A sensor device includes an A/D converter including an adder that computes a difference between an analog input signal and a predicted value, the adder includes a capacitive adder defined by a series circuit including a capacitive charge output device and a capacitor. A capacitive component in the charge output device defines a portion of the capacitance of the capacitive adder. A digital prediction filter generates the predicted value based on an output from a quantizer. The capacitive adder computes the difference between the analog input signal from the charge output device and the predicted value. The quantizer quantizes and encodes the difference. The A/D converter performs a Δ modulation on the analog input signal which is converted into a digital signal.