BTS621 is really nice it feature a lot of stuff like the open drain detection and short-circuit detection (really useful to detect open bulb or died led) and with 100m
of Ron, I could simply couple the digital pins with HCPL2731.
By the way, VO14642AT is a really simple and small device, with built-in insulation and 250m
of Ron
I think I'll use the BTS621 in SMD package, it can drive two loads in one IC and has diagnostic output pin
Another doubt I have is about the ESD protection for the digital inputs, I'm taking in consideration to use TVS diodes to protect the optocouplers, could be useful or completely useless?
Thank you very much for your suggestions