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
