18.2 D/A Resolution

The resolution is the smallest possible change in output voltage. For a 12-bit DAC the resolution is 1/(212), or 1/4096, of the full range of possible output voltages, called the full scale range. This smallest change results from an increase or decrease of 1 in the D/A code, so this change is referred to as 1 least significant bit (1 LSB ). The value of this LSB is calculated as follows:

12-bit DAC: 1 LSB = Full scale range / 4096

16-bit DAC: 1 LSB = Full scale range / 65536

Example for 12-bit DAC:

For output range = unipolar 0-10V, Full scale range = 10V – 0V = 10V, so 1 LSB = 10V / 4096 = 2.44mV.

For output range = bipolar ±10V, Full scale range = 10V – (-10V) = 20V, so 1 LSB = 20V / 4096 = 4.88mV.