I have an AD7689 that I am using to monitor temperature in addition to voltages. Right now, in a 22C room, I am reading the temperature from the AD7689 to be 2C. Is there a calibration needed?
I am reading my voltages correctly, so the ADC is in good shape. I am getting readings of around 2C for all three AD7689s I have used.
The configuration word being used is 0xB160, that is,
1: overwrite config register
3: read temperature
0: don't care channel
1: full bandwidth
3: ext. ref., int buff, temperature enabled
0: disable sequencer
1: no read back
all shifted up by two.
The value I read from the ADC is then converted to mV referenced to a 3.3 external reference with 65536 bits of resolution. The temperature is then calculated with 25C at 283mV offset by the ADC reading. That is, temperature = 25C + ((reading -283mV)/1mV/C).
Thanks for any help.