33.4.3.1 13-bit Mode Operation

When 13-bit mode is selected, the ADC extends its resolution and input range by utilizing a differential conversion scheme for both single-ended and differential measurements. For differential mode, the ADC outputs a signed 13-bit result, representing the voltage difference between the positive and negative inputs, with a range from -4096 to +4095. For single-ended measurements, the ADC internally configures itself as a differential converter, assigning the selected reference voltage (V_REF) to the negative input. The output is formatted as an unsigned 13-bit value, shifting the range from -4096 to +4096 to 0 to 8191. This corresponds to an input voltage range of 0V to 2×V_REF. This effectively doubles the measurable voltage span compared to standard single-ended operation.

The graphs below show 13-bit operation in single-ended mode. The graph to the left shows a standard differential measurement, where the result is determined by the difference between the positive and negative inputs. The middle graph demonstrates how the measurement changes when V_REF is assigned to the negative input. Finally, the graph on the right displays the output of the 13-bit single-ended conversion, where the result is shifted to output only positive numbers.