Double-data-rate clocking at heart of high-performance lines -- Toshiba powers up 256-Mbit DRAM
Jul. 21, 2000 (Electronic Engineering Times - CMP via COMTEX) -- TOKYO - Toshiba
Corp. is preparing a shift to 256-Mbit DRAM technology with a trio of product
families that use the double-data-rate clocking method. The new DRAMs will
coincide with Toshiba's move to 0.175-micron CMOS process technology.
The product offering reflects the company's strategy of making an early start on
high-performance, high-density DRAMs while minimizing production of DRAMs that
are also being made by its competitors. Currently the company produces 9.5
million 128-Mbit synchronous DRAM (SDRAM) and Rambus DRAM (RDRAM) devices a
month, while 64-Mbit production is being held at 1 million per month.
Overall, Toshiba intends to keep its DRAM production volume stable, increasing
slightly from about 22 million 64-Mbit equivalent units today to about 23
million by the end of the year, when the new products and process technology
come on stream.
The new 256-Mbit lineup includes double-data-rate (DDR) SDRAMs, fast-cycle DRAMs
(FCRAMs) and RDRAMs. Each supports the double-data-rate transfer mode in which
data is transferred on both the rising and falling edges of the clock cycle.
Some consider DDR SDRAM to be the next step after standard SDRAM because it is
based on similar core and interface technology. Toshiba is sampling nine types
of DDR SDRAMs, varying by configuration, clock speed, data transfer speed and
latency. Data transfer rates range from 286 Mbits/second (143 MHz) to 200
Mbits/s (125 MHz), while column-address strobe (CAS) latency is either 2 or 2.5.
Toshiba's RDRAMs, which are backed by Intel as the next-generation PC main
memory, will be offered in 800-, 711- and 600-MHz speed grades. The RDRAMs are
available in both by-16 and by-18 configurations, with error correction.
Toshiba's 256-Mbit-generation RDRAMs must still be submitted to Intel for
evaluation and validation, a spokesman said.
Toshiba's FCRAMs will be offered in data-mask and variable-write
function types.
Sample prices are $120 for the DDR SDRAMs, $150 for the RDRAMs and $200 for the
FCRAMs. Toshiba said it is still too early to determine production-quantity
prices. Volume production is scheduled to begin in December. |
