A semiconductor device for reducing an instantaneous voltage drop is provided. The semiconductor device includes a first power line configured to provide a first power supply voltage and a first power transistor connected between the first power line and a first logic transistor. The first power transistor includes a first source or drain connected to the first power line, a gate receiving a power gating control signal, and a second source or drain connected to a first source or drain of the first logic transistor using a shared semiconductor junction.