The Microchip 25LC040A is a 4-KB serial EEPROM that uses the industry standard Serial Peripheral Interface (SPI) compatible serial bus. Organised as a 512 x 8-bit block, the device is optimised for use in consumer electronics, industrial, medical and automotive applications where reliable non-volatile storage media is essential. Software write protection allows the user to protect a quarter of, half of or the entire storage array. A hardware write-protect pin is also available, which also protects against accidental writing to the status register and storage array. The EEPROM is available in a variety of space-saving packaging options.