© 1996 Microchip Technology Inc.

DS21127B-page 1

FEATURES

• Completely implements DDC1

™/DDC2™

interface for monitor identification

• Hardware write-protect pin

• Single supply with operation down to 2.5V

• Low power CMOS technology

- 1 mA active current typical

- 10

µA standby current typical at 5.5V

™ compatible (SCL)

• Self-timed write cycle (including auto-erase)

• Page-write buffer for up to 8 bytes

• 100 kHz (2.5V) and 400 kHz (5V) compatibility

(SCL)

• 10,000,000 erase/write cycles guaranteed

• Data retention > 200 years

• 8-pin PDIP and SOIC package

• Available for extended temperature ranges

DESCRIPTION

The

Microchip

Technology

Inc.

24LCS21

is

a

128 x 8-bit dual-mode Electrically Erasable PROM.

This device is designed for use in applications requiring

storage and serial transmission of configuration and

control information. Two modes of operation have been

implemented: Transmit Only Mode and bi-directional

Mode. Upon power-up, the device will be in the Transmit

Only Mode, sending a serial bit stream of the entire

memory array contents, clocked by the VCLK pin. A

valid high to low transition on the SCL pin will cause the

device to enter the bi-directional Mode, with byte select-

able read/write capability of the memory array in stan-

The 24LCS21 also enables the user to write-protect the

entire memory contents using its write-protect pin. The

24LCS21 is available in a standard 8-pin PDIP and

SOIC package in both commercial and industrial

temperature ranges.

- Commercial (C):

0

°C to +70°C

- Industrial (I)

-40

°C to +85°C

PACKAGE TYPES

BLOCK DIAGRAM

SOIC

1

2

3

4

8

7

6

5

VCLK

SCL

SDA

NC

NC

WP

PDIP

1

2

3

4

8

7

6

5

VCLK

SCL

SDA

NC

NC

WP

I/O

CONTROL

LOGIC

EEPROM

ARRAY

PAGE LATCHES

HV GENERATOR

SENSE AMP

R/W CONTROL

MEMORY

CONTROL

LOGIC

XDEC

YDEC

SDA SCL

VCLK

WP

24LCS21

DDC is a trademark of the Video Electronics Standards Association.

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