Temperature sensor output is incorrect

[sarang]

Posted on September 06, 2009 at 16:48

Temperature sensor output is incorrect

[st3]

Posted on May 17, 2011 at 13:22

What sensor are you using?

[sarang]

Posted on May 17, 2011 at 13:22

Hello,

We have tested 4-5 boards for temperature sensing and out of them just one shows the accurate value at 0 degree Centigrade. The sensors on these boards work fine at room temperature. The outputs are 11, -40, 10 etc for the boards when they are setup in a temperature chamber at Zero degree centigrade. Is this ADC error or what?

[hbliek]

Posted on May 17, 2011 at 13:22

Are you referring to the internal sensor?

Here's what the manual says about this sensor:

Quote:

The temperature sensor output voltage changes linearly with temperature. The offset of this line varies from chip to chip due to process variation (up to 45 °C from one chip to another).

The internal temperature sensor is more suited to applications that detect temperature variations instead of absolute temperatures. If accurate temperature readings are needed, an external temperature sensor part should be used.