A multiplexer includes a charging circuit; a plurality of sampling switches receiving a plurality of input signals; and a plurality of boosting circuits connected between the sampling switches and the charging circuit and sharing the charging circuit. First and second charging switches of the charging circuit are controlled by a first clock signal. Each of the boosting circuits includes a first boosting switch connected to a first node of the charging circuit and a gate of one of the sampling switches, a second boosting switch connected between a second node of the charging circuit and the one sampling switch, and a level shifter configured to control the first boosting switch and the second boosting switch in response to a second clock signal and a selection signal.