bits. Its program time is 1 ms per 528-byte page and its erase time is 2 ms per 32k + 1,024 byte block. Its initial access time is 50 micro, and serial access is 50 nanoseconds. It comes in a 48-pin TSOP that measures 12 x 20 x 1.2 mm, and it is priced at $80 in sample quantities.
Samsung Semiconductor Inc.
EETInfo No. 614
Toshiba America Electronic
EETInfo No. 615