Hi,
1.What is the Voltage Reference value of ADS1115-q1 ADC sample?There is no indication in the specification ;
2.What is the logical relationship between Voltage Reference and FSR?
Thanks!
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Hi,
1.What is the Voltage Reference value of ADS1115-q1 ADC sample?There is no indication in the specification ;
2.What is the logical relationship between Voltage Reference and FSR?
Thanks!
Hi Neal,
the ADS1115-Q1 has a very unique voltage reference implementation. You cannot really define what this reference voltage value is.
You could arbitrarily say the reference voltage is 1.024V and then say the PGA offers a gain of 1 for the +/-1.024V FSR setting and a gain of 4 for the +/-0.256V FSR setting.
The only thing that is important in the end is how to convert the conversion result into a voltage. For that you only need to know the FSR setting.
The relationship between differential input voltage (VIN) and conversion result (Code) reads:
Code / 2^16 = VIN / FSR
Let's say you use a FSR = +/-0.256V as in your other post and the decimal output code of the ADC would read 100dec.
That would mean the differential input signal applied to the ADC is:
VIN = 100 / 2^16 x (2 x 0.256V) = 0.78125mV
Regards,