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TMP235: Accuracy issue/ Wrong output.

Shinu.V.Mathew
Genius 17395 points

Part Number: TMP235

Hi Team,

Customer is using  TMP235A4DCKR and they want to know in  production what was the accuracy of temperature sensor is measured .

They are getting variation more than the datasheet spec.

Can you confirm is the temperature accuracy of each TMP235A4 IC produced is tested in production? 

Please refer below readings.  

TMP235A4
Temperature
Reading

External Thermocouple  reading

Result

21.8

23.8

Fail

21.8

23.7

Fail

21

23.7

Fail

21.4

23.8

Fail

22

24.2

Fail

22.2

24.3

Fail

22.3

24.2

Fail

22.1

24.2

Fail

22.2

24.2

Fail

21.9

24.2

Fail

22.2

24.2

Fail

22.3

24.2

Fail

 Thanks, Shinu. 

  • 0
    TI__Genius 17235 points

    Shinu,

    Yes the TMP235 is tested for temperature accuracy in production at the water level. What sort of temperature environment are you testing these parts? Is it a controlled environment, like an oven? If not, I would recommend a more stable environment and gettnig the reference thermocouple close to the devices. How accurate is the thermocouple? Is the thermocouple placed near other electronic components that could be heating it up more than the TMP235s?

    Thanks

    -Alex Thompson

  • 0
    Prodigy 70 points

    Hi Alex ,

    We are not using Oven to measure temperature and its in production stage ,work in ambient temperature and measure that only. However we do keep a thermal sensor nearby to measure the temperature(Thermocouple only) and we are seeing variation from that only .

    I will share the Part number as well.

    thanks

    Vipin

  • 0 in reply to vipin Mishra
    TI__Genius 12580 points

    Hello Vipin,

    Can you share the part number?

    Best Regards,

    Meredith McKean

  • 0
    Prodigy 20 points

    Hi ,

    From your response i understand every TMP235 produced at TI are tested for temperature accuracy in production, Please correct if any gap in understanding. Can you explain little more about "temperature accuracy in production at the water level"? At what temperature is the IC tested in production and what pass/fail criteria/limits used? I'm thinking if the part is already tested for temperature accuracy during production at TI, want to relax limits during our production as the thermocouple in tester is not very close to the IC.

    Regards,

    Murali Krishna

  • 0 in reply to Meredith McKean
    Prodigy 70 points

    Hi Meredith ,

    We have used DS18B20+  temperature sensor from Maxim as a reference temperature sensor while measuring the temperature from TMP235

  • 0 in reply to vipin Mishra
    TI__Genius 17235 points

    Murali,

    I apologize for the confusion, my initial response had a typo. I meant to say "temperature accuracy in production at the wafer level", not water level. So yes the TMP235s are tested for temp accuracy in production against calibrated equipment, and the pass/fail criteria are the temperature accuracy limits for TMP235 at a minimum.

    Thanks

    -Alex Thompson

  • 0 in reply to Alex Thompson
    Prodigy 20 points

    Thanks Alex for the confirmation.