SEMICONDUCTOR DEVICE

A microcomputer includes a bus, a CPU (Central Processing Unit) coupled to the bus, a RAM (Random-access Memory) coupled to the bus, and an AD (Analog-to-Digital) converter coupled to the bus. The AD converter includes a switching circuit for switching between an analog signal and a reference potential, a first DA (Digital-to-Analog) converter including a plurality of first capacitors each having one end that can be individually coupled to the switching circuit and the other end coupled to a common output line, one or a plurality of testing capacitors that are dedicated for testing, each having one end to which the reference potential or a potential obtained by dividing the reference potential can be individually inputted, and a control circuit. In a normal mode, the control circuit determines a digital value corresponding to the analog signal, based on the output line.