A data strobe signal output driver includes a trigger block, a predriver block, and a main driver block. The trigger block is configured to receive a first signal, a second signal, a first clock and a second clock, and to output a predrive signal based thereon. The predriver block is configured to receive the predrive signal, a driver off signal and a termination enable signal, and to output a first main drive signal and a second main drive signal based thereon. The main driver block is configured to output a data strobe signal based on the first and second main drive signals.