The select (SEL) pin of the TMUX1248 controls which switch is connected to the drain of the device. When a given input is not selected, that source pin is in high impedance mode (HI-Z). The control pins can be as high as 5.5 V.

The TMUX1248 can be operated without any external components except for the supply decoupling capacitors. Unused logic control pins should be tied to GND or V_DD in order to ensure the device does not consume additional current as highlighted in Implications of Slow or Floating CMOS Inputs. Unused signal path inputs (Sx or D) should be connected to GND.