The TMUX112x devices can be operated without any external components except for the supply decoupling capacitors. All inputs signals passing through the switch must fall within the recommend operating conditions of the TMUX112x including signal range and continuous current. For this design example, with a supply of 3.3V, the signals can range from 0V to 3.3V when the device is powered. The maximum continuous current can be 30mA.

Photodiodes commonly have a current output that ranges from a few hundred picoamps to tens of microamps based on the amount of light being absorbed. The TMUX112x have a typical On-leakage current of less than 10pA which would lead to an accuracy well within 1% of a full scale 10 µA signal. The low ON and OFF capacitance of the TMUX112x improves system stability by minimizing the total capacitance on the output of the amplifier. Lower capacitance leads to less overshoot and ringing in the system which can cause the amplifier circuit to go unstable if the phase margin is not at least 45°. Refer to Improve Stability Issues with Low C_ON Multiplexers for more information on calculating the phase margin versus percent overshoot.