2.2.5 Sample Time
The sample time for each ADC conversion is configurable as a number of half prescaled ADC clock cycles (depending on the prescaler value), allowing the user application to achieve faster or slower sampling depending on the source impedance of the ADC input channels. For applications with high impedance inputs the sample time can be increased to give the ADC an adequate time to sample and convert the input channel.
The resulting sampling time is given by the following equation: