Fast Recovery Epitaxial Diodes (FRED) are ultrafast diodes whose switching behavior leads to different dependencies between the forward voltage, reverse voltage and reverse time.
FRED diodes are combined with field-effect transistors( FET) to form FredFETs. These are power spring-effect transistors that are specifically used for switching inductive loads such as those found in motors and transformers.
Important parameters for the turn-on and turn-off behavior of FredFETs are given by the dependence between the forward voltage drop and the blocking time and can be influenced by manufacturing techniques. Any specific FredFET technology must be realized via the trade-off between forward voltage and recovery times.