A device, comprising an output terminal; an output circuit coupled to the output terminal and having an adjustable impedance; and an impedance adjustment circuit adjusting stepwise the adjustable impedance so as to head toward a first reference impedance. The impedance adjustment circuit changes the adjustable impedance by a first amount when the adjustable impedance is within a first range, and changes the adjustable impedance by a second amount when the adjustable impedance is out of the first range. The first amount is smaller than the second amount.