STM32 SAR ADC internal structure

The ADC in STM32x microcontrollers uses the SAR (successive approximation register) principle,

by which the conversion is performed in several steps.

The number of conversion steps is equal to the number of bits in the ADC converter.

Each step is driven by the ADC clock.

Each ADC clock produces one bit from result to output.

ADC internal design is a switched-capacitor type.

The following figures (Figure 1 to Figure 6) explain the principle of ADC operation.

The example given below shows only the first steps of approximation

but the process continues till the LSB is reached.