1.i am new to pH sensing circuits. I have used cn0326 evaluation boards for pH measurements. However I want to squeeze a little morE accuracy out of the adc. in the circuit, the reference and the bias voltage are generated from IOUT2 and a precision 5K resistor. According to the data sheet, Iout2 has an initial tolerance of 5%. Instead of using iout2 and precision 5k resistor combination , should I use a precision voltage reference to generate the reference and the bias voltage? if so, do you have any suggestions about which reference to pick?
2. Any other suggestions to increase resolution?
thanks in advance.