Belles Ondes : Creative Engineering

Audio performance of a DAC versus its bit resolution can be easily elaborated with simple math handling.

First, let's consider that the DAC maximum output level is 0dB: as a consequence, the DAC quantum is the opposite of the total DAC range, and its value expressed in percentage is equivalent to the accuracy of the DAC. This accuracy by extension is the basic accuracy expected from the resistors of a R2R DAC. Moreover, expressing the quantum in terms of dB gives a good indication on the dynamic range achieved by the corresponding DAC.

Results are summarised in the figure below :

A 1 bit DAC can output only 0 or Vcc. Its accuracy is obviously poor (50% !) and its dynamic range is … none !