AD7689 internal temperature sensor

Document created by analog-archivist Employee on Feb 23, 2016Last modified by analog-archivist Employee on Feb 23, 2016
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I would like to know the conversion method of the temperature measurement using
the internal temperature sensor in the AD7689.

I have measured the folowing data:
at -40 (cell) -> C73
at +80 (cel)  -> 140C

Using ext Vref  4.096, 16 bit data out

Can you please tell me the conversion formula? (volts to temp)

 

The AD7689 temp sensor conversions are forced to be single-ended conversions
referenced to GND (unipolar) and are therefore straight binary. This temp
sensor output is typical (283 mV @ 25 ̊C) and not trimmed to be absolutely
accurate and hence not a guaranteed spec and it changes as the temp increases
of decreases. For 4.096V reference, the temp sensor output would be -
(4.096V/65536)*output code that you read from the ADC and it changes as the
temp increases of decreases.

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