Calibration method for precision signal chain linearity

A method of operating an analog-to-digital converter (ADC) circuit, the method comprising:

• applying, in a calibration mode, multiple input voltages to the input of the ADC circuit, wherein the multiple input voltages are generated using a reference voltage;
• converting the multiple input voltages to first digital values using a first ADC acquisition time during the calibration mode;
• converting the same multiple input voltages to second digital values using a second ADC acquisition time shorter than the first ADC acquisition time during the calibration mode;
• determining calibration information for the ADC circuit using the first digital values of the first longer ADC acquisition time and the second digital values of the second shorter ADC acquisition time;
• performing analog-to-digital (A/D) conversions by the ADC circuit in a non-calibration mode using the reference voltage;
• and
• scaling (A/D) conversion results of the ADC circuit in a non-calibration mode using the calibration information.

A non-transitory computer readable storage medium including instructions that, when performed by a controller processor of a calibration device coupled to an analog-to-digital converter (ADC) circuit, causes the calibration device to perform steps comprising:

• applying, in a calibration mode, multiple differential input voltages to an input of the ADC circuit, wherein the multiple input voltages are generated using a reference voltage and analog-to-digital (A/D) conversions are performed by the ADC circuit using the reference voltage;
• receiving first digital values from the ADC circuit representing A/D conversions of the multiple differential input voltages using a first ADC sample time during the calibration mode;
• receiving second digital values from the ADC circuit representing A/D conversions of the same multiple differential input voltages using a second ADC sample time shorter than the first ADC sample time during the calibration mode;
• determining calibration information for the ADC circuit using the first digital values of the first ADC sample time and the second digital values of the second shorter ADC sample time;
• and
• providing the calibration information to the ADC circuit for subsequent A/D conversions performed in a non-calibration mode.