A semiconductor system is provided, which includes a controller configured to output an active command and test mode signals; and a semiconductor device configured to sense and amplify a pair of bit lines by generating a first power control signal of which a pulse width is adjusted in accordance with a combination of the test mode signals during an enable period of an enable signal generated by the active command, receiving a supply of a first power according to the first power control signal, and receiving a supply of a second power according to a second power control signal.