The 24LC256-I/SM is a 256K (32K x 8) Serial Electrically Erasable Programmable Read-Only Memory (EEPROM) from Microchip. It is organized as 32K words of 8 bits each, and can be accessed through a 2-wire serial interface. This device supports data retention of up to 200 years and is compatible with both I2C and two-wire (software-compatible) buses. The 24LC256-I/SM is pin and functionally compatible with the existing 24C256-I/SM device, with an improved write cycle time of at most 10ms. This device has Built-in self-timed write cycle (with auto-erase and byte-write) which guarantee the content of the memory is not affected by sudden power loss. Features include a low-power CMOS technology, 150 kHz two-wire serial interface with Schmitt triggers, 1.0 MHz two-wire serial interface with Schmitt triggers, and standby mode. It operates between -40°C to 85°C temperature range and is available in 8-pin PDIP, SOIC and TSSOP packages.