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What Is EEPROM and How Does it Work?

When people use computers and laptops, they don’t often consider what components are inside and how they make the device work. It’s essential for individuals involved in building tech to understand what every part of the machine does and how it affects the end-user. 

PC memory and specifically EEPROM is one such crucial element that is required for ideal functioning.

What is EEPROM?

EEPROM is short for “electrically erasable programmable read-only memory.” It’s a flash drive memory device designed to retain the stored information even when the power is off. 

The chip allows developers to write and program the IC many times. This will enable it to act as EPROM, a UV erasable programming ROM. It’s used primarily in computers and laptops. The board is also useful when integrated into microcontrollers for smart cards and remote keyless systems as non-volatile storage.

Considerations of EEPROM

EEPROM offers excellent performance and capabilities, here is a brief overview of EEPROM properties:

  • The chip can be reprogrammed an infinite number of times.
  • Data deletion is immediate using electricity.
  • It’s programmable without removing it from the machine.
  • Additional equipment isn’t required to change the contents of the chip.
  • Data can be erased on a byte-by-byte basis
  • To erase, read, or write the data into EEPROM requires two different voltages.
  • The chip has a limited retention time.
  • Its price when compared to other memory options.
  • Executing changes to the serial unit takes time.

EEPROM Memory Types

Within the EEPROM memory range of devices, two main types are available. The way that the unit operates depends on its design and electrical interface.

Serial EEPROM Memory

This type of chip, also known as E2PROMs, is more challenging to operate because fewer pins mean that operations must be performed serially. Since the data is transferred in a serial sequence, it also makes this type slower than the parallel units. 

There are several common interface types:

  • SPI
  • Microwire
  • I2C
  • 1-Wire
  • UNI/O

These require between one and four control indicators for operation. 

Parallel EEPROM Memory

These types of devices usually have an 8-bit wide bus. Using the bus in parallel enables it to cover the complete memory of many smaller control programs. Typically devices have pins for protecting against choose and write functions. 

Also included are some microcontrollers, which are used to have an integrated parallel EEPROM for software storage. The chip works faster than that of the serial units and the operation is more straightforward. A disadvantage is that this type is larger because of the increased pin count. 

EEPROM Memory Failure Issues

One of the most significant drawbacks of the chip is its lack of overall reliability. This has led to a decrease in their use as other improved memory types appear on the market. Users need to be aware of the two main ways that EEPROM devices can fail.

Data Retention Time

Any device’s data retention timespan is critical, mainly if it contains the software required for electronic equipment operation. In a desktop computer, this could hold the boot software, which the PC won’t work without. 

The retention limit on EEPROM is limited. It’s because during storage the electrons injected into the floating gate could move through the insulation chamber, which isn’t stable. It causes any charge which has settled in the gateway to vanish and the memory cell reverting to its blank state. 

The time frame for this to occur is very long, with guarantees from manufacturers spanning up to 10 years. However, other factors can affect longevity, such as temperature fluctuations. 

Data Endurance

It’s been found that during rewrite procedures of the EEPROM device, the oxide within the floating gate transistors of the memory cell gradually accumulates trapped electrons. The electric field surrounding these particles combines with that of the required ones.  

The result is a state where there aren’t any electrons in the entrance, but it still has a residual field. This increases as more elements become trapped. The situation escalates to the point where it’s no longer possible to differentiate between the zero state threshold. 

The cell then gets stuck in programming mode. Even though manufacturers guarantee a minimum of 10 million rewrite cycles, the memory chip degrades and can result in data loss over time. 

Final Thoughts

Modern technology is impressive and allows us to perform our daily duties with ease. However, even the best tech has its limitations. EEPROM enables users to manipulate data using electrical impulses and retains information when the power is off. 

The chip has its benefits but is considered to be in decline as it makes room for more modern innovations such as Flash. Manufacturers will likely phase out this type of device as new machines are built for faster and more reliable memory chips.