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TMP236-Q1: What are the tolerances for temperature coefficient Tc?

Ryan Bishop
Prodigy 10 points
Part Number: TMP236-Q1

I am working with TMP236-Q1 parts on a prototype board. According to the datasheet, the typical Tc is 19.5mV. However, measuring the mV output directly on 3 different sensors on temps ranging from 10C to 50C, the coefficient works out to be lower than normal at  19.1mV, 18.9mV and 18.7mV respectively. 

What factors can effect this coefficient? The output is filtered with a 100ohm resistor and 680pF cap as per the datasheet.

Thanks!

  • 0
    TI__Genius 9675 points

    Hi Ryan,

    Can you let me know the detail of how you are calculating the coefficient? Are you measuring the temperature of each sensor from 10°C - 50°C and then averaging the Vout difference to get the coefficient? More info here would be helpful.

    Jalen

  • 0 in reply to Jalen Tate89
    Prodigy 10 points

    Jalen,

    I am measuring the temperature of the sensor and the mV output at 5 degree intervals between 10C and 50C. The sensors are in a temperature chamber. There is no averaging done except what might be done internally in the mV meter. A line fit is then done to the data. For example in this data set, if you  were to plot the points you would find a slope of 18.7mV/C.

    Temperature mV
    10 612
    15 701
    20 793
    25 887
    30 987
    35 1079
    40 1168
    45 1262
    50 1361
  • 0 in reply to Ryan Bishop
    TI__Guru* 91206 points

    Ryan - 

    Please see below  - I made this chart for you to see how the results you are getting are well within spec of the part. (which is +/-2ºC)

    You may want to consider using a calibrated temperature reference in your chamber as well, and positioning it near the DUT as this could reduce some of the potential measurement "error" you are seeing and/or using an oil bath (also with a calibrated reference deployed) for best results accuracy testing.