The TMUX1308 and TMUX1309 can operate without any external components except for the supply decoupling capacitors. If the parts desired power-up state is disabled, then the enable pin should have a weak pull-up resistor and be controlled by the MCU through the GPIO. All inputs being muxed to the ADC of the MCU must fall within the recommended operating conditions of the TMUX1308 and TMUX1309, including signal range and continuous current. For this design with a supply of 5 V, the signal range can be 0 V to 5 V; the maximum continuous current can be 100 mA at an ambient temperature of 85°C or 25 mA at 125°C.