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

m

A 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
24LC41
DSCL
VCLK/DWP
VSS
MSDA
1
2
3
4
8
7
6
5
DSDA
VCC
MWP
MSCL
PDIP
EDID Table
1K Bit
4K Bit
Serial
EEPROM
MSDA
MSCL
MWP
DSDA
VCLK/DWP
DSCL
DDC Monitor Port
Microcontroller Access
Port

24LC41

1K/4K 2.5V Dual Mode, Dual Port I

2

C



Serial EEPROM

DDC is a trademark of the Video Electronics Standards Association.
I

2

C is a trademark of Philips Corporation.

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