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TMP236-Q1: Operation range?

Part Number: TMP236-Q1
Other Parts Discussed in Thread: TMP235-Q1, TMP235, TMP236, LM35, TMP61, TMP63, TMP64

Dear TI team,

there is some contradictory information in the datasheet regarding the operation range of the sensor.

In the heading of datasheet there is stated that the operation range is -40 .. 125 °C.

However, the accuracy specified for the range -10 .. 125 °C as well as the info in transfer table specifies also -10 °C as the minimum measurement limit.

So, two questions:

- what is the really operation/measurement range of the TMP236-Q1 sensor?

- why there is contradictory info specified in the datasheet?

Thanks and looking forward to your answer!


Igor Kuksin.

  • Dear Igor - 

    Thanks for posting on E2E!

    the datasheet is not really contradicting itself. The spec table is presented that way so it presents the entire operating range of the part and what will be seen over a smaller range, that results in a same accuracy (+/-2.5C max) as the TMP235-Q1. I think its expected here that if same accuracy is needed at the lower temps, then the TMP235-Q1 should be used. I do see your point about the transfer table being odd that it does not have values in it for below -10C, but if you look at the graph on the front page of the datasheet, it should be clear why they are not present, as if you extrapolate that red line down, you will see that at about -20C the output will go negative (in voltage). Hope that clears it up for you.   


  • Dear Josh,

    Thanks for your answer!

    I also noticed at the graph (Vout vs Ta) that at the temp ~ -20 °C the output will reach the 0 V and goes negative.

    Still, what is not clear and I see contradictory -> please take a look at the header of datasheet (the pic I posted and marked in red rect): the temperature range for TMP236-Q1 specified as grade 1: –40°C to +125°C, right?

    But in the reality the operation range of the TMP236-Q1 is: –10°C to +125°C.

    Do I getting it correctly?



  • Igor - 

    Operating range and accuracy range are not the same thing - the feature you highlighted in red and pointed out means it can operate in the range of -40 to 125C. The orange box highlights the temperature range in which the TMP236-Q1 will be accurate to +/-2.5C. 

  • Dear Josh,

    thanks for answer!

    yes, this is clear, that accuracy and operation range is not the same thing.

    I mean, what is specified as the operation range -40C .. +125C for this sensor -> could not me reached in general.

    Because here, I suppose for temperature sensor the operation range and measurement range is the same thing!

    I can't understand why -40C .. +125C specified as the operation range if the accuracy of the sensor specified at the -10C .. 125C range and at the temperature ~ -20C the output will be already 0V.

    So, the -40C temperature point will never be reached.

    That what I called contradictory information.



  • Igor - 

    TMP23x family has two gain options, as indicated first on the front page of the data sheet. If you require the wider temp range support, you can replace TMP236 directly with TMP235. With regards to the wording of the datasheet, consider operating temperature range to be the range by which the device can be electrically biased (voltage and ground applied) and have no issues.


  • Dear Josh,

    thanks a lot for your help! I got your point - sounds logical :)

    Another short question here. Actually, I use already the TMP235 sensor in my project. And I am considering now to have the different redundant sensor with different output gain/offset.

    The first option was the TMP236 sensor, but it does not fit, because I need to cover the -40C .. +125C measurement range.

    Could you please suggest the another sensor from portfolio, which has similar parameters to the TMP235, but different output gain?



  • Igor, 

    In this case, the TMP236 is the only part in the analog portfolio with that high of a gain and with positive slope, and covering the measurement range you need. Two suggestions to consider -

    1. You could use diode(s) on the negative terminal and lift the part above GND to indicate the negative temperature with a single supply. See example circuit here in the LM35 datasheet, page 16, Figure 18 ==> The issue I see with that might be that because this would offset the slope and possibly rail out on the hot temp side, if your rail on the ADC was 3.9V or less. 

    2. use TMP61, TMP63 or TMP64, these are linear PTCs. You could use this part with an omp amp and control the gain to your exact needs. 

    Let me know if either of these work for you or we need to keep looking for other solutions for you. 

  • Thanks for answer, Josh!

    I'll let you know in case I'll require additional support on this.