Electrically Erasable Programmable Read-Only Memory (EEPROM)

EEPROM, with the help of an electric field, is eraseable and reprogrammable, but with a shorter lifetime. This means that it only may be reprogrammed tens to hundreds of thousands of times. This is far more limited than modern EEPROM, which may be reprogrammed a million times. Additionally, to perform a rewrite, EEPROM chips must be completely erased, unlike other read-only memory (ROM) models.

The following are the primary electrical interface categories for EEPROM devices:

• Serial bus: Serial EEPROM generally functions in three different phases - Address Phase, Data Phase and OP-Code Phase. Most familiar types of serial interface are Microwire, SPI, 1-Wire, I²C and UNI/O.
• Parallel bus: A parallel EEPROM device usually includes a data bus of eight bits and a wide enough address bus for total memory handling. The majority of devices include write-protect and chip select pins. Many microcontrollers also include built-in parallel EEPROM.
  

EEPROM is mainly used in devices (like digital potentiometers, digital temperature sensors and real-time clocks) to save calibration or similar data that is required when the power is switched off or removed.

EEPROMs are recognized as arrays of floating gate transistors.