1. Reverse leakage current (Ir @ Vr): STPS2045CT is rated at 100 µA, approximately 1.72 times that of the TST20H45C (58 µA). Under high‑temperature or high‑reverse‑voltage conditions, the STPS2045CT will exhibit higher static power loss and thermal dissipation, which may impact system efficiency and temperature rise. This factor should be accounted for in designs employing multiple parallel devices or in applications with stringent power‑consumption constraints. 2. Maximum junction temperature (Tj Max): The STPS2045CT is rated for 175 °C, notably higher than the 150 °C rating of the TST20H45C. This indicates that the STPS2045CT’s die technology or packaging materials offer a greater thermal reliability margin. Under identical cooling conditions, it can tolerate higher ambient operating temperatures or withstand more severe transient thermal stress, providing a reliability advantage in compact or poorly‑ventilated designs. Substitution Recommendation: For applications with elevated ambient temperatures (e.g., >85 °C) or challenging thermal environments, the STPS2045CT is preferred. If the system imposes strict limits on static power loss or operates consistently near the maximum reverse voltage, the TST20H45C is the better choice. For general industrial or consumer electronics applications, the two devices can be interchanged directly.