Description

The Microchip Technology Inc. 24LC21A 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 configuration 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 consecutive VCLK pulses while the SCL pin is idle. The 24LC21A is available in a standard 8-pin PDIP and SOIC package in both commercial and industrial temperature ranges.

Features

? Single supply with operation down to 2.5V

? Completely implements DDC1?/DDC2? interface for monitor identification, including recovery to DDC1

? Pin and function compatible with 24LC21

? Low-power CMOS technology

- 1 mA typical active current

- 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)

? 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 +85°C