Introduction
EEPROM (Electrically Erasable Programmable Read-Only Memory) is a type of non-volatile memory commonly used in embedded systems. It is used to store configuration data, such as calibration values, serial numbers, and user settings, that need to be retained even when power is removed from the system.
There are two types of EEPROM available in the market, Internal and External. In this post, we will compare both types of EEPROM to help you make an informed decision about which one to use in your next embedded system.
Internal EEPROM
Internal EEPROM is integrated into the microcontroller chip itself. As a result, it has some advantages over external EEPROM.
Advantages of Internal EEPROM
- Faster access time
- Lower power consumption
- No additional PCB space required
- Easier to design and manufacture
Disadvantages of Internal EEPROM
- Limited capacity
- EEPROM endurance (the number of write/erase cycles) is lower than flash memory
- Higher cost per bit compared to external EEPROM
External EEPROM
External EEPROM is a standalone chip that is connected to the microcontroller chip via a serial interface such as I2C or SPI.
Advantages of External EEPROM
- Larger capacity
- Lower cost per bit compared to internal EEPROM
- Higher EEPROM endurance than internal EEPROM
Disadvantages of External EEPROM
- Slower access time
- Higher power consumption
- Additional PCB space required
- More challenging to design and manufacture
Comparison
Here is a side-by-side comparison of internal and external EEPROM based on the advantages and disadvantages mentioned above.
| Criteria | Internal EEPROM | External EEPROM |
|---|---|---|
| Capacity | Lower (< 4 KB) | Higher (>8 KB) |
| Access time | Faster | Slower |
| Power consumption | Lower | Higher |
| PCB space | No additional | Additional |
| Cost per bit | Higher | Lower |
| EEPROM endurance | Lower | Higher |
It is essential to note that the selection between internal and external EEPROM depends on your project's specific requirements.
Conclusion
As we can see, both internal and external EEPROM have their advantages and disadvantages. The choice between them primarily depends on the project's specific requirements. For smaller applications, where cost and PCB space are critical, internal EEPROM might be a better option. For larger applications, where higher capacity and endurance are essential, external EEPROM might be a better choice.