I'm designing a high voltage asynchronous buck converter where the datasheet of the controller suggests that output diode should have ultra fast recovery time no more than 50 ns. The reverse voltage should be >= 1300 and the current 1A. Looking in digikey I found this one D1408-FF11500 which says that the 1.5 kV one has 50 ns recovery time, but the voltage drop is 6V. Isn't this too much? Should I look for a Schottky diode instead? This one STTH512 has typical recovery time of 48 ns, but it's 1.2kV. Could be okay, but I have less margin in the reverse voltage. The input voltage of the converter is 1kV max.