Differential nonlinearity (acronym DNL) is a commonly used measure of performance in digital-to-analog (DAC) and analog-to-digital (ADC) converters.
Ideally, any two adjacent digital codes correspond to output analog voltages that are exactly one Least Significant Bit (LSB) apart.
Differential non-linearity may be expressed in fractional bits or as a percentage of full scale.
A differential non-linearity greater than 1 LSB may lead to a non-monotonic transfer function in a DAC.
Differential linearity is desirable and is inherent to a system such as a single-slope analog-to-digital converter used in nuclear instrumentation.