An adaptive switch circuit is provided, which includes a CMOS switch, an off-level voltage generator, and a booster circuit. The CMOS switch includes first PMOS and NMOS coupled transistors. The generator provides, via first and second outputs, first and second voltage levels, and includes second PMOS and NMOS transistors. The second PMOS transistor is series connected between VDD and a first bias source and the second NMOS transistor is series connected between VSS and a second bias source. The booster circuit, which is coupled to the generator between its outputs, and to the PMOS and NMOS gates of the CMOS switch, capacitively stores during off level first and second boost voltages, which are coupled to the PMOS and NMOS gates. The boost voltages are offset from VDD and VSS, respectively, each by approximately a threshold voltage of the respective transistor type.