A typical CMOS switch would have an internal ESD diode to the supply pin rated for ≅30 mA that would be turned on and a series limited resistor would be needed. However, any conducted current would be injected into the supply rail potentially damaging the system, unexpectedly turning on other devices on the same supply rail, or requiring additional components for protection. The TMUX13xx implementation also handles this scenario with a series limiting resistor; the current path, however, is now to GND which does not have the same issues as the current injected into the supply rail.