3.

Description

The AT24CSW01X/AT24CSW02X provides 1,024/2,048 bits of Serial Electrically Erasable and Programmable Read-

Only Memory (EEPROM) organized as 128/256 words of 8 bits each. The device is optimized for use in many

industrial and commercial applications where low-power and low-voltage operation are essential.

The device features a software write protection feature with five different programmable levels of protection for the

EEPROM array. The protection settings of the device can be made permanent, if desired. Safeguards are included to

prevent accidental invocation of the permanent feature.

Additionally, each device includes a Security register with an extra 256 bits of EEPROM beyond the nominal

EEPROM array. The Security register is comprised of a read-only section of 16 bytes and an additional user-

programmable section of 16 bytes.

The Security register begins with a read-only section that contains a factory programmed, ensured unique 128-

bit serial number. The time-consuming step of performing and ensuring true serialization of a product on a

manufacturing line can be removed from the production flow by employing a CS or CSW Series Serial EEPROM.

The 128-bit serial number is programmed and permanently locked from future writing during the Microchip production

process. Further, this 128-bit location does not consume any of the user read/write area of the 1-Kbit or 2-Kbit Serial

EEPROM. The uniqueness of the serial number is ensured across the entire CS or CSW Series of Serial EEPROMs,

regardless of the size of the memory array or the type of interface protocol. This means that as an application’s

needs for memory size or interface protocol evolve in future generations, any previously deployed serial number from

any CS or CSW Series Serial EEPROM part will remain valid.

Following the 128-bit read-only serial number in the Security register is an additional 16 bytes of EEPROM organized

as two pages of 8 bytes each. This region of the Security register is user-programmable and, if desired, can later

be permanently write protected with a software sequence. This user-programmable section of the Security register is

ideal for applications that need to irreversibly protect critical or sensitive application data.

The AT24CSW01X/AT24CSW02X is available in 5-lead SOT23 and best-in-class 4-ball Ultra-Thin WLCSP packages

The device operates with a supply voltage ranging from 1.7V to 3.6V.

3.1

System Configuration Using Two-Wire Serial EEPROMs

Microcontroller

GND

SCL

SDA

Client 0

AT24CSW010

AT24CSW020

WP

SDA

SCL

GND

Client 7

AT24CSW017

AT24CSW027

WP

SDA

SCL

GND

Client 1

AT24CSW011

AT24CSW021

WP

SDA

SCL

GND

WP

Note:  The WP pin is only available on the 5-lead SOT23 package.

AT24CSW01X/AT24CSW02X

Description

and its subsidiaries

Datasheet

DS20006396B-page 7