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Original question:

TMP119: NIST traceability and the contents of EEPROM1 and EEPROM3

TMP119: TMP119: NIST traceability and the contents of EEPROM1, EEPROM2, EEPROM3, and device ID

Lawrence Adelson
Prodigy 30 points
Part Number: TMP119

Tool/software:

The data sheet says the three eeproms are available as scratch pads, and that they are related to NIST traceability.

A similar thread reply says that they can be decoded to get various items, such as manufacturer, part number and revision.

what is the decoding protocol? i.e. which bits mean what in the three eeproms?

What is the significance or the various bits in the device ID?

does every device have a unique device ID?

does every device have a unique traceability to NIST?

if the three eeproms are overwritten, is the device still traceable to NIST?

If the device is calibrated at manufacture, why is there an offset location?

thank you

  • 0
    TI__Expert 3175 points

    Hi Lawrence,

    • "What is the decoding protocol? i.e. which bits mean what in the three eeproms?"
      • During production, a "Unique ID" is programmed into the TMP119's general-purpose EEPROM. The Unique ID can be decoded to get information such as lot #, wafer #, wafer coordinates, and other info. We do not typically post the decoding protocol in the datasheet. Is this information necessary for your application? 
    • "What is the significance or the various bits in the device ID?"
      • The "Device ID" is stored in register address 0x0F. The code signifies the product type and revision. This is NOT the Unique ID. The readback value is 0x2117. 
    • "Does every device have a unique device ID?"
      • Every individual device has its own "Unique ID". 
      • All TMP119's have the same "Device ID". 
    • "Does every device have a unique traceability to NIST?"
      • Yes. 100% of TMP119 units are tested on a production setup that is NIST traceable and verified with equipment that is calibrated to ISO/IEC 17025 accredited standards. 
    • "If the three eeproms are overwritten, is the device still traceable to NIST?"
      • To maintain NIST traceability, do not delete or reprogram the general-purpose EEPROM[4:1] locations. 
    • "If the device is calibrated at manufacture, why is there an offset location?"
      • The device's temperature accuracy is calibrated at production and specified in the datasheet Electrical Characteristics table. So you are correct in saying that the device itself should not need any recalibration.
      • A digital offset (register 0x07) may be applied for system correction or calibration. This may be needed depending on the application. If it is not needed, you can leave it as 0. 

    Best,

    Sakeenah

  • 0 in reply to Sakeenah Khan
    Prodigy 30 points

    the decoding protocol is not necessary, but it seems a good thing to know, and one never knows when it may become necessary

    eeprom[4:1] implies 4 (consecutive) eeprom locations. i take this to mean eeprom1 through eeprom3 and the device id.

    thank you

  • 0 in reply to Lawrence Adelson
    TI__Expert 3175 points

    Hi Lawrence, 

    The decoding protocol is considered confidential, and may be disclosed under a NDA on a case-by-case basis. 

    That's right, the 48-bit EEPROM (3 registers) holds the Unique ID, and the Device ID register is read-only. 

    Feel free to open a new e2e with additional questions. Thanks! 

    Sakeenah