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TMP451-Q1: Abnormal temperature detected

Part Number: TMP451-Q1
Other Parts Discussed in Thread: TMP451


Blue is the remote temperature (tmp451), and red is the actual temperature curve,

Random abnormal temperature will appear in remote temperature detection,

What causes it? Do you have any good suggestions?


  • Hi Neal,

    Thank you for your post.

    Based on table 1 in the datasheet, there should be no way for the TMP451 to give you a temperature above 191C. How is the temperature conversion being done here?

    The TMP451 looks like it is tracking the desired temperature quite well with the exception of those spikes. They could be due to a poor connection, or possibly due to random environmental noise. I would recommend giving the boards a thorough cleaning, and attempting the test in another location to see if the spikes still occur. It would also be worthwhile to visually inspect the solder contacts on your board surrounding the diode and TMP451. 

    Lastly, can you capture the I2C lines on an oscilloscope? A read of the temperature register would be preferable. Massive undershoot like this could be explained by the unintentional swapping of the most significant bit due to noise or I2C timing. 

    Best Regards,
    Brandon Fisher