GS8662T08/09/18/36E-250/200/167
165-Bump BGA
Commercial Temp
Industrial Temp
Features
• Simultaneous Read and Write SigmaDDR-II™ 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 144Mb
devices
• 165-bump, 15 mm x 17 mm, 1 mm bump pitch BGA package
• RoHS-compliant 165-bump BGA package available
72Mb SigmaDDR-II™
Burst of 2 SRAM
250 MHz–167 MHz
1.8 V V
DD
1.8 V and 1.5 V I/O
Clocking and Addressing Schemes
The GS8662T08/09/18/36E SigmaDDR-II SRAMs are
synchronous devices. They employ two input register clock
inputs, K and K. K and K are independent single-ended clock
Rev: 1.10 8/2012
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The GS8662T08/09/18/36E are built in compliance with the
SigmaDDR-II SRAM pinout standard for Common I/O
synchronous SRAMs. They are 75,497,472-bit (72Mb)
SRAMs. The GS8662T08/09/18/36E SigmaDDR-II 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.
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SigmaDDR-II™ Family Overview
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inputs, not differential inputs to a single differential clock input
buffer. The device also allows the user to manipulate the
output register clock inputs quasi independently with the C and
C clock inputs. C and C are also independent single-ended
clock inputs, not differential inputs. If the C clocks are tied
high, the K clocks are routed internally to fire the output
registers instead.
Each internal read and write operation in a SigmaDDR-II B2
RAM is two times wider than the device I/O bus. An input data
bus de-multiplexer is used to accumulate incoming data before
it is simultaneously written to the memory array. An output
data multiplexer is used to capture the data produced from a
single memory array read and then route it to the appropriate
output drivers as needed.
When a new address is loaded into a x18 or x36 version of the
part, A0 is used to initialize the pointers that control the data
multiplexer / de-multiplexer so the RAM can perform "critical
word first" operations. From an external address point of view,
regardless of the starting point, the data transfers always follow
the same sequence {0, 1} or {1, 0} (where the digits shown
represent A0).
Unlike the x18 and x36 versions, the input and output data
multiplexers of the x8 and x9 versions are not preset by
address inputs and therefore do not allow "critical word first"
operations. The address fields of the x8 and x9 SigmaDDR-II
B2 RAMs are one address pin less than the advertised index
depth (e.g., the 8M x 8 has an 4M addressable index, and A0 is
not an accessible address pin).
Specifications cited are subject to change without notice. For latest documentation see http://www.gsitechnology.com.
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