1. Rated Current & Forward Voltage (Io & Vf): 18 A/600 mV vs. 15 A/560 mV. At the same operating current of 15 A, the theoretical conduction loss of the substitute (VS‑18TQ035STRR‑M3) will be slightly higher than that of the original part. Its higher current rating primarily offers greater overload capability and safety margin, not improved conduction performance. 2. Reverse Leakage Current (Ir): 2.5 mA vs. 1 mA @ 35 V. The substitute’s leakage current at room temperature is 2.5 times that of the original. At elevated temperatures (approaching the maximum junction temperature of 175 °C), this difference increases exponentially, potentially leading to higher static power dissipation and thermal management challenges. 3. Junction Capacitance (Cj): 1400 pF vs. 900 pF @ 5 V, 1 MHz. The substitute’s junction capacitance is about 55 % higher. In high‑frequency switching applications (e.g., high‑frequency DC‑DC converters), this directly results in increased switching losses and potentially more severe voltage spikes, affecting efficiency and EMI performance. 4. Manufacturer & Price: Vishay vs. SMC, with a price difference of approximately 94 %. This reflects brand premium, possible performance consistency variations, and manufacturing or supply‑chain factors, but does not affect the electrical feasibility of substitution.