What are the reliability impacts of fast recovery diodes in applications?

What is the principle of fast recovery diode surge failure? What is the difference between avalanche failure and edge failure of fast recovery diodes?

The main factors affecting temperature rise in fast recovery diode applications are VF and Qrr. VF is mainly affected by IF and temperature, and can be suitable for high-power applications. The main factors affecting reliability in diode applications are IFSM and EAS. IFSM is the maximum non repetitive sine half wave surge current allowed by a diode; EAS is the single avalanche energy that a diode can withstand. In practical applications, at the moment of power on, if there is a large capacitor in the circuit, a large surge current will be generated, which requires fast recovery diodes with high surge tolerance (or parallel bypass diodes). Normally, a 10ms sine wave forward surge current is given in the data table, which can be converted into I2T to evaluate whether it meets practical application requirements. IFSM is a negative temperature coefficient, and as the temperature increases, the diode's ability to withstand surge currents decreases. Surge failure is a high current failure, and the entire active area often melts. In inductive loads, poor EAS often leads to higher failure rates. The EAS capability is related to the withstand voltage of the diode and slightly increases with increasing temperature. Due to the high electric field strength at the edge, there are more occurrences of edge failure in avalanche failure.

Fast recovery diodes are popular power devices, and when choosing, you can refer to the parameters, characteristics, etc. of fast recovery diodes.