24LC41A Datasheet, PDF (1/18 Pages) Microchip Technology – 1K/4K 2.5V Dual Mode, Dual Port I2C™ Serial EEPROM

24LC41A
1K/4K 2.5V Dual Mode, Dual Port I²C™ Serial EEPROM
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 µA standby current typical at 5.5V
• Dual 2-wire serial interface bus, I²C^™ 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):
0°C to +70°C
-40°C to +85°C
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 I²C 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
PDIP
DSCL 1
8 DSDA
VCLK 2
7 Vcc
VSS 3
6 MWP
MSDA 4
5 MSCL
Block Diagram
EDID Table
1K-Bit
MSDA
4K-Bit
Serial
EEPROM
DSDA
VCLK
DSCL
MSCL
Pin Function Table
Name
Function
DSCL
DSDA
VCLK
MSCL
MSDA
MWP
VSS
VCC
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
I²C is a trademark of Philips Corporation.
DDC is a trademark of Video Electronics Standards Association.
 2003 Microchip Technology Inc.
DS21176D-page 1