1. Reverse Voltage (Vr): STTH102 is rated for 200V, while EGP10B is rated for 100V. In circuits where bus voltage, inductive turn-off spikes, or any reverse voltage may exceed 100V, the EGP10B faces a severe risk of breakdown. This is the primary factor precluding substitution. 2. Reverse Recovery Time (trr): STTH102 has a trr of 20ns, compared to 50ns for the EGP10B. In high-frequency circuits such as switching power supplies and PFC stages, the longer reverse recovery time leads to increased switching losses (both in the diode itself and the corresponding switching transistor) and more severe electromagnetic interference (EMI). If the original design was based on 20ns performance, direct replacement could result in reduced efficiency or overheating. 3. Reverse Leakage Current (Ir): At their respective maximum rated voltages, the leakage current of the EGP10B (5µA @100V) is significantly higher than that of the STTH102 (1µA @200V). Under the same high-voltage operating conditions (e.g., near 100V), the actual leakage current of the EGP10B would be even higher, potentially increasing system static power consumption. This may have subtle implications for low-power or high-voltage monitoring circuits. 4. Maximum Junction Temperature (Tj Max): STTH102 is rated for 175°C, while EGP10B is rated for 150°C. The STTH102 offers greater thermal design margin in high-temperature environments or under high-power dissipation conditions. Substitution could introduce reliability risks in designs where thermal management is critical.