TMUX1308: Low voltage Ax and ~E

The switches can pass any voltage between GND and VDD.

So when S = 5 V, D is also 5 V. (Well, the 10 µA current creates a voltage drop of 2.7 mV.)

Daniel,

Your ~E will actually turn the switch off so you'll see D = 0V here. Refer to the truth table for the TMUX1308 and you'll see that the enable pin is active low. Given A0=A1=A2=3.3V and ~EN = 0V you'll only turn on the path for S7. 

With regard to the signal you can pass through, this is in the datasheet. You'll see that the IO voltage max limit is Vdd, so with Vdd = 5V you can definitely get close to 5V (there will be a slight voltage drop, but nothing concerning, in the low mV range). 

Hope this helps!
Rami