What are the impact of fast recovery diodes on reliability in applications?

What is the principle of fast recovery diode surge failure, and what is the difference betweenfast recovery diode avalanche failure and edge failure?

In fast recovery diode applications, VF and Qrr are the main factors that affect the temperature rise. VF is mainly affected by IF and temperature, and can be suitable for high-power applications.

The main factors that affect reliability in diode applications are IFSM and EAS. IFSM is the maximum non-repetitive sinusoidal half-wave inrush current allowed by the diode, and EAS is the single avalanche energy that the diode can withstand. In practical applications, if there is a large capacitance in the circuit at the moment of power-up, a large inrush current will be generated, which requires a fast recovery diode to have a large surge tolerance (or a parallel bypass diode). Normally, the forward inrush current of 10ms sine wave is given in the datasheet, which can be converted to I2T to evaluate whether it meets the actual application requirements. IFSM is a negative temperature coefficient, and as the temperature rises, the diode's ability to withstand surge currents decreases. A surge failure is a high-current failure in which the entire active zone tends to melt. In inductive loads, the higher failure rate is often the worse EAS. The EAS capability is related to the withstand voltage of the diode and increases slightly as the temperature increases. Due to the large electric field strength at the edge, there are many edge failures in avalanche failure.

fast recovery diode are very popular power devices, and you can refer to the parameters and characteristics of fast recovery diodes when selecting.