Semiconductor device

A semiconductor device includes: a clock generator generating a first internal clock signal based on an external clock signal; a clock divider generating second and third internal clock signals based on the first internal clock signal and including an edge adjustor adjusting a timing of one of rising and falling edges of the third internal clock signal, an adjustment information holder supplying an edge adjustment signal to the edge adjustor, and a data strobe generator receiving the second and third internal clock signals to generate a first data strobe signal based on the second internal clock signal, and a second data strobe signal with a phase different from that of the first data strobe signal, based on the third internal clock signal. The edge adjustor adjusts the timing of at least one of the rising and falling edges of the third internal clock signal based on the edge adjustment signal.