The calibration of a DAC using differential linearity measurements

The differential linearity adjustment procedure offers an accurate method of digital-to-analog converter (DAC) adjustment with only modest accuracy in the instrumentation. The author shows that the worst case error in linearity due to a differential linearity error (DLE) of e in the upper N bits is bounded by Ne/3. Self-heating effects and output drive asymmetry can cause superposition errors which also degrade the linearity of the DAC. The effect of the resolution of the instrumentation on the final gain adjustment is shown to increase exponentially with the number of bits corrected.