Hi ADI expert
I use LTC4266 to design a 4 port POE IPC
May I have your help to check my schematic as attachment
I didn't generate -54V from a isolated power supply but simply generated it from my 12V power source with LTC's boost LTC3769
We currently don't have an LDO capable of handling the requirements of your application.
For the Step- up converter, You could check out LT8364 for non-synchronous and LTC3769 for a synchronous converter. I would also suggest using LTpowerCAD VII…
If your application would use LT8210 purely as a boost converter, I would suggest looking on reference design linked below. The design is for a high power Boost converter which uses LTC3769 and LT8551.