EEPROM stands for electrically erasable programmable read-only memory. It is a non-volatile flash memory device, that is, stored information is retained when the power is removed. It generally offers excellent capabilities and performance. In EEPROM we can write and program the IC for many times and these are acting as EPROM (UV erasable programming ROM).
However an EEPROM need not be taken out of the computer or electronic device of which it is part when a new program or information or data needs to be written on it. Particular customizing might be finished to an EEPROM chip.
The client/user can change the quality of certain units without expecting to erase the programming on different cells. Consequently, areas of data might be erased and replaced without expecting to adjust whatever rest of the chip programming. Data saved in an EEPROM chip is permanent, until the client chooses to delete and replace the data that it contains. The information saved in an EEPROM chip is not lost even when power is turned off. Here only one external power supply device is used . Write and erase operation are performed on byte basis.
There are many types of EEPROM devices available, but one of the most commonly used EEPROM families is 24CXX series devices such as 24C02, 24C04, 24C08 and etc. These all are have same features but only difference is in its memory.
Low and standard voltage operation (100 kHz (1.8V) and 400 kHz (2.7V, 5V) compatibility)
Schmitt trigger, filtered inputs for noise suppression
Internally Organized 128 x 8 (1K), 256 x 8 (2K), 512 x 8 (4K), 1024 x 8 (8K) or 2048 x 8 (16K)
Automotive devices available
Two-wire serial interface (Two wires are used to read and write data into it)
Bidirectional data transfer protocol
Write protect pin for hardware data protection
8-byte page (1K, 2K), 16-byte page (4K, 8K, 16K) write modes
Partial age writes allowed
Self-timed write cycle
Principle of operation of EEPROM
The EEPROM uses the principle same as that of the UV-EPROM. The electrons which are trapped in a floating gate will modify the characteristics of the cell, so instead of that logic “0” or logic “1” will be stored.
It is a memory device which implements the fewest standards in cell design. Most of the common cells are composed of two transistors. In this the storage transistor has the floating gate that will trap the electrons. Apart from that there is an access transistor which is used in the operation. In EPROM , cell is erased when electrons are removed from the floating gate, whereas in EEPROM , cell is erased when electrons are trapped in the floating cell.