GS88237AB-250/225/200/166/150/133
119-Bump BGA
Commercial Temp
Industrial Temp
Features
256K x 36
9Mb Synchronous Burst SRAMs
250 MHz–133 MHz
2.5 V or 3.3 V V
DD
2.5 V or 3.3 V I/O
• Single/Dual Cycle Deselect selectable
• IEEE 1149.1 JTAG-compatible Boundary Scan
• ZQ mode pin for user-selectable high/low output drive
• 2.5 V or 3.3 V +10%/–10% core power supply
• 2.5 V or 3.3 V I/O supply
• LBO pin for Linear or Interleaved Burst mode
• Internal input resistors on mode pins allow floating mode pins
• Byte Write (BW) and/or Global Write (GW) operation
• Internal self-timed write cycle
• Automatic power-down for portable applications
• JEDEC-standard 119-bump BGA package
SCD and DCD Pipelined Reads
The GS88237AB is a SCD (Single Cycle Deselect) and DCD
(Dual Cycle Deselect) pipelined synchronous SRAM. DCD
SRAMs pipeline disable commands to the same degree as read
commands. SCD SRAMs pipeline deselect commands one stage
less than read commands. SCD RAMs begin turning off their
outputs immediately after the deselect command has been
captured in the input registers. DCD RAMs hold the deselect
command for one full cycle and then begin turning off their
outputs just after the second rising edge of clock. The user may
configure this SRAM for either mode of operation using the SCD
mode input.
Byte Write and Global Write
Byte write operation is performed by using Byte Write enable
(BW) input combined with one or more individual byte write
signals (Bx). In addition, Global Write (GW) is available for
writing all bytes at one time, regardless of the Byte Write control
inputs.
FLXDrive™
The ZQ pin allows selection between high drive strength (ZQ low)
for multi-drop bus applications and normal drive strength (ZQ
floating or high) point-to-point applications. See the Output Driver
Characteristics chart for details.
Sleep Mode
Low power (Sleep mode) is attained through the assertion (High)
of the ZZ signal, or by stopping the clock (CK). Memory data is
retained during Sleep mode.
Core and Interface Voltages
The GS88237AB operates on a 2.5 V or 3.3 V power supply. All
input are 3.3 V and 2.5 V compatible. Separate output power
(V
DDQ
) pins are used to decouple output noise from the internal
circuits and are 3.3 V and 2.5 V compatible.
Functional Description
Applications
The GS88237AB is a 9,437,184-bit high performance
synchronous SRAM with a 2-bit burst address counter. Although
of a type originally developed for Level 2 Cache applications
supporting high performance CPUs, the device now finds
application in synchronous SRAM applications, ranging from
DSP main store to networking chip set support.
Controls
Addresses, data I/Os, chip enable (E1), address burst control
inputs (ADSP, ADSC, ADV), and write control inputs (Bx, BW,
GW) are synchronous and are controlled by a positive-edge-
triggered clock input (CK). Output enable (G) and power down
control (ZZ) are asynchronous inputs. Burst cycles can be initiated
with either ADSP or ADSC inputs. In Burst mode, subsequent
burst addresses are generated internally and are controlled by
ADV. The burst address counter may be configured to count in
either linear or interleave order with the Linear Burst Order (LBO)
input. The Burst function need not be used. New addresses can be
loaded on every cycle with no degradation of chip performance.
Parameter Synopsis
Pipeline
3-1-1-1
3.3 V
2.5 V
t
KQ
tCycle
Current
Current
-250 -225 -200 -166 -150 -133 Unit
2.0 2.2 2.5 2.9 3.3 3.5 ns
4.0 4.4 5.0 6.0 6.7 7.5 ns
330
320
300
295
270
265
230
225
215 190
210 185
mA
mA
Rev: 1.02 11/2004
1/28
© 2002, GSI Technology
Specifications cited are subject to change without notice. For latest documentation see http://www.gsitechnology.com.
GS88237AB-250/225/200/166/150/133
GS88237A BGA Pin Description
Symbol
A
0
, A
1
An
DQ
A
DQ
B
DQ
C
DQ
D
B
A
, B
B
, B
C
, B
D
NC
CK
BW
GW
E
1
G
ADV
ADSP, ADSC
ZZ
LBO
SCD
PE
ZQ
TMS
TDI
TDO
TCK
V
DD
V
SS
V
DDQ
V
DDQ
/DNU
Type
I
I
I/O
I
—
I
I
I
I
I
I
I
I
I
I
I
I
I
I
O
I
I
I
I
—
Description
Address field LSBs and Address Counter Preset Inputs
Address Inputs
Data Input and Output pins
Byte Write Enable for DQ
A
, DQ
B
, DQ
C
, DQ
D
I/Os; active low (x36 Version)
No Connect
Clock Input Signal; active high
Byte Write—Writes all enabled bytes; active low
Global Write Enable—Writes all bytes; active low
Chip Enable; active low
Output Enable; active low
Burst address counter advance enable; active low
Address Strobe (Processor, Cache Controller); active low
Sleep Mode control; active high
Linear Burst Order mode; active low
Single Cycle Deselect/Dual Cycle Deselect Mode Control
Parity Bit Enable; active low (High = x16/32 Mode, Low = x18/36 Mode)
FLXDrive Output Impedance Control
(Low = Low Impedance [High Drive], High = High Impedance [Low Drive])
Scan Test Mode Select
Scan Test Data In
Scan Test Data Out
Scan Test Clock
Core power supply
I/O and Core Ground
Output driver power supply
V
DDQ
or V
DD
(must be tied high)
or
Do Not Use (must be left floating)
Rev: 1.02 11/2004
3/28
© 2002, GSI Technology
Specifications cited are subject to change without notice. For latest documentation see http://www.gsitechnology.com.
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