At the core of every analog-to-digital conversion procedure lies a vital component called a comparator. In each ADC design, one or more comparators are integrated, with more sophisticated designs employing multiple units. The comparator serves as a basic one-bit ADC, taking in two analog voltage inputs and producing a binary output. If the voltage at the positive input surpasses that at the negative input, the comparator generates a digital output of 1. On the other hand, if the voltage at the positive input is lower than that at the negative input, the output is set to a digital 0.

The linearity reference is another critical component shared by all ADCs. During the conversion process, this reference becomes the comparing element against which the input signal is evaluated. The linearity reference has a considerable impact on the ADC's differential and integral nonlinearities. Examples of such references include capacitors in integrating ADCs and digital-to-analog converters (DACs) in successive-approximation ADCs.

Finally, every ADC includes a voltage reference. This reference, which is frequently linked to or part of the linearity reference, determines the ADC's full-scale input range, determining the range of numbers the ADC can reliably understand and convert.