On page 30 of the LT3757 boost/flyback/sepic/inverting controller; there's an application for a 300V flyback design.
The switching MOSFET selected for this design is a VISHAY SILICONIX Si7850DP which has a max drain-source voltage of 60V.
When simulating the circuit with LTSpice I see voltages in excess of hundreds of volts at the drain.
Am I missing something here? It seems like this MOSFET selection is not adequate for the application.
[edited by: tpttr at 2:43 AM (GMT -4) on 14 Sep 2018]