PURPOSE: An output driver is provided to control the slew rate of an output waveform by making a turn-on time of a pull up and pull down transistor different. CONSTITUTION: A plurality of driving transistors(410) are connected in parallel with each other. A plurality of driving transistors drives an output terminal. A body bias supply unit(420) provides a body bias to a plurality of driving transistors. The body bias supply unit the body bias having at least two levels.
