1

Features

– Endurance: One Million Write Cycles

– Data Retention: 40 Years

Small Array Package (SAP), 8-lead TSSOP, and 8-ball dBGA2 Packages

Description

The AT24C256B provides 262,144 bits of serial electrically erasable and programma-

ble read-only memory (EEPROM) organized as 32,768 words of 8 bits each. The

device’s cascadable feature allows up to eight devices to share a common two-wire

bus. 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-lead JEDEC PDIP, 8-lead JEDEC SOIC, 8-lead MAP, 8-lead Ultra

Thin SAP, 8-lead TSSOP, and 8-ball dBGA2 packages. In addition, the entire family is

available in a 1.8V (1.8V to 3.6V) version.

Two-wire Serial

EEPROM

256K (32,768 x 8)

AT24C256B

Rev. 5080B–SEEPR–1/07

Table 1. Pin Configurations

Pin Name

Function

A0–A2

Address Inputs

SDA

Serial Data

SCL

Serial Clock Input

WP

Write Protect

NC

No Connect

GND

Ground

A0

A1

A2

GND

VCC

WP

SCL

SDA

1

2

3

4

8

7

6

5

VCC

WP

SCL

SDA

8

7

6

5

1

2

3

4

A0

A1

A2

GND

8

7

6

5

1

2

3

4

VCC

WP

SCL

SDA

A0

A1

A2

GND

8-lead PDIP

8-lead SOIC

8-lead dBGA2

A0

A1

A2

GND

VCC

WP

SCL

SDA

1

2

3

4

8

7

6

5

8-lead TSSOP

Bottom View

8

7

6

5

1

2

3

4

VCC

WP

SCL

SDA

A0

A1

A2

GND

8-lead MAP

Bottom View

8

7

6

5

1

2

3

4

VCC

WP

SCL

SDA

A0

A1

A2

GND

8-lead Ultra Thin SAP

Bottom View