ST24LC21B, ST24LW21, ST24FC21, ST24FC21B, ST24FW21 1 Kbit (x8) Dual Mode Serial EEPROM for VESA PLUG & PLAY is a 1K bit electrically erasable programmable memory (EEPROM), or- ganized in 128x8 bits. It features 1 million erase/write cycles, 40 years data retention, 3.6V to 5.5V or 2.5V to 5.5V single supply voltage, hardware write control (ST24LW21 and ST24FW21), TTL SCHMITT-TRIGGER on VCLK input, 100k / 400k Hz compatibility with the I2C BUS BIT TRANSFER RANGE, two wire serial interface I2C BUS COMPATIBLE, I2C PAGE WRITE (up to 8 Bytes), I2C BYTE, RANDOM and SEQUENTIAL READ MODES, SELF TIMED PROGRAMMING CYCLE, AUTOMATIC ADDRESS INCREMENTING, ENHANCED ESD/LATCH UP PERFORMANCES, ERROR RECOVERY MECHANISM (ST24FC21 and ST24FW21), VESA 2 COMPATIBLE.
This document describes the ST24LC21B, ST24LW21, ST24FC21, ST24FC21B, and ST24FW21 devices, which are 1Kbit electrically erasable programmable memory (EEPROM) organized in 128x8 bits. The products support a single supply voltage ranging from 3.6V to 5.5V or 2.5V to 5.5V and offer up to one million erase/write cycles with 40 years of data retention.
The devices operate in two modes: Transmit-Only mode for VESA PLUG & PLAY applications and I2C bidirectional mode. Key features include hardware write control options, TTL Schmitt-trigger inputs on the clock pin, automatic address incrementing, and enhanced ESD/latch-up performance. Specific models like ST24FC21 and ST24FW21 feature an error recovery mechanism.
| Memory Capacity | 1 Kbit (x8) |
|---|---|
| Organization | 128 x 8 bits |
| Operating Temperature Range | -40 to +85 °C |
| Supply Voltage (VCC) | 3.6V to 5.5V or 2.5V to 5.5V |
| Endurance (Erase/Write Cycles) | 1 Million |
| Data Retention | 40 Years |
ST24LC21B is VESA 1 compatible, while ST24FC21 is VESA 2 compatible.
For ST24LW21 and ST24FW21, the WC signal enables or inhibits write instructions; if WC=1 writes execute, if WC=0 they do not.
It prevents data corruption and inadvertent writes during power up by disabling all operations until VCC reaches the threshold.