US Patent 11984904 Analog-to-digital converter (ADC) having calibration

An analog-to-digital converter (ADC) includes a digital-to-analog converter (DAC) and a comparator having a first input coupled to receive an output voltage of the DAC, a second input, and a comparison output. The ADC also includes successive-approximation-register (SAR) circuitry having an input to receive the comparison output, and an output to provide an uncalibrated digital value. The DAC includes a Most Significant Bits (MSBs) sub-DAC including a set of MSB DAC elements and a Least Significant Bits (LSBs) sub-DAC including a set of LSB DAC elements. The ADC also includes calibration circuitry which receives the uncalibrated digital value and applies one or more calibration values to the uncalibrated digital value to obtain a calibrated digital value. The calibration circuitry obtains a calibration value for each MSB DAC element using the set of LSB DAC elements, the termination element, and at least one of the one or more redundant DAC elements.