An electronic device includes a strobe signal generation circuit and a data output control circuit. The strobe signal generation circuit delays a mode register command by a first predetermined delay period to generate a mode register strobe signal during a mode register read operation. The strobe signal generation circuit adjusts a timing of the mode register strobe signal by detecting variation of timings of first and second variable delay mode register commands, which is generated based on the mode register command, during the mode register read operation. The data output control circuit delays an operation code, which is generated based on the mode register command, by a second predetermined delay period to generate a delayed operation code. The data output control circuit outputs the delayed operation code as data in synchronization with the mode register strobe signal.