DAC Calibration

Some high speed DAC have options for auto-calibration. Why and when should I use this option?

  • The auto-calibration feature in high speed DAC are aimed at calibrating the current sources of the DAC. This calibration affects the Integral and Differential Non-Linearities of the DAC output which affect DC accuracy - see figures below extracted from AD9117 datasheet

    DC accuracy also affects low frequency AC distortion (<20MHz) but has proven to be less effective at higher Fout frequencies.

    When calibration is needed?

    If application requires DC linearity beyond the typical specification without calibration or low distortion for Fout < 20MHz, DAC calibration is recommended. As current source mismatches changes over temperature, it is also recommended to regularly calibrate the DAC when temperature changes.