• Default to SCD x36/x72 Interleaved Pipeline mode
• Byte Write (BW) and/or Global Write (GW) operation
• Internal self-timed write cycle
• Automatic power-down for portable applications
• JEDEC-standard 119- and 209-bump BGA package
-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)
2.3
4.0
365
560
660
360
550
640
6.0
7.0
235
300
350
235
300
340
2.5
4.4
335
510
600
330
500
590
6.5
7.5
230
300
350
230
300
340
3.0
3.5
5.0
6.0
305
265
460
400
540
460
305
260
460
390
530
450
7.5
8.51010101115ns
8.5
210
200
270
270
300
300
210
200
270
270
300
300
3.8
6.6
245
370
430
240
360
420
195
270
300
195
270
300
4.0
7.5nsns
215
mA
330
mA
380
mA
215
mA
330
mA
370
mA
150
mA
200
mA
220
mA
145
mA
190
mA
220
mA
ns
Functional Description
Applications
The GS832418/36/72 is a 37,748,736-bit high performance 2-die
synchronous SRAM module 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-edgetriggered clock input (CK). Output enable (G) and power down
control (ZZ) are asynchronous inputs. Burst cycles can be initiated
250 MHz–133MHz
2.5 V or 3.3 V V
DD
2.5 V or 3.3 V I/O
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.
Flow Through/Pipeline Reads
The function of the Data Output register can be controlled by the
user via the FT mode . Holding the FT mode pin low places the
RAM in Flow Through mode, causing output data to bypass the
Data Output Register. Holding FT high places the RAM in
Pipeline mode, activating the rising-edge-triggered Data Output
Register.
SCD and DCD Pipelined Reads
The GS832436(B/C) and the GS832472(C) are SCD (Single
Cycle Deselect) and DCD (Dual Cycle Deselect) pipelined
synchronous SRAMs. The GS832418(B/C) is a DCD-only
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 the x36 or x72 versions of 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 GS832418/36/72 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
) pins are used to decouple output noise from the internal
Specifications cited are subject to change without notice. For latest documentation see http://www.gsitechnology.com.
ByteSafe is a Trademark of Giga Semiconductor, Inc. (GSI Technology).
IGlobal Write Enable—Writes all bytes; active low
IChip Enable; active low
IChip Enable; active low (x72/x36 Versions)
IChip Enable; active high (x72/x36 Versions)
Byte Write Enable for DQC, DQD I/Os; active low
(x72/x36 Versions)
Byte Write Enable for DQE, DQF, DQG, DQH I/Os; active low
IOutput Enable; active low
IBurst address counter advance enable; active low
IAddress Strobe (Processor, Cache Controller); active low
ISleep Mode control; active high
IFlow Through or Pipeline mode; active low
ILinear Burst Order mode; active low
I
IMust Connect High
IMust Connect High (x18 version)
IByte Enable; active low
I
IScan Test Mode Select
IScan Test Data In
OScan Test Data Out
IScan Test Clock
ICore power supply
II/O and Core Ground
IOutput driver power supply
Single Cycle Deselect/Dual Cycle Deselect Mode Control (
x72/x36 Versions)
Must Connect Low
Must Connect Low (x18 version)
FLXDrive Output Impedance Control
(Low = Low Impedance [High Drive], High = High Impedance [Low
Specifications cited are subject to change without notice. For latest documentation see http://www.gsitechnology.com.
Die B
x36
32Mb
Linear Burst Sequence
I
Mode Pin Functions
Preliminary
GS832418(B/C)/GS832436(B/C)/GS832472(C)
Mode Name
Burst Order ControlLBO
Output Register ControlFT
Power Down ControlZZ
Single/Dual Cycle Deselect ControlSCD
FLXDrive Output Impedance ControlZQ
Note:
There are pull-up devices on the ZQ, SCD and FT pins and a pull-down device on the ZZ pin, so those input pins can be unconnected and the
chip will operate in the default states as specified in the above tables.
Pin
Name
StateFunction
LLinear Burst
HInterleaved Burst
LFlow Through
H or NCPipeline
L or NCActive
H
LDual Cycle Deselect
H or NCSingle Cycle Deselect
LHigh Drive (Low Impedance)
H or NCLow Drive (High Impedance)
Standby, IDD = I
SB
Enable / Disable Parity I/O Pins
This SRAM allows the user to configure the device to operate in Parity I/O active (x18, x36, or x72) or in Parity I/O inactive (x16,
x32, or x64) mode. Holding the PE bump low or letting it float will activate the 9th I/O on each byte of the RAM. Grounding PE
deactivates the 9th I/O of each byte, although the bit in each byte of the memory array remains active to store and recall parity bits
generated and read into the ByteSafe parity circuits.
Burst Counter Sequences
nterleaved Burst Sequence
A[1:0] A[1:0] A[1:0] A[1:0]
1st address00011011
2nd address01101100
3rd address10110001
4th address11000110
Note: The burst counter wraps to initial state on the 5th clock.