This application note describes how to optimize the accuracy of the ST62 family micro-controllers' internal A/D converter. It includes instructions on how to filter analog input noise, how to put the MCU in wait state to minimize power supply noise, and how to make several successive A/D conversions and take an average of the results.
The document provides guidance on maximizing the precision of the A/D converter found in the ST62 family. It highlights that noise on analog inputs, ground lines, and Vcc supply lines can degrade performance, recommending proper decoupling with capacitors.
To further improve accuracy, the text suggests placing the microcontroller in a wait state during conversion to minimize internal noise injection. Additionally, it recommends performing multiple successive conversions and averaging the results for the highest possible precision.
It is desirable to filter out any noise present on the analog input, but also noise present on the ground and Vcc supply lines of the MCU.
Good decoupling must be made with capacitors on the analog input and between Vcc and ground.
It is recommended to put the MCU in wait state while the conversion is in progress to minimize noise injected into Vcc.
It is highly recommended to make several successive A/D conversions and take an average of the results.