TS5A9411: connection condition when the VCC is not powered

In theory, the gate-to-source threshold voltage of the internal MOSFETs cannot be reached when the device is powered off, so there should be no direct connection.

However, the analog I/Os are diode-clamped to the power rails. So you are not allowed to apply a non-zero voltage to any I/O.

Hey Zach,

This is indeterminate and this would also be violating the device datasheet ROC as this doesn't have powered off protection. 
Clemens could be correct here, however I believe you may actually see it staying in the on state since this is a transmission gate architecture, depending on the more detailed internal architecture, the gate on the pfets may not be able to pull up high enough to actually turn the FET off. So I would suspect that the Vs would be higher than Vg so you would keep the device ON. But as I mentioned, this violations the specs so we don't have this tested and wouldn't know the actual results. 

We do have some other 1ch 2:1's that do have power off protection though : Analog switches & muxes product selection | TI.com. Can we use this?

Thanks,
Rami