A semiconductor device is disclosed, which includes first and second power supply pads supplied with first and second power voltages, respectively, a first protection circuit coupled between the first and second power supply pads, and an internal circuit including a first power line and a plurality of transistors electrically coupled to the first power line. The first power line includes first and second portions, and the first portion is electrically connected to the first power supply pad. The device further includes a second protection circuit coupled between the second portion of the first power line and the second power supply pad.