Calibrating a digital-to-analog converter

A system for calibrating a digital-to-analog converter comprising:

• a main digital-to-analog converter (DAC) having a DAC input and a DAC output;
• a calibration digital-to-analog converter (CALDAC) having a CALDAC output coupled to the DAC output for adjusting the DAC output, and having a CALDAC input;
• a lookup table for storing and outputting calibration values, wherein the lookup table has a lookup table input coupled to the DAC input and a lookup table output coupled to the CALDAC input;
• an analog-to-digital converter (ADC) having an ADC output, and an ADC input coupled to the DAC output;
• a waveform generator having a waveform sequence output selectively coupled to the DAC input for providing a waveform sequence to the DAC input and the lookup table input;
• a filter having a filter input coupled to the ADC output, and having a filter output;
• and
• a calibration controller coupled to the waveform generator, the lookup table, and the filter output, wherein the controller is adapted to determine calibration values in the lookup table in response to the waveform sequence and the filter output.

A digital-to-analog converter including calibration comprising:

• a main digital-to-analog converter (DAC) having a DAC input and a DAC output;
• a calibration digital-to-analog converter (CAL DAC) having a CAL DAC output coupled to the DAC output for adjusting the DAC output, and having a CAL DAC input;
• a lookup table for storing and outputting calibration values, wherein the lockup table has a lockup table input coupled to the DAC input and a lookup table output coupled to the CAL DAC input;
• and
• a calibration system for dynamically inputting a waveform sequence into the DAC input and determining the calibration values in response to a distortion at the DAC output corresponding to the waveform sequence, the calibration system further comprising a filter having a filter input coupled to the DAC output, wherein the filter is adapted to pass the distortion at the DAC output corresponding to the waveform sequence.