Hello planning to use an optocoupler to interface a button meters away from the circuit. The optocoupler ILx series already comes with Common Mode Transient Immunity which would work great for my application. Driving the input of the optocoupler is a Constant current IC BCR401 that is set to 10mA from a separate power supply.
We already know that opto has built in immunity to transient, is my decision of omitting the TVS diode on the twisted pair (place near the optos input cathode) as it would be redundant with the built in one correct?
The BCR401 datasheet has no mention of any form of immunity against transients. Would it be protected by the opto's protection circuitry too? If it need its own protection it would most probably some sort of a TVS diode but i could not figure out where its anode and cathode would be connected because the induction would come from the twisted pair so it has to go to VDD making it not needed ??