Preliminary
GS8662T20/38AE-450/400/375/333/300
450 MHz–300 MHz
165-Bump BGA
Commercial Temp
Industrial Temp
72Mb SigmaCIO DDR-II+
Burst of 2 SRAM
1.8 V V
DD
1.8 V and 1.5 V I/O
Features
• 2.5 Clock Latency
• Simultaneous Read and Write SigmaCIO™ Interface
• Common I/O bus
• JEDEC-standard pinout and package
• Double Data Rate interface
• Byte Write (x36 and x18) and Nybble Write (x8) function
• Burst of 2 Read and Write
• 1.8 V +100/–100 mV core power supply
• 1.5 V or 1.8 V HSTL Interface
• Pipelined read operation with self-timed Late Write
• Fully coherent read and write pipelines
• ZQ pin for programmable output drive strength
• IEEE 1149.1 JTAG-compliant Boundary Scan
• Pin-compatible with present 9Mb, 18Mb, 36Mb and future
144Mb devices
Bottom View
165-Bump, 15 mm x 17 mm BGA
• 165-bump, 15 mm x 17 mm, 1 mm bump pitch BGA package
• RoHS-compliant 165-bump BGA package available
1 mm Bump Pitch, 11 x 15 Bump Array
SigmaCIO™ Family Overview
Clocking and Addressing Schemes
The GS8662T20/38AE are built in compliance with the
SigmaCIO DDR-II+ SRAM pinout standard for Common I/O
synchronous SRAMs. They are 75,497,472-bit (72Mb)
SRAMs. The GS8662T20/38AE SigmaCIO SRAMs are just
one element in a family of low power, low voltage HSTL I/O
SRAMs designed to operate at the speeds needed to implement
economical high performance networking systems.
The GS8662T20/38AE SigmaCIO DDR-II+ SRAMs are
synchronous devices. They employ two input register clock
inputs, K and K. K and K are independent single-ended clock
inputs, not differential inputs to a single differential clock input
buffer.
Common I/O x36 and x18 SigmaCIO DDR-II+ B2RAMs
always transfer data in two packets. When a new address is
loaded, A0 presets an internal 1 bit address counter. The
counter increments by 1 (toggles) for each beat of a burst of
two data transfer.
Common I/O x8 SigmaCIO DDR-II+ B2 RAMs always
transfer data in two packets. When a new address is loaded,
the LSB is internally set to 0 for the first read or write transfer,
and incremented by 1 for the next transfer. Because the LSB
is tied off internally, the address field of a x8 SigmaCIO DDR-
II+ B4 RAM is always one address pin less than the advertised
index depth (e.g., the 4M x 18 has a 2048K addressable index).
Parameter Synopsis
-450
-400
-375
-333
3.3 ns
0.45 ns
-300
3.0 ns
0.45 ns
tKHKH
tKHQV
2.22 ns
0.45 ns
2.5 ns
2.67 ns
0.45 ns
0.45 ns
Rev: 1.00b 10/2009
1/31
© 2008, GSI Technology
Specifications cited are subject to change without notice. For latest documentation see http://www.gsitechnology.com.