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Factory-Programmed with Digital Serial Numbers, Tracking Numbers, Internet Access Numbers and More


Every EEPROM has its own unique number to give each product you ship individuality for tracking, identification and Internet addressing.

MAC Address

A factory-programmed IEEE EUI-48™ or EUI-64™ address is unique to every IC shipped.

  • EUI-48 and EUI-64 options
  • I2C, SPI, Microwire, UNI/O® bus options
  • Permanent (no overwrite)
  • Globally unique codes

Unique ID

A serial number is factory-programmed and unique to every IC shipped. A tracking number is added by the user and often permanently locked after written.

  • 32-bit, 64-bit, 128-bit, 256-bit serial number on select products
  • 128-bit tracking numbers on select products
  • I2C, SPI, Microwire, UNI/O bus, single-wire options
  • Permanent (no overwrite) serial numbers
  • One-time-programmable (OTP) tracking number (user selected)

EEPROM Programming Services

We also offer EEPROM programming to deliver ready-to-go EEPROMs (any EEPROM – with or without MAC or Unique IDs) for pick-and-place manufacturing. Contact your local sales office to learn more or click here to upload your data and get started.

MAC Address FAQs


Q: Are the MAC IDs in the MAC Address Serial EEPROMs globally unique?
A: Yes, these pre-programmed MAC IDs from Microchip are globally unique. We only use Organizational Unique Identifiers (OUIs) set aside for Microchip by IEEE in these devices. IEEE uses OUIs to ensure different organizations use different MAC IDs that won't overlap.

Q: Are there any volume restrictions?
A: No, you can buy as many (or few) IDs as you need, and these can be purchased as and when needed. Our minimum ordering quantity on tube versions of our devices is as low as one unit through our online store.

Q: Can I tell the contents of the MAC address when I purchase an EUI-48™ or EUI-64™ MAC address EEPROM device? Can I select the range of MAC IDs I need?
A: No, unfortunately we service several thousand customers directly and via distribution worldwide, and this will prove to be a very challenging logistical task to track which IDs reach which customers. As a result, the only way to tell the contents of the ID is by reading the actual EEPROM device directly. We will only ship MAC Address EEPROM devices with Microchip OUIs. The list of possible Microchip OUIs is in the data sheet.

Q: Can I use my EUI-48 MAC address as an EUI-64 address?
A: The pre-programmed EUI-48 node address can easily be encapsulated at the application level to form a globally unique, 64-bit node address for systems utilizing the EUI-64 standard. This is done by adding 0xFFFE between the OUI and the Extension Identifier. For more information about this, refer to the data sheet. We also offer a family of devices with a uniquely pre-programmed EUI-64 node address for use in EUI-64 applications directly without the need for encapsulation, thereby simplifying system software.

Q: I have my own MAC address that I need pre-programmed in an EEPROM. Can Microchip pre-program these for me?
A: No, we are not authorized to sell other OUIs as a Microchip MAC address chip. However, if the volumes are big enough (1M+ units), we can certainly pre-program any data in to our standard EEPROMs and assign custom part numbers to them for your application. Please contact our local sales office to find out more about this service.

Q: If I buy a reel of MAC address EEPROMs, will the devices within a reel be serially programmed?
A: While we serially program these devices on wafer, they are often diced up, tested, packaged and stored in different patterns/combinations, which will disrupt their "serial-ness". As a result, we don't guarantee them to be serially arranged within a reel.

Q: Are there larger memory densities with embedded MAC address?
A: Please contact your local Microchip sales office or email us to inquire about custom options. We also offer a family of NOR Flash with MAC address.

Unique ID Frequently Asked Questions


Q: Are the serial numbers globally unique?
A: No, these pre-programmed serial numbers are only unique to parts ordered by you for this specific product density and commercial part number (CPN). They are unique across all years you order the specific product from Microchip.

Q: How do I determine the embedded serial number?
A: In your programming you read the contents of the serial number from the address location as explained in each data sheet.

Q: If I buy a reel of unique ID EEPROMs, will the devices within a reel be serially programmed?
A: While we serially program these devices on wafer, they are often diced up, tested, packaged and stored in different patterns/combinations, which will disrupt their "serial-ness". As a result, we don't guarantee them to be serially arranged within a reel.

Q: Can tracking numbers by changed anytime, even after the end-product is shipped to the field?
A: See the data sheet for details. Generally, users will enter a tracking number when first assembling the end system and then execute a permanent locking command. After a permanent locking command is given to the EEPROM, the tracking number can never again be altered. Alternately, you may choose to just carefully write protect the tracking number so that field updates can be possible later.

Q: Are there any volume restrictions?
A: No, you can buy as many (or few) ICs as you need over time. Minimum order quantities do apply.