93AA66CX-I/SN is an 8-pin serial EEPROM chip manufactured by Microchip Technology Inc. It is a 64Kbit (8Kbyte) memory device with an SPI interface. It features an extended temperature range (-40°C to +85°C). It has a unique 56-bit serial number that allows it to be used for authentication applications. It also includes on-chip error correction and write-protection.