The AS7C1025 and AS7C31025 are high-performance CMOS 1,048,576-bit Static Random Access Memory (SRAM) devices
organized as 131,072 words × 8 bits. They are 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 12/15/20 ns with output enable access times (t
OE
) of 6,7,8 ns are ideal
for high-performance applications. The chip enable input CE permits easy memory and expansion with multiple-bank
memory systems.
When
CE
is high the devices enter standby mode. The standard AS7C1025 is guaranteed not to exceed 27.5 mW power
consumption in standby mode, and typically requires only 5 mW Both devices also offer 2.0V data retention.
.
A write cycle is accomplished by asserting write enable (
WE
) and chip enable (
CE
). Data on the input pins I/O0-I/O7 is
written on the rising edge of
WE
(write cycle 1) or
CE
(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 chip enable (
CE
), with write enable (
WE
) high. The chips
drive 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 (AS7C1025) or 3.3V supply
(AS7C31025). The AS7C1025 and AS7C31025 are packaged in common industry standard packages.
Absolute maximum ratings
Parameter
Voltage on V
CC
relative to GND
Voltage on any pin relative to GND
Power dissipation
Storage temperature (plastic)
Ambient temperature with V
CC
applied
DC current into outputs (low)
Device
AS7C1025
AS7C31025
Symbol
V
t1
V
t1
V
t2
P
D
T
stg
T
bias
I
OUT
Min
–0.50
–0.50
–0.50
–
–65
–55
–
Max
+7.0
+5.0
V
CC
+ 0.5
1.0
+150
+125
20
Unit
V
V
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 functional
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
CE
H
L
L
L
WE
X
H
H
L
OE
X
H
L
X
Data
High Z
High Z
D
OUT
D
IN
Mode
Standby (I
SB
, I
SB1
)
Output disable (I
CC
)
Read (I
CC
)
Write (I
CC
)
Key: X = Don’t Care, L = Low, H = High
3/23/01; v.1.0
Alliance Semiconductor
P. 2 of 9
®
AS7C1025
AS7C31025
Recommended operating conditions
Parameter
Supply voltage
Device
AS7C1025
AS7C31025
AS7C1025
Input voltage
AS7C31025
commercial
industrial
Symbol
V
CC
V
CC
V
IH
V
IH
V
IL†
Ambient operating temperature
†
V
IL
min = –3.0V for pulse width less than t
RC
/2.
Min
4.5
3.0
2.2
2.0
–0.5
0
–40
Nominal
5.0
3.3
–
–
–
–
–
Max
5.5
3.6
V
CC
+ 0.5
V
CC
+ 0.5
0.8
70
85
Unit
V
V
V
V
V
o
C
o
T
A
T
A
C
DC operating characteristics (over the operating range)
编程基础
