The adverse effect of noise a constant voltage receives in a semiconductor device capable of data communication through wireless communication is suppressed. Further, communication is performed normally with a constant voltage with less noise even in the case where the amount of received power is large. The semiconductor device includes an input circuit for generating a DC voltage from an AC signal, a circuit for generating a constant voltage lower than the DC voltage, a circuit portion supplied with the constant voltage, a filter, and a feedback circuit for changing impedance with the constant voltage input from the circuit for generating a constant voltage, wherein the filter is electrically connected between the input circuit and the circuit for generating a constant voltage.