GENERAL DESCRIPTION

The W9725G8JB is a 256M bits DDR2 SDRAM, organized as 8,388,608 words x 4 banks x 8 bits. This device achieves high speed transfer rates up to 1066Mb/sec/pin (DDR2-1066) for general applications. W9725G8JB is sorted into the following speed grades: -18, -25, 25I and -3. The -18 is compliant to the DDR2-1066 (7-7-7) specification. The -25/25I are compliant to the DDR2-800 (5-5-5) or DDR2-800 (6-6-6) specification (the 25I industrial grade which is guaranteed to support -40°C ≤ TCASE ≤ 95°C). The -3 is compliant to the DDR2-667 (5-5-5) specification.

FEATURES

• Power Supply: VDD, VDDQ = 1.8 V ± 0.1 V

• Double Data Rate architecture: two data transfers per clock cycle

• CAS Latency: 3, 4, 5, 6 and 7

• Burst Length: 4 and 8

• Bi-directional, differential data strobes (DQS and DQS ) are transmitted / received with data

• Edge-aligned with Read data and center-aligned with Write data

• DLL aligns DQ and DQS transitions with clock

• Differential clock inputs (CLK and CLK )

• Data masks (DM) for write data.

• Commands entered on each positive CLK edge, data and data mask are referenced to both edges of DQS

• Posted CAS programmable additive latency supported to make command and data bus efficiency

• Read Latency = Additive Latency plus CAS Latency (RL = AL + CL)

• Off-Chip-Driver impedance adjustment (OCD) and On-Die-Termination (ODT) for better signal quality

• Auto-precharge operation for read and write bursts

• Auto Refresh and Self Refresh modes

• Precharged Power Down and Active Power Down

• Write Data Mask

• Write Latency = Read Latency - 1 (WL = RL - 1)

• Interface: SSTL_18

• Packaged in WBGA 60 Ball (8X12.5 mm2), using Lead free materials with RoHS compliant