The drain output will be clamped during an overvoltage fault condition. The
ADG5248F, ADG5249F, and ADG5243F have secondary supplies (POSFV, NEGFV) which
will be the clamp voltages on those parts. The switch will turn-off when the
voltage on the input exceeds POSFV/NEGFV by 0.7V and the drain will
pull to the rail (POSFV or NEGFV) that was exceeded.
The ADG5208F and ADG5209F don’t have secondary supply rails, so the drain
output will clamp to the primary supply rails (VDD, VSS) when the input exceeds
VDD/VSS by 0.7V.