Semiconductor device and wireless communication device

A semiconductor device comprising:

• a plurality of constant current circuits each including a first transistor, a second transistor, and a third transistor,
• wherein a gate of the first transistor is electrically connected to one of a source and a drain of the third transistor,
• wherein a gate of the second transistor is electrically connected to a first wiring which transmits a digital signal,
• wherein the other of the source and the drain of the third transistor is electrically connected to a second wiring which transmits an analog potential,
• wherein a first current corresponding to the analog potential flows through the first transistor,
• wherein the second transistor is configured to control the first current which flows through the first transistor, in response to the digital signal, and
• wherein the first transistor, the second transistor, and the third transistor each include a semiconductor layer including an oxide semiconductor in a channel formation region.