The present invention is intended to provide an A/D converter making it possible to reduce the power consumption of an output interface. The A/D converter includes an output current value designation register that holds a value sent from an upper-level unit, and an output current value designation circuit that controls a constant current source, which supplies a constant current to a low-voltage differential signal output circuit, according to the value held in the output current value designation register so as to designate an output current value.