Semiconductor memory input/output device

The present invention relates to a semiconductor memory with respect to input and output devices that support multi-mode of operation. The disclosed invention is used for input and output of signals to the plurality of operation modes, the first and second selected corresponding to the selected operation mode having a plurality of pad use; The first and the second setting portion and the signal generation control signal and outputting the mask control signal by the operation mode signal with information about the expansion mode set signal with the resist having the operation mode information for the purpose; First outputting a read data strobe signal to a selected pad, the lower the output buffer section of the first receiving the lower data mask signal from the selected pad lower input buffer comprises parts of the first set by the signal lower output buffer portion and the lower input lower input unit for selecting any one of an operation of the buffer unit; The second starting at the upper output buffer portion and the second selection pads for outputting the read data strobe signal is inverted to the selected pad an upper input buffer for receiving the upper data mask signal and the second upper output by the setting signal and a mask control signal an upper input unit for selecting any one of an operation of the buffer portion and the upper input buffer unit; by including the effect of improving the area by reducing the number of pads.