© 1996 Microchip Technology Inc.

DS21140B-page 1

FEATURES

• Single supply with operation down to 2.5V

• Completely implements DDC1

™/DDC2™ interface

for monitor identification

• Separate high speed 2-wire bus for

microcontroller access to 4K-bit Serial EEPROM

• Low power CMOS technology

• 2 mA active current typical

• 20

µA standby current typical at 5.5V

• Dual 2-wire serial interface bus

• Hardware write-protect for both ports

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

• Page-write buffer for up to 8 bytes (DDC port) or

16 bytes (4K Port)

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

• 1,000,000 erase/write cycles guaranteed

• Data retention > 40 years

• 8-pin PDIP package

• Available for extended temperature ranges

DESCRIPTION

The Microchip Technology Inc. 24LC41 is a dual-port

128 x 8 and 512 x 8-bit Electrically Erasable PROM

(EEPROM). This device is designed for use in applica-

tions requiring storage and serial transmission of con-

figuration and control information. Three modes of

operation have been implemented:

• Transmit-Only Mode for the DDC Monitor Port

• Bi-directional Mode for the DDC Monitor Port

• Bi-directional, industry-standard 2-wire bus for the

4K Microcontroller Access Port

Upon power-up, the DDC Monitor Port will be in the

Transmit-Only Mode, repeatedly sending a serial bit

stream of the entire memory array contents, clocked by

the VCLK/DWP pin. A valid high to low transition on the

DSCL pin will cause the device to enter the bi-direc-

tional Mode, with byte-selectable read/write capability

of the memory array. The 4K-bit microcontroller port is

completely independent of the DDC port, therefore, it

can be accessed continuously by a microcontroller

without interrupting DDC transmission activity. The

24LC41 is available in a standard 8-pin PDIP package

in both commercial and industrial temperature ranges.

- Commercial (C):

0

°C to

+70

°C

- Industrial (I):

-40

°C to

+85

°C

PACKAGE TYPE

BLOCK DIAGRAM

DSCL

VCLK/DWP

MSDA

1

2

3

4

8

7

6

5

DSDA

MWP

MSCL

PDIP

EDID Table

1K Bit

4K Bit

Serial

EEPROM

MSDA

MSCL

MWP

DSDA

VCLK/DWP

DSCL

24LC41

DDC is a trademark of the Video Electronics Standards Association.

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