SCDS388A November 2018 – November 2018 TMUX1108
The TMUX1108 can be operated without any external components except for the supply decoupling capacitors. If the device desired power-up state is disabled, the enable pin should have a weak pull-down resistor and be controlled by the MCU via GPIO. All inputs being muxed to the ADC must fall within the recommend operating conditions of the TMUX1108 including signal range and continuous current. For this design with a supply of 3.3 V the signal range can be 0 V to 3.3 V and the max continuous current can be 30 mA.
The design example highlights a multiplexed, data-acquisition system for highest system linearity and fast settling. The overall system block diagram is illustrated in Figure 32. The circuit is a multichannel, data-acquisition signal chain consisting of an input low-pass filter, mux, mux output buffer, SAR ADC driver, and the reference buffer. The architecture allows fast sampling of multiple channels using a single ADC, providing a low-cost solution.