DDR2 memory is optimised for graphics

Elpida Memory has developed a range of 128Mbit (4M x 32bit) DDR2 SDRAM devices for notebook and desktop PC graphics applications.

Elpida Memory has developed a range of 128Mbit (4M x 32bit) DDR2 SDRAM devices for notebook and desktop PC graphics applications.

The new devices offer high speed, low power and enhanced thermal characteristics that enable them to perform in the constrained environments often experienced by mobile applications.

The devices incorporate "GDDR2-M" technology, featuring an innovative low-power termination scheme and a new data inversion technology that was jointly developed with ATI Technologies to speed operation and reduce power consumption.

The new x32 DDR2 SDRAM devices have been optimised for graphics applications using the "GDDR2-M" technology.

The design is based on the standard DDR2 SDRAM architecture, with enhanced on-die termination (ODT) and new data inversion technology.

Data inversion technology is a hardware design technique that was jointly developed by both Elpida Memory and ATI Technologies, and it has been incorporated into both the memory device and the visual processing unit (VPU) devices.

This technology alters the pattern of data that flows between the memory and VPU to minimise data flipping (switching).

Data flipping occurs during approximately fifty percent of all data transfers, and this is a common source of noise and power consumption of high-speed databuses.

The end result of incorporating this new data inversion technology is a wide, valid databus with 50% less noise and lower power versus devices that do not use this technology.

On-die termination (ODT) will be widely adopted in the conventional DDR2 SDRAM architecture, because it helps to create a clean signal during high-speed data transmissions.

Elpida's enhanced ODT used in GDDR2-M is different from that used in standard DDR2 SDRAM in that it is a 'pull-down' type self-termination that works effectively with the high-speed, point-to-point interface used in graphics.

This version of ODT minimises the direct current (DC) power at the termination circuit.

As a result, graphics systems can reduce the size of the board, and consequently the system cost.

This is an ideal implementation for mobile graphics systems where high-speed is necessary, but power and space are both very precious resources.

Elpida's new 128Mbit DDR2 SDRAM devices are organised as four banks of 1Mword x 32bit.

The three new devices (DC0122A-35, DC0122A-40, DC0122A-45) are available now in sample quantities in 350, 400 and 450MHz versions to match the performance of the latest VPUs, delivering high-bandwidth performance of 700, 800 or 900 Mbit/s, respectively.

Using Elpida's proven 0.13-micron process technology, the new devices offer low-voltage operation (VDDQ 1.8V, VDD 2.5V) as well as low memory power consumption (only 1.7W for the 350 and 400MHz versions) which is particularly important for notebook computers.

The new devices have burst read/write operation, a burst length (BL) of 4, and sequential burst sequences.

Data strobes (DQS) for both read and write are available, resulting in reliable, high-speed bus designs.

The devices operate with a fixed/CAS latency (CL) of 6.

They also have 4096 refresh cycles: 7.8 micros (4096 rows/32ms) and implement both auto refresh and self refresh.

The packaging is standard 144-ball FBGA.

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