40 A, 400 V standard recovery rectifier
The Vishay VS-40HF40 is a general-purpose standard recovery diode rated for 400 V reverse voltage and 40 A average rectified current. It is built for line-frequency rectification in power supplies, battery chargers, welding equipment, and DC motor drives where switching speed is not the priority.
Forward drop and thermal headroom
Maximum forward voltage is 1.3 V at 125 A — a high-current test point that shows the diode can handle surge conditions well above the 40 A average rating. Junction temperature range spans -65°C to 190°C, giving substantial thermal margin in forced-air or liquid-cooled heatsink assemblies.
Stud-mount package and installation
Housed in a DO-203AB stud-mount package, the VS-40HF40 is designed for chassis mounting with a threaded stud and hex base. The anode connects through the stud to the heatsink, so the mounting surface must be electrically isolated or the heatsink must float. The package suits bus-bar and cable-lug terminations common in high-current industrial rectifier stacks.
Leakage and reverse recovery
Reverse leakage is 9 mA at the full 400 V blocking voltage — a figure that rises with junction temperature, so thermal design should budget for increased leakage at the 190°C limit. Standard recovery time exceeds 500 ns, confirming this is not a fast-recovery or soft-recovery diode; it is intended for mains rectification, not inverter or SMPS output stages.