2003 Microchip Technology Inc.
DS21176D-page 1
24LC41A
Features
Single supply with operation down to 2.5V
Completely implements DDC1
/DDC2
interface
for monitor identification, including recovery to
DDC1
Improved noise immunity
Separate high speed 2-wire bus for
microcontroller access to 4K-bit Serial EEPROM
Low-power CMOS technology
2 mA active current typical
20
μ
A standby current typical at 5.5V
Dual 2-wire serial interface bus, I
2
C
compatible
Hardware write-protect for Microcontroller Access
Port
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
Data retention > 40 years
8-pin PDIP package
Available for extended temperature ranges
- Commercial (C):
- Industrial (I):
Description
The Microchip Technology Inc. 24LC41A 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
configuration and control information. Three modes of
operation have been implemented:
Transmit-only mode for the DDC Monitor Port
Bidirectional mode for the DDC Monitor Port
Bidirectional, 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 pin. A valid high-to-low transition on the
DSCL pin will cause the device to enter the transition
mode, an look for a valid control byte on the I
2
C bus. If
it detects a valid control byte from the master, it will
switch to Bidirectional mode, with byte selectable read/
write capability of the memory array using DSCL. If no
control byte is received, the device will revert to the
Transmit-only mode after it received 128 consecutive
VCLK Package Type pulses while the DSCL pin is idle.
The 4K-bit microcontroller port is completely indepen-
dent of the DDC port, therefore, it can be accessed
continuously by a microcontroller without interrupting
DDC transmission activity. The 24LC41A is available in
a standard 8-pin PDIP package in both commercial and
industrial temperature ranges.
Package Type
Block Diagram
Pin Function Table
0
°
C
-40
°
C to
to
+70°C
+85
°
C
Name
Function
DSCL
Serial Clock for DDC Bidirectional mode
(DDC2)
Serial Address and Data I/O(DDC Bus)
Serial Clock for DDC Transmit-only mode
(DDC1)
Serial clock for 4K-bit MCU port
Serial Address and Data I/O for 4K-bit MCU port
Hardware write-protect for Microcontroller
Access Port
Ground
+2.5V to +5.5V power supply
DSDA
VCLK
MSCL
MSDA
MWP
V
SS
V
CC
2
PDIP
DSCL
VCLK
V
SS
MSDA
1
2
3
4
DSDA
Vcc
MWP
MSCL
8
7
6
5
EDID Table
1K-Bit
4K-Bit
Serial
EEPROM
MSDA
MSCL
D
M
DSDA
VCLK
DSCL
1K/4K 2.5V Dual Mode, Dual Port I
2
C Serial EEPROM
DDC is a trademark of Video Electronics Standards Association.
I
2
C is a trademark of Philips Corporation.