The AS7C164 is a high performance CMOS 65,536-bit Static Random Access Memory (SRAM) organized as 8,192 words × 8
bits. It is designed for memory applications where fast data access, low power, and simple interfacing are desired.
Equal address access and cycle times (t
AA
, t
RC
, t
WC
) of 8/10/12/15/20 ns with output enable access times (t
OE
) of 3/3/3/4/
5 ns are ideal for high performance applications. Active high and low chip enables (CE1, CE2) permit easy memory expansion
with multiple-bank memory systems.
When CE1 is HIGH or CE2 is LOW the device enters standby mode. The standard AS7C164 is guaranteed not to exceed 11.0
mW power consumption in standby mode; the L version is guaranteed not to exceed 1.1 mW, and typically requires only 250
µW.
The L version also offers 2.0V data retention, with maximum power of 120 µW.
A write cycle is accomplished by asserting write enable (WE) and both chip enables (CE1, CE2). Data on the input pins I/O0-
I/O7 is written on the rising edge of WE (write cycle 1) or the active-to-inactive edge of CE1 or CE2 (write cycle 2). To avoid
bus contention, external devices should drive I/O pins only after outputs have been disabled with output enable (OE) or write
enable (WE).
A read cycle is accomplished by asserting output enable (OE) and both chip enables (CE1, CE2), with write enable (WE)
HIGH. The chip drives I/O pins with the data word referenced by the input address. When either chip enable or output enable
is inactive, or write enable is active, output drivers stay in high-impedance mode.
All chip inputs and outputs are TTL-compatible, and operation is from a single 5V supply. The AS7C164 is packaged in all
high volume industry standard packages.
Absolute maximum ratings
Parameter
Voltage on any pin relative to GND
Power dissipation
Storage temperature (plastic)
Temperature under bias
DC output current
Symbol
V
t
P
D
T
stg
T
bias
I
out
Min
–0.5
–
–55
–10
–
Max
+7.0
1.0
+150
+85
20
Unit
V
W
o
C
o
C
mA
NOTE: Stresses greater than those listed under Absolute Maximum Ratings may cause permanent damage to the device. This is a stress rating only and func-
tional operation of the device at these or any other conditions outside those indicated in the operational sections of this specification is not implied. Exposure
to absolute maximum rating conditions for extended periods may affect reliability.
Truth table
CE1
H
X
L
L
L
CE2
X
L
H
H
H
WE
X
X
H
H
L
OE
X
X
H
L
X
Data
High Z
High Z
High Z
D
out
D
in
Mode
Standby (I
SB
, I
SB1
)
Standby (I
SB
, I
SB1
)
Output disable
Read
Write
Key: X = Don’t Care, L = LOW, H = HIGH
2
AS7C164
AS7C164L
Recommended operating conditions
Symbol
V
CC
Supply voltage
GND
V
IH
Input voltage
V
IL
Ambient operating temperature
* V
IL
min = –3.0V for pulse width less than t
RC
/2.
Applicable to all portions of this specification unless otherwise noted.
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