The present invention provides a Charge Share SAR ADC with which it is possible to raise the order of noise shaping.　This sequential-comparison-type AD converter comprises a first-polarity first capacitor, a first-polarity second capacitor, a first-polarity third capacitor, a second-polarity first capacitor, a second-polarity second capacitor, a second-polarity third capacitor, an integrator amplifier, a comparator, and a filter circuit. The integrator amplifier generates a first integrated value and a second integrated value. The comparator compares the first integrated value and the second integrated value, and, on the basis of the comparison result, redistributes a charge accumulated in the first-polarity third capacitor and a charge accumulated in the second-polarity third capacitor to the first-polarity second capacitor or the second-polarity second capacitor. After the redistribution is repeated, the charge accumulated in the first-polarity third capacitor and the charge accumulated in the second-polarity third capacitor are inputted as residual voltage into the filter circuit.
SEQUENTIAL-COMPARISON-TYPE AD CONVERTER, Iot SENSOR, AND BIOLOGICAL SENSOR