1. Current Rating and Forward Voltage: The GPP20J is rated for 2A (Vf=1.1V), while the 1N6628 is rated for 1.75A (Vf=1.35V). At the same current level, the 1N6628 exhibits significantly higher conduction loss and heat generation. In practice, the operating current must be strictly limited to ≤1.75A with adequate derating margin; otherwise, thermal overstress and failure may occur. 2. Reverse Recovery Characteristics: The GPP20J is a standard recovery diode (>500ns), whereas the 1N6628 is a fast recovery diode (trr=45ns). In any application involving fast switching—such as switching power supplies, high-frequency rectification, or freewheeling circuits—the 1N6628 substantially reduces switching loss, minimizes voltage overshoot, and lowers electromagnetic interference (EMI), delivering superior performance. This advantage is negligible in 50/60Hz line-frequency rectification. 3. Reverse Leakage Current and Junction Temperature Range: The 1N6628 offers lower reverse leakage current (2μA vs. 5μA @600V) and an extended minimum junction temperature down to –65°C. This indicates better blocking characteristics under high temperature and high voltage, along with suitability for harsher low-temperature environments, providing greater reliability design margin.