Active production — what it means for a BOM line
The 1N6628U: For a procurement desk, Active means the manufacturer continues to accept orders and the part is supported in the current BOM revision.
660 V, 1.75 A — the switching rectifier's duty envelope
Rated for 660 V DC reverse voltage and 1.75 A average rectified current, this fast recovery diode handles the primary-side bulk rectification in off-line power supplies and DC-link snubbers where the reverse voltage stress sits above the 400 V bus. The 45 ns reverse recovery time (trr) classifies it as a fast recovery device per the JEDEC definition (trr ≤ 500 ns at Io > 200 mA) — the switching loss at 100 kHz is manageable in a continuous-conduction-mode boost or flyback topology.
SQ-MELF B — surface-mount hermetic footprint
The SQ-MELF B (Surface Mount MELF, B case) is a hermetic glass-passivated package suited for high-reliability and military/aerospace applications where moisture resistance and thermal cycling endurance are required.
Junction temperature and leakage at the high-voltage rail
Reverse leakage at 660 V is only 2 µA at 25°C — it doubles with temperature, so at 125°C junction the leakage contribution to the thermal budget should be checked against the derating curve. Capacitance is 40 pF at 10 V reverse bias and 1 MHz — this is low enough that the diode does not load the switching node significantly in a 100–500 kHz converter, but it contributes to the snubber design in high-voltage ringing circuits.