Resolution

The entire input voltage range (0V to V_REF) is divided into a number of sub-ranges called Step. Each step is assigned a single output digital code. A step is also called LSB (least significant bits) and the number of such steps is usually in powers of two (2ⁿ). Here, n is called the Resolution of the ADC and 2ⁿ provides the step count. For a specific V_REF, the step size is determined by the resolution (V_REF / 2ⁿ).

For example, an ADC with Resolution = 3-bits and V_REF = 2V, total number of steps are 8 and the step size is 250mV.