Provided is a semiconductor device capable of controlling an on-die-termination (ODT) circuit and an off-chip-driver (OCD) circuit and a control method used by the semiconductor device. The semiconductor device includes a control code generation unit generating a control code in response to a control signal, an addition unit adding an adjustment code to the control code to produce an adjusted control code, and an ODT circuit, wherein an impedance of the ODT circuit is adjusted in response to the adjusted control code. The semiconductor device can adjust the control code more precisely by adding or subtracting the adjustment code to or from the control code. Accordingly, the impedance of an OCD circuit or ODT circuit can be adjusted more precisely.