DRAM-o-Rama 2004: Speed, Density Advances Kickstart The New Year

Look for faster memories with greater capacity this year, thanks to advances from Toshiba Corp., Rambus Inc., and Elpida Memory Inc.

First samples of a 512-Mbit high-performance DRAM sporting the new extreme-data-rate (XDR) interface are now available from Toshiba. The DRAMs also feature a 3.2-GHz data-transfer rate—the fastest of any memory device yet released. The XDR interface, developed by Rambus Inc. (www.rambus.com), allows eight data bits to transfer on every clock cycle. It thus delivers eight times the bandwidth of today's best-in-class PC memory.

Three versions of the new XDR DRAM are available: the TC59YM916AMG32A, '32B, and '32C. Each runs from a 1.8-V supply. Also, they're organized as 4 Mwords by 8 banks by 16 bits. The '32A has a 40-ns cycle time and a 27-ns latency. The '32B features a 50-ns cycle time and 35-ns latency. And, the '32C has a 60-ns cycle time and 35-ns latency.

Meanwhile, limited production quantities of a 1-Gbit double-data-rate SDRAM are coming via Elpida Memory Inc. The chips are also used on a 2-Gbyte registered DDR2 dual inline-memory module (DIMM) so customers can rapidly evaluate the new devices for use in next-generation server platforms. Additionally, Elpida is developing 4-Gbyte registered DIMMs and 2-Gbyte small-outline DIMMs based on the new 1-Gbit device.

The EDE1104AASE and EDE1108AASE versions of the DRAM are organized as 256 Mwords by 4 bits (8 banks) and 128 Mwords by 8 bits (8 banks), respectively. Operating from a 1.8-V supply, they come in 68-ball FBGA packages and transfer data at up to 533 Mbits/s. They also have a CAS latency of 3, 4, or 5 and a burst length of 4 or 8. Both offer off-chip driver impedance adjustment and on-die termination for improved signal quality.