I am using ADN4655 in an application to isolate LVDS and I have one input and one output on another IC that are not used. I didn't see any guidelines for the LVDS isolators on what to do with the unused pins. I am assuming the best thing to do for the output is terminate it with 100 ohms, but I'm not sure what the best approach at the input is.
ADN4655 should be terminated at the input, and due to the built-in terminated/idle failsafe, there will then be no chatter on the channel and the output will be a fixed logic 1.
For the output, you could leave it open to save power (driver won't use as much current with no termination).
Thanks! Just to clarify, you mean to terminate it at the input with 100 ohms and not bias it to any particular logic level?
Termination at the input with 100 ohms will be sufficient for ADN4655 and ADN4656. ADN4654 doesn't have the terminated failsafe built-in, so external biasing would be required (pull-up on D+, pull-down on D- to ensure >100 mV for logic 1).
ADN4655 will output a stable logic 1 when the input is just terminated by 100 Ohm, no other connections/biasing required.