®

AS7C1025A

AS7C31025A

2/6/01; V.0.9

Alliance Semiconductor

P. 2 of 8

Functional description

The AS7C1025A and AS7C31025A are 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.

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 AS7C1025A is guaranteed not to exceed 55 mW power consumption in

standby mode. 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

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 (AS7C1025A) or 3.3V supply (AS7C31025A). The

AS7C1025A and AS7C31025A are packaged in common industry standard packages.

Absolute maximum ratings

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

Key: X = Don’t Care, L = Low, H = High

Parameter

Device

Symbol

Min

Max

Unit

AS7C1025A

–0.50

+7.0

V

AS7C31025A

–0.50

+5.0

V

Voltage on any pin relative to GND

–0.50

V

Power dissipation

–1.0

W

Storage temperature (plastic)

–65

+150

–55

+125

DC current into outputs (low)

–20

mA

CE

WE

OE

Data

Mode

H

X

X

High Z

L

H

H

High Z

LH

L

LL

X