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 informa- tion.
The 24LC21A is a 128‑byte (1 K‑bit) dual‑mode EEPROM that can operate in a transmit‑only mode or a bidirectional I²C‑compatible mode. It supplies a continuous EDID stream on power‑up and switches to full read/write operation when a valid control byte is received on the SCL line.
The device is offered in 8‑pin PDIP and SOIC packages for commercial (0 °C to +70 °C) and industrial (‑40 °C to +85 °C) temperature ranges. It features low active current (≈1 mA), ultra‑low standby current (≈30 µA), 4000 V ESD protection, and a guaranteed 1 M write/erase cycle endurance with data retention exceeding 200 years.
| Supply voltage (Vcc) | 2.5 V to 5.5 V |
|---|---|
| Active write current | ≈1 mA (typical) |
| Standby current | ≈30 µA (typical at 3 V) |
| Write endurance | 1 M cycles |
| Data retention | >200 years |
| ESD protection | >4000 V |
| Operating temperature (commercial) | 0 °C to +70 °C |
| Operating temperature (industrial) | -40 °C to +85 °C |
| Maximum clock frequency | 400 kHz (5 V) |
The device operates from 2.5 V up to 5.5 V.
It is guaranteed for up to 1 million write/erase cycles.
The device supports up to 400 kHz clock frequency at 5 V.
Data is retained for more than 200 years.