AS7C1025C
12/5/06, v. 1.0 Alliance Memory P. 2 of 9
®
Functional description
The AS7C1025C is a 5V high-performance CMOS 1,048,576-bit Static Random Access Memory (SRAM) devices organized
as
131,072 x 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 15 ns with output enable access times (t
OE
) of 6 ns are ideal for high-
performance applications. The chip enable input CE permits easy memory and expansion with multiple-bank memory
systems.
Whe
n CE is high, the device enters standby mode. If inputs are still toggling, the device will consume I
SB
power. If the bus is
static, then full standby power is reached (I
SB1
).
A write cycle is accomplished by asserting write enable (
WE
) and chip enable (
CE
). Data on the input pins I/O0 through 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
dr
ive 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 5 V supply. The AS7C1025C is packaged in
common industry standard packages.
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.
Key: X = don’t care, L = low, H = high.
Absolute maximum ratings
Parameter Symbol Min Max Unit
Voltage on V
CC
relative to GND V
t1
–0.50 +7.0 V
Voltage on any pin relative to GND V
t2
–0.50 V
CC
+ 0.5 V
Power dissipation P
D
– 1.25 W
Storage temperature (plastic) T
stg
–55 +125
o
C
Ambient temperature with V
CC
applied T
bias
–55 +125
o
C
DC current into outputs (low) I
OUT
– 50 mA
Truth table
CE WE OE
Data Mode
H X
X High Z Standby (I
SB
, I
SB1
)
L H H High Z Output disable (I
CC
)
L H L D
OUT
Read (I
CC
)
L L X D
IN
Write (I
CC
)
