AS7C1024A
AS7C31024A
®
Functional description
The AS7C1024A and AS7C31024A are high performance CMOS 1,048,576-bit Static Random Access Memory (SRAM) devices organized as
131,072 words x 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 , t , t ) of 10/ 12/ 15/ 20 ns with output enable access times (t ) of 5, 6, 7, 8 ns are ideal for high
AA RC WC
OE
performance applications. Active high and low chip enables (CE1, CE2) permit easy memory expansion with multiple-bank systems.
When CE1 is high or CE2 is low the devices enter standby mode. If inputs are still toggling, the device will consume I power. If the bus is
SB
static, then full standby power is reached (I ). For example, the AS7C31024A is guaranteed not to exceed 36mW under nominal full standby
SB1
conditions. All devices in this family will retain data when VCC is reduced as low as 2.0V.
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 chips drive
I/ O pins with the data word referenced by the input address. When either chip enable is inactive, output enable is inactive, or write enable is
active, output drivers stay in high-impedance mode.
Absolute maximum ratings
Parameter
Symbol
Min
–0.50
-0.50
–0.50
–
Max
+7.0
Unit
V
AS7C1024A
AS7C31024A
Both
V
t1
Voltage on VCC relative to GND
V
+5.0
V
t1
Voltage on any pin relative to GND
Power dissipation
V
VCC +0.50
1.0
V
t2
Both
PD
W
Storage temperature (plastic)
Ambient temperature with VCC applied
DC current into outputs (low)
Both
Tstg
–65
–55
–
+150
+125
20
°C
°C
mA
Both
Tbias
IOUT
Both
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 oper-
ation 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
CE2
X
WE
X
OE
X
Data
Mode
H
High Z
High Z
High Z
DOUT
Standby (ISB, ISB1
Standby (ISB, ISB1
)
)
X
L
X
X
L
H
H
H
Output disable (ICC)
Read (ICC)
L
H
H
L
L
H
L
X
D
Write (ICC)
IN
Key: X = Don’t Care, L = Low, H = High
9/ 26/ 02; 0.9.9
Alliance Semiconductor
P. 2 of 9
ALSC [ ALLIANCE SEMICONDUCTOR CORPORATION ]
