What the zero-recovery spec means for switching losses
The IDH04G65C5XKSA2 is a 650 V, 4 A Silicon Carbide Schottky diode from Infineon's CoolSiC™+ generation. Its defining characteristic is zero reverse recovery time — listed as No Recovery Time > 500 mA — which eliminates the charge-storage tail that forces hard-switched silicon diodes into a lossy, noisy commutation. For a power supply or motor drive engineer, that means the diode contributes no switching loss at turn-off; the full thermal budget goes to conduction loss (1.7 V forward drop at 4 A) and the I²R of the PCB trace.
Thermal headroom and package reality
Junction temperature is rated to 175 °C, which is 25 °C higher than most silicon ultrafast diodes. That extra margin lets you push the 4 A average current through a smaller heatsink — or run the same heatsink at a higher ambient — but only if the TO-220-2 tab is properly sinked. The PG-TO220-2-1 package has a single large cathode tab; the thermal resistance to case depends on the mounting torque and thermal interface material. The 130 pF capacitance at 1 V reverse is low enough that the diode does not add significant ringing on a well-laid-out 100 kHz PFC stage.
The CoolSiC™+ series is Infineon's current-generation SiC Schottky family; the IDH04G65C5XKSA2 is the 4 A, 650 V through-hole variant in tube shipment.