LM35: Negative temperature calculation

Srikanth Kacchu1

Part Number: LM35

As per the datasheet specification, LM35CZ senses from -40 to 110 deg Celsius. If the temperature is negative, whether the output of the sensor is negative as per transfer function?

Eg: If Temp = -20deg C

Then VOUT = 10mV / deg C * (-20) = 200mV

over 4 years ago

0 Jalen Tate89 over 4 years ago

TI__Genius 9675 points

Hi Srikanth,

If you'd like to use LM35 for negative temperature readings, you need to use it in configuration as below. Vout will follow as shown in below screen capture.

Jalen

0 Srikanth Kacchu1 over 4 years ago in reply to Jalen Tate89

Expert 1185 points

Hi Jalen

You mean circuit implementation will change for -ve temperature monitoring but the transfer will still remain the same?

Regards

Srikanth Kacchu

0 Jalen Tate89 over 4 years ago in reply to Srikanth Kacchu1

TI__Genius 9675 points

Srikanth,

Yes that is correct. You essentially need to be able to pull the voltage below ground (the negative rail) in order to output voltage corresponding to negative temperatures.

Jalen

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LM35: Negative temperature calculation