1

Features

– 5.0 (V

– 2.7 (V

– 1.8 (V

– Endurance: 100,000 Write Cycles

– Data Retention: 40 Years

– ESD Protection: >4000V

Description

The AT24CS128/256 provides 131,072/262,144 bits of serial electrically erasable and

programmable read only memory (EEPROM) organized as 16,384/32,768 words of 8

bits each. The device’s cascadable feature allows up to 4 devices to share a common

2-wire bus. The device also features a one-time programmable 2048 bit array, which

once enabled, becomes read-only and cannot be overwritten. If not enabled, the OTP

section will function as part of the normal memory array. The device is optimized for

use in many industrial and commercial applications where low power and low voltage

operation are essential. The devices are available in space-saving 8-pin JEDEC PDIP

(AT24CS128/256), 8-pin EIAJ (AT24CS128/256), 8-pin JEDEC SOIC (AT24CS128)

packages. In addition, the entire family is available in 5.0V (4.5V to 5.5V), 2.7V (2.7V

to 5.5V) and 1.8V (1.8V to 3.6V) versions.

Rev. 1152A–09/98

2-Wire Serial

EEPROMs

with Permanent

Software Write

Protect

128K (16,384 x 8)

256K (32,768 x 8)

AT24CS128

AT24CS256

with Permanent

Software Write

Protect

Advanced

Information

Pin Configurations

Pin Name

Function

A0 to A2

Address Inputs

SDA

Serial Data

SCL

Serial Clock Input

WP

Write Protect

8-Pin PDIP

1

2

3

4

8

7

6

5

A0

A1

A2

GND

VCC

WP

SCL

SDA

8-Pin SOIC

1

2

3

4

8

7

6

5

A0

A1

A2

GND

VCC

WP

SCL

SDA