24LCS21A_05 Datasheet, PDF (1/20 Pages) Microchip Technology – 1K 2.5V Dual Mode I2C™ Serial EEPROM

24LCS21A
1K 2.5V Dual Mode I²C^™ Serial EEPROM
Features:
• Single supply with operation down to 2.5V
• Completely implements DDC1™/DDC2™
interface for monitor identification, including
recovery to DDC1
• Low-power CMOS technology:
- 1 mA active current, typical
- 10 μA standby current, typical at 5.5V
• 2-wire serial interface bus, I²C™ compatible
• 100 kHz (2.5V) and 400 kHz (5V) compatibility
• Self-timed write cycle (including auto-erase)
• Hardware write-protect pin
• Page write buffer for up to eight bytes
• 1,000,000 erase/write cycles ensured
• Data retention > 200 years
• ESD Protection > 4000V
• 8-pin PDIP and SOIC package
• Available for extended temperature ranges:
- Commercial (C): 0°C to +70°C
- Industrial (I): -40°C to +70°C
Description:
The Microchip Technology Inc. 24LCS21A 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 configura-
tion and control information. Two modes of operation
have been implemented: Transmit-Only mode and
Bidirectional mode. Upon power-up, the device will be
in the Transmit-Only mode, sending a serial bit stream
of the memory array from 00h to 7Fh, clocked by the
VCLK pin. A valid high-to-low transition on the SCL
pin will cause the device to enter the Transition mode
and look for a valid control byte on the I²C bus. If it
detects a valid control byte from the master, it will
switch into Bidirectional mode, with byte selectable
read/write capability of the memory array using SCL.
If no control byte is received, the device will revert to
the Transmit-Only mode after it receives 128 consec-
utive VCLK pulses while the SCL pin is idle. The
24LCS21A also enables the user to write-protect the
entire memory array using its write-protect pin. The
24LCS21A is available in a standard 8-pin PDIP and
SOIC package in both commercial and industrial
temperature ranges.
DDC is a trademark of the Video Electronics Standards Assoc.
I²C is a trademark of Philips Corporation.
Package Types
PDIP
NC 1
NC 2
WP 3
Vss 4
SOIC
NC ¹
NC ²
WP ³
Vss ⁴
8 Vcc
7 VCLK
6 SCL
5 SDA
8
Vcc
7
VCLK
6
SCL
5
SDA
Block Diagram
WP
HV Generator
I/O
Control
Logic
Memory
Control
Logic
XDEC
SDA ^SCL
VCLK
VCC
VSS
Pin Function Table
EEPROM
Array
Page Latches
YDEC
Sense AMP
R/W Control
Name
WP
VSS
SDA
SCL
VCLK
VCC
NC
Function
Write-Protect (active low)
Ground
Serial Address/Data I/O
Serial Clock (Bidirectional mode)
Serial Clock (Transmit-Only mode)
+2.5V to 5.5V Power Supply
No Connection
© 2005 Microchip Technology Inc.
DS21161G-page 1