The analog inputs have internal ESD diodes that are connected to the analog supplies (AVDD and AVSS). The function of the diodes is to protect the ADC inputs from ESD events. If the input signal exceeds VAVDD by more than 0.3 V or goes below VAVSS by more than –0.3 V, the diodes may conduct. When the diodes conduct, input current flows into the analog inputs through the AVDD or AVSS pins. If an input overvoltage is possible, limit the input current to less than |±10 mA|. In many applications, a resistor in series with the input is sufficient to limit the current. Depending on the application requirements, be aware of the thermal noise of the current limit resistor.