SNVSBZ3 June 2021 LM5168-Q1
The secondary output diode must block the maximum input voltage reflected to the secondary by the transformer turns ratio. Equation 26 is used to determine the maximum reverse voltage on the diode. For this example, a value of 70 V is calculated and a 100-V diode is chosen. The diode current rating should be at least equal to the secondary output current with an appropriate factor of safety. Schottky diodes are the best choice for this application. Ultra-fast recovery diodes can also be used. In any case, choose a diode with the lowest turn-off time.