I designed and manufactured a PCB which utilized the LTC3895 to produce 5V DC power from 110V DC power. I referred to the standard schematic in the datasheet. Nothing changed, but the real output voltage followed the VIN. I am confused and do not know how to solve the problem.
I still list some data here.
1) the INTVCC is 5V.
2) the OVLO is 0.1V, far less than threshold 1.1V
3) input 12V DC, higher than minimum input voltage 8.0V
4) all testing is without load, because I am afraid of that high output voltage destroy the circuit.
It is not very clear what the problem is. Please put more details and probably schematic and waveforms. You may be correct that if there was damage, it may certainly be caused by high voltage if you tested the board at 110V.
We have a demo board that can support up to 130V. It is best to start with that board to study and modify from there. Use LTspice to check design.