An A/D converter includes a first switched capacitor block that charges
and holds charges by connecting each of a first group of capacitors to a
single basic reference voltage at a first timing, and discharges each of
the charges held by the first group of capacitors at a second timing, a
second switched capacitor block that charges and holds each of the
charges discharged by the first group of capacitors respectively in the
second group of capacitors at the second timing, and converts each of the
charges held by the second group of capacitors to a voltage and outputs
the voltages at the first timing, and a quantizer that quantizes an
analog input signal using the plurality of voltages output from the
second switched capacitor block as reference voltages for each level. A
plurality of reference voltages is generated from a single basic
reference voltage, based on different amounts of charges held in the
plurality of capacitors. A high SNR is obtained by supplying the
reference voltages of a quantizer in a multi-bit A/D converter with high
accuracy, and low power consumption operation is possible with simplified
circuitry.