®

AS7C4098

AS7C34098

1/13/05; v.1.9

Alliance Semiconductor

P. 2 of 10

Functional description

The AS7C4098 and AS7C34098 are high-performance CMOS 4,194,304-bit Static Random Access Memory (SRAM) devices

organized as 262,144 words × 16 bits. They are designed for memory applications where fast data access, low power, and

simple interfacing are desired.

ideal for high-performance applications. The chip enable input CE permits easy memory expansion with multiple-bank

memory systems.

When CE is High the device enters standby mode. The standard AS7C4098/AS7C34098 is guaranteed not to exceed 110/

72mW power consumption in CMOS standby mode. A write cycle is accomplished by asserting write enable (WE) and chip

enable (CE). Data on the input pins I/O1–I/O16 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.

These devices provide 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/O1–I/O8, and UB controls the higher bits, I/O9–I/O16.

All chip inputs and outputs are TTL- and CMOS-compatible, and operation is from either a single 5V (AS7C4098) or 3.3V

(AS7C34098) supply. Both devices are available in the JEDEC standard 400-mL, 44-pin SOJ and TSOP 2 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

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.

Absolute maximum ratings

Parameter

Device

Symbol

Min

Max

Unit

AS7C4098

–0.50

+7.0

V

AS7C34098

–0.50

+5.0

V

Voltage on any pin relative to GND

–0.50

V

Power dissipation

–1.5

W

Storage temperature

–65

+150

°C

–55

+125

°C

DC current into outputs (low)

–±20

mA

Truth table

CE

WE

OE

LB

UB

I/O1–I/O8

I/O9–I/O16

Mode

HXXXX

High Z

High Z

L

HHXX

High Z

High Z

L

XXHH

LHL

LH

High Z

HL

High Z

LL

LL

X

LH

High Z

HL

High Z

LL

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