# EEPROM

> nonvolatile memory comprising arrays of floating-gate transistors used in computers and microcontrollers to store relatively small amounts of data but allowing individual bytes to be erased/reprogrammed in-circuit through special programming signals

**Wikidata**: [Q205908](https://www.wikidata.org/wiki/Q205908)  
**Wikipedia**: [English](https://en.wikipedia.org/wiki/EEPROM)  
**Source**: https://4ort.xyz/entity/eeprom

## Summary
EEPROM (Electrically Erasable Programmable Read-Only Memory) is a type of nonvolatile memory that uses floating-gate transistors to store data that persists without power, while allowing individual bytes to be erased and reprogrammed in-circuit through special programming signals. This capability makes it ideal for small data storage needs in computers and microcontrollers where occasional updates are required.

## Key Facts
- EEPROM stands for Electrically Erasable Programmable Read-Only Memory and is a subclass of erasable programmable read-only memory
- It comprises arrays of floating-gate transistors that can be electrically erased and reprogrammed
- EEPROM maintains stored data without requiring power (nonvolatile memory)
- It allows individual bytes to be erased and reprogrammed in-circuit through special programming signals
- It is typically used to store relatively small amounts of data in computers and microcontrollers
- EEPROM has 43 sitelinks across various language Wikipedia editions
- The technology has different aliases including E²PROM, E2PROM, and Memoria EEPROM
- EEPROM can be distinguished from EPROM which requires UV light for erasure rather than electrical signals

## FAQs
### Q: How does EEPROM differ from traditional ROM?
A: Unlike traditional ROM (Read-Only Memory), EEPROM can be electrically erased and reprogrammed in-circuit without special equipment or UV light exposure, allowing for data modification while still maintaining nonvolatile storage.

### Q: What is the typical data storage capacity of EEPROM?
A: EEPROM is designed for storing relatively small amounts of data compared to other memory types, making it suitable for configuration settings, calibration data, and small parameter storage in electronic devices.

### Q: How many times can an EEPROM cell be rewritten?
A: Each EEPROM cell has a limited number of write/erase cycles, typically in the range of 10,000 to 100,000 cycles depending on the specific technology and manufacturer.

## Why It Matters
EEPROM represents a critical advancement in memory technology by combining the nonvolatile nature of ROM with the upgradability of RAM without requiring physical chip replacement. This capability enables devices to store calibration data, configuration settings, firmware updates, and other small but essential data that must persist between power cycles while allowing for occasional modifications. EEPROM technology is fundamental to modern computing devices, microcontrollers, embedded systems, and consumer electronics, enabling manufacturers to fix bugs, add features, and customize products after deployment without hardware changes.

## Notable For
- Electrically erasable without requiring UV light exposure (unlike EPROM)
- Allows byte-level erasure and reprogramming rather than requiring entire block erasure
- Maintains data integrity without power consumption (nonvolatile)
- Used extensively for small data storage needs in computers and microcontrollers
- Provides a middle ground between permanent ROM and volatile RAM memory types

## Body

### Technology
EEPROM consists of arrays of floating-gate transistors that trap electrical charge to represent stored data. The floating gate is completely surrounded by insulating material, allowing charge to remain trapped for extended periods without power. This enables the nonvolatile characteristic of the memory while allowing for electrical erasure and reprogramming through special programming signals applied to the control gate.

### Functionality
Unlike EPROM (which requires UV light for erasure) or traditional ROM (which is permanently programmed), EEPROM allows individual bytes to be erased and reprogrammed in-circuit. This is achieved by applying specific voltage sequences to the memory cells, which either adds or removes electrons from the floating gate. The memory retains this state without power, providing both persistence and modifiability.

### Applications
EEPROM is commonly used in computers and microcontrollers for storing relatively small amounts of data that need to persist between power cycles but may occasionally require updating. Typical applications include storing device configuration parameters, calibration data, security keys, small firmware updates, and user settings in various electronic devices from consumer electronics to industrial systems.

### Comparisons
EEPROM differs from similar memory types in several key ways. It is distinct from EPROM in that it can be electrically erased rather than requiring UV light exposure. It differs from flash memory in that it typically allows for byte-level erasure and reprogramming rather than requiring block-level operations. It also differs from traditional ROM which is permanently programmed during manufacturing and cannot be modified after fabrication.

## References

1. Freebase Data Dumps. 2013
2. KBpedia
3. [OpenAlex](https://docs.openalex.org/download-snapshot/snapshot-data-format)