To minimise the conduction losses and improve efficiency in medium speed circuits, Vishay has recently announced the launch of polyimide passivated diodes in order to attain increased reliability under high operating temperature up to +175 °C. Polyimide is a polymer of imide monomers. Due to high heat-resistance; polyimides enjoy diverse applications in high temperature environment. Diodes when passivated with polyimide exhibit a reliable insulation when subjected to various types of environmental stresses making is suitable for applications such as drives, UPS, Solar and Welding Inverters.
According to the media release, “The Ultra-soft recovery FRED Pt Gen 4 Ultrafast Diodes are designed for use as anti-parallel diodes in combination with Vishay’s new Trench insulated gate bipolar transistors (IGBTs). Together, the Ultrafast diodes and IGBTs provide low EMI and plug-and-play reliability for single- and three-phase inverters, as well as full- and half-bridge DC/DC converters.”
Referring to the product release, the ultra fast diodes are offered as die in wafer form. Adding further, the release mentions, “Vishay offers 28 new 600V and 650V in H and U series that propose to deliver ultra-low forward voltage and reverse recovery charge to trim down the losses and boost efficiency, while their extremely soft turn-off behaviour minimising over-voltages under all switching conditions. The Gen 4 diodes feature improved technologies in their active area and termination design that allows forward currents ranging from 12A to 250A in smaller die sizes than previous-generation devices while their reduced thickness improves thermal impedance. Also, 600 V “U” series diodes feature extremely low forward voltage down to 1.4V for 600V devices and 1.48V for 650V devices. Optimised to deliver high speeds for higher-frequency applications, H series diodes offer reverse recovery times down to 25ns with low typical forward voltages down to 1.65V for 600V devices and 1.74V for 650V devices.”