Q
The temperature sensor specification on the only mentions Sensitivity=0.81mV/°C typical. How to calculate the internal temperature of the AD7793 according to this parameter, and what is the specific conversion formula?
A
In bipolar mode:
Temperature (°C) = (conversion – 0x800000) / sensitivity(in codes)
Temperature (°C) = conversion – 0x800000) / 5807
Temperature (K) = Temperature (°C) – 273.15
where:
5807 is the 0.81mv/°C in codes for bipolar mode.
or
Temperature (°C) = (conversion – 0x800000) / ((2^23((sensitivity(mV/°C) / VREF) + 1)) – 0x800000)
Temperature (K) = Temperature (°C) – 273.15
where:
VREF = 1.17V
Sensitivity(mV/°C) = 0.81mV/°C
Conversion = ADC conversion in codes
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In Unipolar mode:
Temperature (°C) = conversion / sensitivity(in codes)
Temperature (°C) = conversion / 11615
Temperature (K) = Temperature (°C) – 273.15
where:
11615 is the 0.81mv/degC in codes for bipolar mode and unipolar mode respectively.
or
Temperature (°C) = conversion / (((2^24)(sensitivity(mV/°C)) / VREF)
Temperature (K) = Temperature (°C) – 273.15
where:
VREF = 1.17V
Sensitivity(mV/°C) = 0.81mV/°C
Conversion = ADC conversion in codes