My question was for the TS.

ak

 

If you are unsure about the output impedance, just check the datasheet of whatever chip flavor you want to use. As I recall it should be a few megaohms at least, or if they don´t state impedance there should be leakage current in off state.

 

her* mind you . It actually works when I add up the 10k resistors which leads me to another problem: I need this circuit to feed some other circuit with a variable input impedance that is to be measured. so my Demux's behaviour will depend on the second circuit and that is not good at all.
I'm going to need a voltage follower I suppose?

The selected output is connected to the input with an impedance of approx. 125 Ohms. Other outputs are connected to the input with very, very high impedance. +/-10pA leakage at 10V, and that works out to 1000 GOhm, to give you an idea of the order of the impedance. If the input impedance of the circuit that you would connect to this output is, say 1 MOhm, then the drop during on, will be 10uA X 125 Ohms = 1.25mV, and when off will be almost 10V, giving an output of 10 pA X 1 MOhm = 10uV, almost zero. You could calculate for your circuit values. You need to take the decision as to whether this is acceptable.