AN4337 Datasheet, PDF (1/14 Pages) STMicroelectronics – power MOSFETs are considered rugged with respect to the avalanche

AN4337
Application note
The avalanche issue: comparing the impacts
of the I_AR and E_AS parameters
By Vittorio Giuffrida
Introduction
Generally, power MOSFETs are considered rugged with respect to the avalanche
phenomenon, however, the quantification of the level of ruggedness depends on the I_AR
avalanche current and E_AS avalanche energy. These two parameters determine the capacity
of a MOSFET to be safe during the avalanche. This paper explores the theory of the
avalanche effect in a flyback converter, in order to understand how the I_AR and E_AS
parameters affect MOSFET operation and, consequently, how to manage a voltage
overshoot higher than the V_(BR)DSS absolute maximum rating.
June 2014
DocID025012 Rev 1
1/14
www.st.com