®
AS7C1026B
3/26/04, v 1.3 Alliance Semiconductor P. 2 of 10
Functional description
The AS7C1026B is a 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 desired.
Equal address access and cycle times (t
AA
, t
RC
, t
WC
) of 10/12/15/20 ns with output enable access times (t
OE
) of 5, 6, 7, 8 ns are ideal for
high-performance applications.
When 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
). For example, the AS7C1026B is guaranteed not to exceed 55 mW under nominal full standby conditions.
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 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.
The device provides multiple center power and ground pins, and separate byte enable controls, allowing individual bytes to be written 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 5 V supply. The device 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 absolute 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 +7.0 V
Voltage on any pin relative to GND V
t2
–0.50 V
CC
+0.50 V
Power dissipation P
D
–1.0W
Storage temperature (plastic) T
stg
–65 +150 °C
Ambient temperature with VCC
applied
T
bias
–55 +125 °C
DC current into outputs (low) I
OUT
–20mA
Truth table
CE WE OE LB UB I/O0–I/O7 I/O8–I/O15 Mode
HXXXXHigh ZHigh Z Standby (I
SB
), I
SBI
)
LHLLHD
OUT
High Z Read I/O0–I/O7 (I
CC
)
LHLHLHigh ZD
OUT
Read I/O8–I/O15 (I
CC)
LHLLLD
OUT
D
OUT
Read I/O0–I/O15 (I
CC
)
LLXLL D
IN
D
IN
Write I/O0–I/O15 (I
CC
)
LLXLHD
IN
High Z Write I/O0–I/O7 (I
CC
)
LLXHLHigh ZD
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
)
