A semiconductor device includes first and second chips in a package. A first pad is on the first chip and electrically connected to a node between a power supply pad and a ground pad on the first chip. Second and third pads are on the second chip. An internal wiring connects the first pad to the second pad within the package. A power circuit on the semiconductor chip configured to supply a current to the second pad. A switch is on the second chip between the second pad and the power supply circuit to connect or disconnect the second pad from the power circuit. A control circuit is on the second chip and configured to output a first signal for the switch in response to a test signal supplied to the third pad and a second signal to the power circuit to cause the power circuit to output current.