One semiconductor device includes a command receiver receiving the command signal to generate a first internal command signal, and a latency control circuit activating a second internal chip select signal after elapse of first cycles of a clock signal since a first internal chip select signal is activated. The latency control circuit activates a second control signal when the chip select signal is maintained in an inactive state during second cycles of the clock signal that is larger than the first cycles. The command receiver is activated based on a first control signal. The first control signal is activated in response to the first internal chip select signal. The first control signal is deactivated in response to the second control signal.