https://devzone.nordicsemi.com/f/nordic-q-a/4338/adc-questionHi, are my assumptions below correct? Measuring a (ratiometric to VCC) analog signal and selecting VDD_1_2_PS as the reference selecting AIN_NO_PS or AIN_2_3_PS will not be able to measure full scale. Selecting AIN_1_3_PS with VDD_1_2_PS will giveen-USTelligent Community 13Thu, 06 Nov 2014 12:00:54 GMThttps://devzone.nordicsemi.com/thread/15437?ContentTypeID=1Thu, 06 Nov 2014 12:00:54 GMT137ad170-7792-4731-bb38-c0d22fbe4515:50c0c806-e0fe-4487-a28d-0846b6bf04bbStefan Birnir Sverrisson<p>Hi</p> <p>It is not possible to connect VCC directly to AREF0, because the voltage of the AREF0 signal must be in the range 0.83V-1.3V, see the nRF51822_PS v3.1 table 51.</p> <p>If you have an analog input signal that is ratiometric to VCC and in the range 0V-VCC, then I suspect it is convenient to select VDD 1/3 PS reference and AIN 1/3 PS as the prescaler for the input signal.</p> <p>If you select AIN 1/3 PS adn VDD 1/2 PS for input signal range of 0V-VCC, then you will not utilize the full resolution of the ADC, only 66% of it.</p><div style="clear:both;"></div>