The M24256 is a 256-Kbit I2C-compatible EEPROM (electrically erasable programmable memory) organized as 32 K × 8 bits.

The M24256-BW can operate with a supply voltage from 2.5 V to 5.5 V, the M24256-BR AND M24256-DR can operate with a supply voltage from 1.8 V to 5.5 V, and the M24256-BF and M24256-DF can operate with a supply voltage from 1.7 V to 5.5 V. All these devices operate with a clock frequency of 1 MHz (or less), over an ambient temperature range of –40 °C / +85 °C. The M24256-D offers an additional page, named the identification page (64 byte). The identification page can be used to store sensitive application parameters which can be (later) permanently locked in read-only mode.