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LMT70: Temperature difference with other sensors

Part Number: LMT70


Hi staff

We are evaluating a prototype board on which LMT70 is mounted.
I have a question about the output of the temperature sensor.

<Question content>

Install the prototype board on which LMT70 is mounted at room temperature (about 25℃).
A thermocouple is attached to the surface of the board near the temperature sensor,
and the output of each sensor (after temperature conversion) is compared.

The temperature of the LMT70 is about 3℃ lower than other temperature sensors.
(Temperature sensor input voltage 3.3V)

The temperature sensor is not in contact with other parts.
In addition, we do not perform resin molding.
Even if you raise the temperature, the temperature difference is the same.

Please give me a hint as to why it is 3 ℃ lower than other temperature sensors.

best regards
cafain

  • Dear Cafain - 

    Thermocouples vary in tolerance based on their type, many are in the +/-1.5 to 2C range at room temperatures (E, J, K, N), whereas the LMT70 is +/-0.36C over a wide temperature range. Either the thermocouple is off, or you may need to look into your conversion of the output voltage to temperature. In the datasheet for the LMT70, in section 9, are the transfer functions to reference. You may also benefit from placing the units in an oil bath or controlled temperature chamber, with a high precision reference that is exceeding or matching the LMT70 accuracy.