AS7C31026C
9/20/06, v 2.0Alliance MemoryP. 2 of 10
®
Functional description
The AS7C31026C is a 3V high-performance CMOS 1,048,576-bit Static Random Access Memory (SRAM) device organized
as 65,536 words × 16 bits. It is designed for memory applications where fast data access, low power, and simple interfacing
are de
sired.
Equal address access
and cycle times (t
AA
, t
RC
, t
WC
) of 12 ns with output enable access times (t
OE
) of 6 ns are ideal for high-
performance applications.
When CE
is high, the device enters standby mode. A write cycle is accomplished by asserting write enable (WE) and chip
enable (CE
). Data on the input pins I/O0 through I/O15 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.
The devi
ce provides multiple center power and ground pins, and separate byte enable controls, allowing individual bytes to be
writte
n and read. LB
controls the lower bits, I/O0 through I/O7, and UB controls the higher bits, I/O8 through I/O15.
All chip inputs and outputs are TTL-compatible, and operation is from a single 3.3 V supply. The AS7C31026C 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 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 abs
olute maximum rating conditions for extended periods may affect reliability.
Key: H = high, L = low, X = don’t care.
Absolute maximum ratings
Parameter Symbol Min Max Unit
Voltage on V
CC
relative to GND V
t1
–0.50 +4.60 V
Voltage on any pin relative to GND V
t2
–0.50 V
CC
+0.50 V
Power dissipation P
D
– 1.25 W
Storage temperature (plastic) T
stg
–55 +125 °C
Ambient temperature with VCC applied T
bias
–55 +125 °C
DC current into outputs (low) I
OUT
– 50 mA
Truth table
CE WE OE LB UB I/O0–I/O7 I/O8–I/O15 Mode
H X X X X High Z High Z Standby (I
SB
), I
SBI
)
L H L L H D
OUT
High Z Read I/O0–I/O7 (I
CC
)
L H L H L High Z D
OUT
Read I/O8–I/O15 (I
CC)
L H L L L D
OUT
D
OUT
Read I/O0–I/O15 (I
CC
)
L L X L L D
IN
D
IN
Write I/O0–I/O15 (I
CC
)
L L X L H D
IN
High Z Write I/O0–I/O7 (I
CC
)
L L X H L High Z D
IN
Write I/O8–I/O15 (I
CC
)
L
L
H
X
H
X
X
H
X
H
High Z High Z Output disable (I
CC
)
