AS7C1025 datasheet(2/9 Pages) ALSC

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AS7C1025

AS7C31025

3/23/01; v.1.0

Alliance Semiconductor

P. 2 of 9

Functional description

The AS7C1025 and AS7C31025 are high-performance CMOS 1,048,576-bit Static Random Access Memory (SRAM) devices

organized as 131,072 words × 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 (tAA, tRC, tWC) of 12/15/20 ns with output enable access times (tOE) of 6,7,8 ns are ideal

for 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 AS7C1025 is guaranteed not to exceed 27.5 mW power

consumption in standby mode, and typically requires only 5 mW. 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 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 5V supply (AS7C1025) or 3.3V supply

(AS7C31025). The AS7C1025 and AS7C31025 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

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.

Truth table

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

Parameter

Device

Symbol

Min

Max

Unit

Voltage on VCC relative to GND

AS7C1025

Vt1

–0.50

+7.0

AS7C31025

Vt1

–0.50

+5.0

Voltage on any pin relative to GND

Vt2

–0.50

VCC + 0.5

Power dissipation

–1.0

Storage temperature (plastic)

Tstg

–65

+150

Ambient temperature with VCC applied

Tbias

–55

+125

DC current into outputs (low)

IOUT

–20

Data

Mode

High Z

Standby (ISB, ISB1)

High Z

Output disable (ICC)

LHL

DOUT

Read (ICC)

DIN

Write (ICC)

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