When the SEL pin of the TMUX720x is pulled high, the switches will close. When the SEL pin is pulled low, the switches will open. The control pins can be as high as 44 V.

The TMUX720x can operate without any external components except for the supply decoupling capacitors. The SEL pin has an internal Pull-Down resistor of 4 MΩ. If unused, then the SEL pin must be tied to GND so the device does not consume additional current as highlighted in Implications of Slow or Floating CMOS Inputs.