600 V fast recovery in a hermetic-grade surface-mount package
The 1N6663US is a standard fast recovery diode rated for 600 V DC reverse voltage and 500 mA average rectified current, with a maximum forward voltage of 1 V at 400 mA. Its recovery time is specified as ≤ 500 ns at forward currents above 200 mA, making it suitable for snubber, freewheeling, and clamp circuits where switching losses matter. The SQ-MELF (D-5A) package is a surface-mount ceramic body with metallized ends, offering a hermetic-like seal and excellent thermal cycling performance compared to plastic SMD packages.
Leakage and temperature margin for the test bench
Reverse leakage is specified at 50 nA maximum at 600 V — a tight figure that holds across the full -65°C to +175°C junction temperature range. For a calibration or verification engineer, this means the diode's blocking behavior is predictable well beyond the typical 125°C limit of commercial rectifiers, and the leakage won't drift enough to upset a high-impedance bias network over temperature. The 1 V forward drop at 400 mA is a typical figure; the actual drop at 500 mA will be slightly higher but still within the 1.1–1.2 V range for a 600 V fast recovery device. If you are characterizing this part on a curve tracer, sweep it to the full 500 mA rated current and note the Vf at your operating point — the datasheet's typical curve is the reference, not the limit.
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