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ADVANCEDINFORMATION

Rev. 00B

03/11/03

IS24C256

Copyright © 2003 Integrated Silicon Solution, Inc. All rights reserved. ISSI reserves the right to make changes to this specification and its products at any time without notice. ISSI assumes no liability

arising out of the application or use of any information, products or services described herein. Customers are advised to obtain the latest version of this device specification before relying on any

published information and before placing orders for products.

262,144-bit 2-WIRE SERIAL

CMOS EEPROM

FEATURES

• Organization:

– 32K-bit x 8-bit

• 64-Byte Page Write Buffer

• Two-Wire Serial Interface

– Bi-directional data transfer protocol

• Low Power CMOS Technology

– Active Current less than 3 mA (5V)

– Standby Current less than 6 µA (5V)

– Standby Current less than 2 µA (2.5V)

• Wide Voltage Operation

– IS24C256-2: Vcc = 1.8V to 5.5V

– IS24C256-3: Vcc = 2.5V to 5.5V

ADVANCED INFORMATION

MARCH 2003

• Hardware Data Protection

– Write Protect pin

• Sequential Read Feature

• Filtered Inputs for Noise Suppression

• Self time Write cycle with auto clear

– 5 ms @ 5.0V

• High Reliability

– Endurance: 100,000 Cycles

– Data Retention: 40 Years

• Commercial and Industrial temperature ranges

•

8-pin PDIP, 8-pin SOIC, and 14-pin TSSOP

DESCRIPTION

The IS24C256 is an electrically erasable PROM device

that uses the standard 2-wire interface for

communications. The IS24C256 contains a memory

array of 256K-bits (32,768 x 8), and is further

subdivided into 512 pages of 64 bytes each for Page-

Write mode. This EEPROM is offered in wide operating

voltages of 1.8V to 5.5V (IS24C256-2) and 2.5V to 5.5V

(IS24C256-3) to be compatible with most application

voltages. ISSI designed the IS24C256 to be a low-cost

and low-power 2-wire EEPROM solution. The devices

are packaged in 8-pin PDIP, 8-pin SOIC, and 14-pin

TSSOP.

The IS24C256 maintains compatibility with the popular

2-wire bus protocol, so it is easy to design into

applications implementing this bus type. The simple

bus consists of the Serial Clock wire (SCL) and the

Serial Data wire (SDA). Using the bus, a Master device

such as a microcontroller is usually connected to one

or more Slave devices such as the IS24C256. The bit

stream over the SDA line includes a series of bytes,

which identifies a particular Slave device, an

instruction, an address within that Slave device, and a

series of data, if appropriate. The IS24C256 has a Write

Protect pin (WP) to allow blocking of any write

instruction transmitted over the bus.