GS8640FZ18/36T-5.5/6.5/7.5/8
100-Pin TQFP
Commercial Temp
Industrial Temp
Features
• NBT (No Bus Turn Around) functionality allows zero wait
read-write-read bus utilization; Fully pin-compatible with
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
• Flow Through mode
• LBO pin for Linear or Interleave Burst mode
• Pin compatible with 4Mb, 9Mb, 18Mb and 36Mb devices
• Byte write operation (9-bit Bytes)
• 3 chip enable signals for easy depth expansion
• ZZ Pin for automatic power-down
• JEDEC-standard 100-lead TQFP package
• RoHS-compliant 100-lead TQFP package available
72Mb Flow Through
Synchronous NBT SRAM
5.5 ns–8 ns
2.5 V or 3.3 V V
DD
2.5 V or 3.3 V I/O
available bus bandwidth by eliminating the need to insert
deselect cycles when the device is switched from read to write
cycles.
Because it is a synchronous device, address, data inputs, and
read/ write control inputs are captured on the rising edge of the
input clock. Burst order control (LBO) must be tied to a power
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 off-
chip write pulse generation required by asynchronous SRAMs
and simplifies input signal timing.
The GS8640FZ18/36T is configured to operate in Flow
Through mode.
The GS8640FZ18/36T is implemented with GSI's high
performance CMOS technology and is available in a JEDEC-
standard 100-pin TQFP package.
Functional Description
The GS8640FZ18/36T is a 72Mbit Synchronous Static SRAM.
GSI's NBT SRAMs, like ZBT, NtRAM, NoBL or other flow
through read/single late write SRAMs, allow utilization of all
Parameter Synopsis
-5.5
Flow
Through
2-1-1-1
t
KQ
tCycle
Curr
(x18)
Curr
(x36)
5.5
5.5
285
330
-6.5
6.5
6.5
245
280
-7.5
7.5
7.5
220
250
-8
8.0
8.0
210
240
Unit
ns
ns
mA
mA
Packages listed with the additional “G” designator are 6/6 RoHS compliant.
Rev: 1.01 10/2013
1/21
© 2006, GSI Technology
Specifications cited are subject to change without notice. For latest documentation see http://www.gsitechnology.com.
GS8640FZ18/36T-5.5/6.5/7.5/8
TQFP Pin Descriptions
Symbol
A
0
, A
1
A
CK
B
A
B
B
B
C
B
D
W
E
1
E
2
E
3
G
ADV
CKE
DQ
A
DQ
B
DQ
C
DQ
D
ZZ
LBO
V
DD
V
SS
V
DDQ
NC
Type
In
In
In
In
In
In
In
In
In
In
In
In
In
In
I/O
I/O
I/O
I/O
In
In
In
In
In
—
Description
Burst Address Inputs; Preload the burst counter
Address Inputs
Clock Input Signal
Byte Write signal for data inputs DQ
A1
-DQ
A9
; active low
Byte Write signal for data inputs DQ
B1
-DQ
B9
; active low
Byte Write signal for data inputs DQ
C1
-DQ
C9
; active low
Byte Write signal for data inputs DQ
D1
-DQ
D9
; active low
Write Enable; active low
Chip Enable; active low
Chip Enable; Active High. For self decoded depth expansion
Chip Enable; Active Low. For self decoded depth expansion
Output Enable; active low
Advance/Load; Burst address counter control pin
Clock Input Buffer Enable; active low
Byte A Data Input and Output pins
Byte B Data Input and Output pins
Byte C Data Input and Output pins
Byte D Data Input and Output pins
Power down control; active high
Linear Burst Order; active low
Core power supply
Ground
Output driver power supply
No Connect
Rev: 1.01 10/2013
4/21
© 2006, GSI Technology
Specifications cited are subject to change without notice. For latest documentation see http://www.gsitechnology.com.
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