When working with one of the examples from the NXP cookbook, i reliased that the inaccuracy of the ADC channel conversion is very high. In the example code all conversions results for the voltages are shifted 1000 in terms of the final readings. For example when I connecte a 4V on the ADC pin, the voltage result after applying the scaling formula is 5000. All readings suffer from this phenoma. Is there anything that could be done to mitigate such issue.
You can refer to AN12217. Specifically, chapter 3 (Best practices to increase accuracy).
Many factors can cause this, such as unstable VREF. You can also try to add an RC filter at the ADC input to suppress high-frequency noise.
Best regards,
Julián.