IS61NSCS25672 Datasheet, PDF (6/32 Pages) Integrated Silicon Solution, Inc – RAM 256K x 72, 512K x 36 18Mb Synchronous SRAM

IS61NSCS25672
IS61NSCS51236
ISSI ^®
BACKGROUND
The central characteristics of the ISSI ΣRAMs are that
they are extremely fast and consume very little power.
Because both operating and interface power is low,
ΣRAMs can be implemented in a wide (x72) configuration,
providing very high single package bandwidth (in excess
of 20 Gb/s in ordinary pipelined configuration) and very low
random access latency (5 ns). The use of very low voltage
circuits in the core and 1.8V or 1.5V interface voltages allow
the speed, power and density performance of ΣRAMs.
Although the SigmaRAM family pinouts have been designed
to support a number of different common read and write
protocol options, not all SigmaRAM implementations will
support all possible protocols. The following timing diagrams
provide a quick comparison between read and write
protocols options available in the context of the SigmaRAM
standard. This data sheet covers the single data rate (non-
DDR), Double Late Write, Pipelined Read SigmaRAM.
The character of the applications for fast synchronous
SRAMs in networking systems are extremely diverse.
ΣRAMs have been developed to address the diverse
needs of the networking market in a manner that can be
supported with a unified development and manufacturing
infrastructure. ΣRAMs address each of the bus protocol
options commonly found in networking systems. This
allows the ΣRAM to find application in radical shrinks and
speed-ups of existing networking chip sets that were
designed for use with older SRAMs, like the NBT or Nt,
Late Write, or Double Data Rate SRAMs, as well as with
new chip sets and ASIC’s that employ the Echo Clocks
and realize the full potential of the ΣRAMs.
COMMON I/O SigmaRAM FAMILY MODE COMPARISON—LATE WRITE VS. DOUBLE LATE WRITE
Double Late Write—Pipelined Read (Σ1x1Dp). For reference only.
CK
Address A
Control R
DQ
CQ
B
C
W
R
QA
D
E
W
R
DB
QC
F
W
DD
QE
Late Write—Pipelined Read (Σ1x1Lp). For reference only.
CK
Address A
Control R
DQ
CQ
B
C
D
E
F
X
W
R
X
W
QA
DC
QD
DF
6
Integrated Silicon Solution, Inc. — 1-800-379-4774
ADVANCE INFORMATION Rev. 00A
06/19/01