Methods and apparatus to test and compensate multi-channel digital-to-analog converters

A method to test a multi-channel digital-to-analog converter (DAC), comprising:

• applying a test signal to a first DAC channel to generate a first analog representation and a second DAC channel to generate a second analog representation;
• determining a phase relationship between the first and second analog representations;
• determining if the phase relationship is within a tolerance;
• determining the multi-channel DAC is acceptable if the phase relationship is within the tolerance;
• compensating for a phase mismatch if the phase relationship is not within the tolerance;
• and
• storing the phase relationship in response to compensating the test signal and determining the phase relationship is within the tolerance.

A system to test a multi-channel digital-to-analog converter (DAC), comprising:

• a first DAC channel configured to generate a first analog representation based on a first digital input signal;
• a second DAC channel configured to generate a second analog representation based on the first digital input signal;
• a phase compensator configured to generate a compensated analog representation based on the second analog representation to compensate for a phase difference between the first analog representation and the second analog representation;
• an error amplifier configured to generate a difference signal based on the first analog representation and the compensated analog representation;
• a comparator configured to determine whether an amplitude of the difference signal is greater than a threshold;
• a processing unit configured to:
• generate the first digital input signal;
• apply the first digital input signal to the first DAC channel and the second DAC channel;
• generate a second digital input signal by adjusting a phase of the first test input signal in response to the comparator determining the amplitude of the difference signal is greater than the threshold;
• and
• apply the second digital input signal to one of the first DAC channel or the second DAC channel;
• and
• a test system configured to determine whether the DAC is acceptable based on the comparator.