ST24LC21B, ST24LW21 ST24FC21, ST24FC21B, ST24FW21 1 Kbit (x8) Dual Mode Serial EEPROM for VESA PLUG & PLAY are 1K bit electrically erasable programmable memory (EEPROM), organized in 128x8 bits.
The ST24 family comprises 1 Kbit (x8) dual‑mode serial EEPROMs compatible with VESA PLUG & PLAY standards. They offer up to 1 million erase/write cycles, 40 years data retention, and operate from 3.6 V to 5.5 V (or 2.5 V to 5.5 V single‑supply). The devices support both transmit‑only and I²C bidirectional modes, with optional hardware write‑control (WC) on selected parts.
The datasheet provides pin‑out diagrams for DIP‑8 and SO‑8 packages, absolute maximum ratings, DC characteristics, and timing parameters. It also describes power‑on reset behavior, error‑recovery mechanisms, and the unique 4‑bit device‑select code used for I²C addressing.
| Memory size | 1 Kbit (x8) |
|---|---|
| Supply voltage | 3.6 V to 5.5 V (or 2.5 V to 5.5 V single‑supply) |
| Erase/write cycles | 1 million |
| Data retention | 40 years |
| Ambient temperature range | ‑40 °C to 85 °C |
| Supply voltage rating (absolute max) | -0.3 V to 6.5 V |
| Write Control pin (WC) | Available on ST24LW21 and ST24FW21 |
They operate from 3.6 V to 5.5 V, or from 2.5 V to 5.5 V for single‑supply versions.
The devices are rated for up to 1 million erase/write cycles.
Data can be retained for 40 years.