ZHCSPX3A October 2022 – November 2022 TMUX7436F
PRODMIX
The normal operation of the application is to take multiple differential inputs and use a 2:1 multiplexer to pass the signal to the downstream instrumentation amplifier. A fault protected switch can add extra robustness to the sytem against fault conditions while also reducing the number of components required to interface with the systems physical input channels.
The Figure 9-1 shows the case where a human wired the condition incorrectly and one of the input connectors shorted to the power board supply voltage. If the board supply voltage is higher than the power supply of the multiplexer, then the TMUX7436F device will disconnect the source input from passing the signal to protect the downstream components. The drain pin of the channels can either be pulled up to the supply voltage (VDD and VSS) through a 40 kΩ resistor or be left floating depending on the state of the DR pin. This can be configured to match the system requirements on how to handle a fault condition.