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Serial EEPROM Overview

Our serial EEPROM products are compatible with five serial bus types and support densities that range from 128 bits up to 4 Mbits. These bus types include the standard two-wire I2C, three-wire Microwire, four-wire SPI, along with proprietary single-wire and UNI/O buses. Almost all applications can be supported with operating voltages ranging from 1.5V up to 5.5V and operating temperature ranging from -40°C to 150°C.

We continue to offer new serial EEPROM innovations. Our single-wire devices require just one I/O pin to interface with a microcontroller or another single-wire chip. These are ideal for adding verification, usage record and counterfeit protection to your devices. Additionally, we offer a family of MAC address chips, each of which is pre-programmed with unique EUI-48™ and EUI-64™ node addresses. We also manufacture Unique ID EEPROMs that are pre-programmed with a 32-, 48-, 64- or 128-bit serial number to provide device identification and tracking.

What is EEPROM?

This short three-minute video will give you a high-level overview of EEPROM including what it is, why it sells, when to choose it and when not to choose it.

How to Select Your Serial EEPROM

When choosing a serial EEPROM, there is a balancing act between cost and density, but the system software will usually drive this requirement. Usually the amount of memory required to complete a project is estimated before the design is completed. The final density purchased is usually 50% larger to allow for future growth.

To better illustrate the process of selecting a specific EEPROM device, here is an example of the types of questions that come up in the design phase:

  • Does the microcontroller have a programmable serial port that can support I2C, SPI, Microwire or UNI/O® serial buses?
  • How many spare I/O ports on the microcontroller are available for use by the EEPROM?
    • Is your microcontroller pin limited?
    • Is it cheaper to switch to a bigger microcontroller or reduce the I/O ports required to interface with the serial EEPROM?
    • Do you need to use less I/O pins with memory on the microcontroller to free up the extra I/O pins for other applications?
  • Are there any other peripherals in the system design that use a serial interface such as I2C, SPI or Microwire?
    • If no serial ports are available, will the serial interface be emulated by bit banging several I/O ports?
  • How much memory will be required to complete the project and will it be necessary to upgrade to a larger memory size in the future?
    • If more memory is needed, will a larger package impact the design?
    • If more memory is needed will cascading serial EEPROMs be a viable option
  • Is the bus speed known so that a bus type can be selected?
  • If there is a limitation of I/O ports, will the slower speeds of the I2C or UNI/O bus meet the system requirements since they use the fewest I/O ports, two and one respectively?
  • Are there any space constraints in the application that dictate a smaller package or die/wafer?
  • Is there a minimum or maximum voltage or operating temperature requirement?

In many cases, the application notes and technical briefs you read will point you directly to the part you should use. Finally, contact your local Microchip Sales Office and discuss your findings with one of our knowledgeable sales staff or Field Applications Engineers (FAEs). They would be happy to help you with your Serial EEPROM selection.

I2C Serial EEPROM Products by Density

SPI Serial EEPROM Products by Density

Microwire Serial EEPROM Products by Density

UNI/O Bus Serial EEPROM Products by Density

Single-Wire Serial EEPROM Products by Density

Pre-Programmed MAC Address and Unique ID EEPROMs

Need a MAC address but don’t want to buy in bulk? Or do you maybe need a generic unique ID? Microchip makes serialization easy with pre-programmed EEPROMs including IEEE EUI-48™ and EUI-64™ addresses and unique 32-bit and 128-bit Microchip-defined serial numbers.


Do you have a space-constrained application? Or are you looking to integrate EEPROM memory into your module? These tiny 4-ball Wafer Level Chip Scale Package (WLCSP) EEPROMs will fit on the tip of your pen. They are ideal for applications where tiny matters, including smartphones, high-frequency cable ends, cameras, handheld and medical devices. Advanced features like software write protection and configurable hardware addressing allow full I2C functionality while only requiring four physical connections.

Single-Wire and UNI/O Bus EEPROMs

Want to learn more about our innovative communication buses that use just one pin to interface with a microcontroller (MCU)? Discover how to reduce the number of pins needed for your design with our single-wire and UNI/O Bus EEPROMs.


We offer JEDEC-compliant Serial Presence Detect (SPD) EEPROMs for use in DRAM Dual Inline Memory Modules (DIMM). These include software write protection features for the lower 128 bytes of the EEPROM that can be made permanent.

Development Tools

Serial EEPROM PIM PICtail™ Pack

Part number: AC243003

The Serial EEPROM PIM PICtail Modules are a series of boards designed around Microchip Serial EEPROM devices. The boards are designed to interface with the PICtail Plus connector as well as the MPLAB® Starter Kit for Serial Memory Products and the PICkit™ 4, allowing you to get started right out of the box.

MPLAB Starter Kit for Memory Products

Part Number: DV243003

Designers of Serial EEPROM applications can enjoy the increased productivity, reduced time to market and rock-solid design that only a well thought out development system can provide. Microchip's MPLAB Starter Kit for Serial Memory Products includes everything necessary to quickly develop a robust and reliable Serial EEPROM design, and greatly reduces the time required for system integration.

Total Endurance™ Software

Part Number: TotalEnduranceSoftware

Microchip's Total Endurance Software Disk provides electronic systems designers with unprecedented visibility into Serial EEPROM-based applications. Now designers can describe their system to an advanced mathematical model (with a very friendly human interface) which will then predict the performance and reliability of the Serial EEPROM within that environment. Design trade-off analysis that formerly consumed days or weeks can now be accomplished in minutes with a level of accuracy that delivers a truly robust design.


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Getting Started

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Serial EEPROM Cross Reference Guide Download

Memory Product Comparison

  Explore Products Explore Products Explore Products Explore Products Explore Products Explore Products  Explore Products Explore Products
Density 128 bit - 4 Mb 64 Kb - 1 Mb 256 Kb - 8 Mb 512 Kb - 64 Mb 1 - 64 Mb 64 Kb - 1 Mb 512 Kb - 1 Mb 4 Kb - 1 Mb
Clock Frequency 0.4 - 20 MHz 70 ns 45 ns 20 - 104 MHz 55-70 ns 16 - 20 MHz 16 - 20 MHz 1 - 66 MHz
Cost/Bit High High High Low Low Medium Medium Medium
Read Times Medium Fast Fast Medium Fast Medium Medium Medium
Write Times Medium Fast N/A Medium Fast Instantaneous Instantaneous Instantaneous
Pin Count 2 to 8 pins 28 and 32 pins 28 to 44 pins 8 pins 32 and 48 pins 8 pins 8 pins 8 pins
Data Retention 200+ Years 10 Years 10 Years 100+ Years 100+ Years Volatile 20+ Years
(with battery)
100+ Years
Typ. Standby Current 1 µA 200 µA 100 µA ~15 µA ~30 µA ~4 µA ~4 µA ~40 µA
Voltage 1.7 V - 5.5V 2.7V,
1.65V - 1.95V,
2.7V - 3.6V,
2.3V - 3.6V
1.65V - 1.95V,
2.7V - 3.6V,
4.5V - 5.5V
1.65V - 1.95V,
2.5V - 5.5V
2.5V - 5.5V 2.7V - 3.6V,
4.5V - 5.5V
Temperature -55°C to +150°C 1 -55°C to +125°C -40°C to +85°C -40°C to +125°C 1 -40°C to +85°C -40°C to +125°C -40°C to +85°C -40°C to +125°C 1

1. Selected densities