The present invention provides an integrated circuit having a better ESD protection capability and capable of reducing a circuit layout area. The integrated circuit comprises: an internal circuit, a first pad, and at least a first impedance matching unit. The first impedance matching unit is coupled between the internal circuit and the first pad, and the first impedance matching unit comprises: a first switch unit and a first resistance unit. The first switch unit is coupled to the internal circuit, and the first resistance unit is coupled between the first switch unit and the first pad, wherein the first resistance unit has a first terminal and a second terminal. The first terminal is directly electrically connected to the first pad and the second terminal is coupled to the first switch unit.