• NBT (No Bus Turn Around) functionality allows zero wait
Read-Write-Read bus utilization; fully pin-compatible with
both pipelined and flow through NtRAM™, NoBL™ and
ZBT™ SRAMs
• 2.5 V or 3.3 V +10%/–10% core power supply
• 2.5 V or 3.3 V I/O supply
• User-configurable Pipeline and Flow Through mode
• ZQ mode pin for user-selectable high
• IEEE 1149.1 JTAG-compatible Boundary Scan
• On-chip write parity checking; even or odd selectable
• On-chip parity encoding and error detection
• LBO
pin for Linear or Interleave Burst mode
• Pin-compatible with 2M, 4M, and 8M devices
• Byte write operation (9-bit Bytes)
• 3 chip enable signals for easy depth expansion
• ZZ Pin for automatic power-down
• JEDEC-standard 119-, 165-, or 209-Bump BGA package
/low output drive
250 MHz–133 MHz
2.5 V or 3.3 V V
DD
2.5 V or 3.3 V I/O
read/write control inputs are captured on the rising edge of the
input clock. Burst order control (LBO
rail for proper operation. Asynchronous inputs include the
Sleep mode enable (ZZ) and Output Enable. Output Enable can
be used to override the synchronous control of the output
drivers and turn the RAM's output drivers off at any time.
Write cycles are internally self-timed and initiated by the rising
edge of the clock input. This feature eliminates complex offchip write pulse generation required by asynchronous SRAMs
and simplifies input signal timing.
The GS8162Z18(B/D)/36(B/D)/72(C) may be configured by
the user to operate in Pipeline or Flow Through mode.
Operating as a pipelined synchronous device, in addition to the
rising-edge-triggered registers that capture input signals, the
device incorporates a rising edge triggered output register. For
read cycles, pipelined SRAM output data is temporarily stored
by the edge-triggered output register during the access cycle
and then released to the output drivers at the next rising edge of
clock.
) must be tied to a power
-250 -225 -200 -166 -150 -133 Unit
Pipeline
3-1-1-1
3.3 V
2.5 V
Flow
Through
2-1-1-1
3.3 V
2.5 V
t
KQ
tCycle
Curr (x18)
Curr (x36)
Curr (x72)
Curr (x18)
Curr (x36)
Curr (x72)
t
KQ
tCycle
Curr (x18)
Curr (x36)
Curr (x72)
Curr (x18)
Curr (x36)
Curr (x72)
2.5
4.0
280
330
n/a
275
320
n/a
5.5
5.5
175
200
n/a
175
200
n/a
2.7
4.4
255
300
n/a
250
295
n/a
6.0
6.0
165
190
n/a
165
190
n/a
3.0
5.0
230
270
350
230
265
335
6.5
6.5
160
180
225
160
180
225
3.4
6.0
200
230
300
195
225
290
7.0
7.0
150
170
115
150
170
115
3.8
6.7
185
215
270
180
210
260
7.5
7.5
145
165
210
145
165
210
4.0
7.5nsns
165
mA
190
mA
245
mA
165
mA
185
mA
235
mA
8.5
8.5nsns
135
mA
150
mA
185
mA
135
mA
150
mA
185
mA
Functional Description
The GS8162Z18(B/D)/36(B/D)/72(C) is an 18Mbit
Synchronous Static SRAM. GSI's NBT SRAMs, like ZBT,
NtRAM, NoBL or other pipelined read/double late write or
flow through read/single late write SRAMs, allow utilization
of all available bus bandwidth by eliminating the need to insert
deselect cycles when the device is switched from read to write
cycles.
The GS8162Z18(B/D)/36(B/D)/72(C) is implemented with
GSI's high performance CMOS technology and is available in
a JEDEC-standard 119-bump (x18 & x36), 165-bump (x18 &
x36), or 209-bump (x72) BGA package.
Because it is a synchronous device, address, data inputs, and
Specifications cited are subject to change without notice. For latest documentation see http://www.gsitechnology.com.
NoBL is a trademark of Cypress Semiconductor Corp.. NtRAM is a trademark of Samsung Electronics Co.. ZBT is a trademark of Integrated Device Technology, Inc.
Specifications cited are subject to change without notice. For latest documentation see http://www.gsitechnology.com.
GS8162Z18(B/D)/GS8162Z36(B/D)/GS8162Z72(C)
Functional Details
Clocking
Deassertion of the Clock Enable (CKE) input blocks the Clock input from reaching the RAM's internal circuits. It may be used to
suspend RAM operations. Failure to observe Clock Enable set-up or hold requirements will result in erratic operation.
Pipeline Mode Read and Write Operations
All inputs (with the exception of Output Enable, Linear Burst Order and Sleep) are synchronized to rising clock edges. Single cycle
read and write operations must be initiated with the Advance/Load
activation is accomplished by asserting all three of the Chip Enable inputs (E
inputs will deactivate the device.
pin (ADV) held low, in order to load the new address. Device
, E2, and E3). Deassertion of any one of the Enable
1
FunctionW
B
B
A
B
B
B
C
D
ReadHXXXX
Write Byte “a”LLHHH
Write Byte “b”LHLHH
Write Byte “c”LHHLH
Write Byte “d”LHHHL
Write all BytesLLLLL
Write Abort/NOPLHHHH
Read operation is initiated when the following conditions are satisfied at the rising edge of clock: CKE
chip enables (E
1
, E2, and E3) are active, the write enable input signals W is deasserted high, and ADV is asserted low. The address
is asserted low, all three
presented to the address inputs is latched into the address register and presented to the memory core and control logic. The control
logic determines that a read access is in progress and allows the requested data to propagate to the input of the output register. At
the next rising edge of clock the read data is allowed to propagate through the output register and onto the output pins.
Write operation occurs when the RAM is selected, CKE is active, and the Write input is sampled low at the rising edge of clock.
The Byte Write Enable inputs (B
, BB, BC, and BD) determine which bytes will be written. All or none may be activated. A write
A
cycle with no Byte Write inputs active is a no-op cycle. The pipelined NBT SRAM provides double late write functionality,
matching the write command versus data pipeline length (2 cycles) to the read command versus data pipeline length (2 cycles). At
the first rising edge of clock, Enable, Write, Byte Write(s), and Address are registered. The Data In associated with that address is
required at the third rising edge of clock.
Flow Through Mode Read and Write Operations
Operation of the RAM in Flow Through mode is very similar to operations in Pipeline mode. Activation of a Read Cycle and the
use of the Burst Address Counter is identical. In Flow Through mode the device may begin driving out new data immediately after
new address are clocked into the RAM, rather than holding new data until the following (second) clock edge. Therefore, in Flow
Through mode the read pipeline is one cycle shorter than in Pipeline mode.
Write operations are initiated in the same way, but differ in that the write pipeline is one cycle shorter as well, preserving the ability
to turn the bus from reads to writes without inserting any dead cycles. While the pipelined NBT RAMs implement a double late
write protocol in Flow Through mode a single late write protocol mode is observed. Therefore, in Flow Through mode, address
and control are registered on the first rising edge of clock and data in is required at the data input pins at the second rising edge of
clock.
1.Continue Burst cycles, whether Read or Write, use the same control inputs. A Deselect continue cycle can only be entered into if a
Deselect cycle is executed first.
2.Dummy Read and Write abort can be considered NOPs because the SRAM performs no operation. A Write abort occurs when the W
is sampled low but no Byte Write pins are active, so no write operation is performed.
3.G
can be wired low to minimize the number of control signals provided to the SRAM. Output drivers will automatically turn off during write
cycles.
4.If CKE
5. X = Don’t Care; H = Logic High; L = Logic Low; Bx
6.All inputs, except G
7.Wait states can be inserted by setting CKE
8.This device contains circuitry that ensures all outputs are in High Z during power-up.
9.A 2-bit burst counter is incorporated.
10. The address counter is incriminated for all Burst continue cycles.
High occurs during a pipelined read cycle, the DQ bus will remain active (Low Z). If CKE High occurs during a write cycle, the bus
will remain in High Z.
= High = All Byte Write signals are high; Bx = Low = One or more Byte/Write signals
are Low
and ZZ must meet setup and hold times of rising clock edge.