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TMP175: Accuracy and PSR?

Kurumi Hasegawa
Expert 7891 points
Part Number: TMP175

Hi team,

 

I’ve got a question on how to estimate temperature accuracy.

 

The datasheet has Terr and PSR. What PSR: Temperature accuracy(temperature error vs supply) means?

For example, assuming supply voltage is 5V and temp is 50℃, would it be ±0.5℃ typ?

Or, would it be ±0.5℃±0.2*5℃=±(0.5+1)=±6℃ typ?

 

 

Best regards,

Kurumi

  • +1
    TI__Mastermind 43805 points

    Hi Kurumi-san,

    PSR is worst-case error due to supply variation. For example, if data showed that temperature error was +1C at 5.5V, and error was -1C at 2.7V, we would calculate 2C change divided by (5.5-2.7) or 2.8V. ~0.7C/V. We also have to account for temperature variation in our max specs, so we may observe a different supply variation at 125C, or -40C, for example. 

    In production, we remove temperature offset at the 'typical' condition: 3.3V and 25C. 

    The PSR spec can be used to predict error relative to typical condition. For 5V supply, you should use 1.7 to represent the change in voltage from 3.3V. Using the TMP175 at 5V instead of 3.3V can add 0.2*1.7 error typical, and 0.5*1.7 error max. 

    thanks,

    ren

  • 0 in reply to Ren Schackmann
    TI__Expert 7891 points

    Hi Ren,

    I understand, thank you so much for the detailed explanation!

    Best regards,

    Kurumi