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™Compatible 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 industrial temperature range.
Additional Features
Single Supply with Operation Down to 2.5V
Completely Implements DDC1™/DDC2™Interface for Monitor Identification, IncludingRecovery to DDC1
Pin and Function Compatible with 24LC21
Low-Power CMOS Technology
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
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™Compatible 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 industrial temperature range.
Additional Features
- Single Supply with Operation Down to 2.5V
- Completely Implements DDC1™/DDC2™Interface for Monitor Identification, IncludingRecovery to DDC1
- Pin and Function Compatible with 24LC21
- Low-Power CMOS Technology
- 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
