As for ADUM2852E,
I will supply +5V on VISOIN, not 3.3V internal DCDC power.
Of cource, VISOOUT will be still open. And not connect this to another load.
Is this no problem or not?
If no problem, how should I think the ratings on datasheet?
The ratings have been made the reason that connect VISOOUT with VISOIN, I think.