1. Current Rating and Thermal Design The STPS3L60UY has a rated current of 3A, while the SS26T3G is rated for 2A. Under identical operating conditions, the SS26T3G will exhibit higher junction temperature rise, necessitating a reassessment of the thermal design. Direct substitution is not permissible if the original circuit operates near 3A. 2. Lack of Automotive-Grade Qualification The STPS3L60UY is AEC-Q101 qualified and marked as "Automotive Grade." The SS26T3G does not list equivalent certification. For automotive or high-reliability industrial applications, the SS26T3G may not meet supply chain or reliability requirements. 3. Reverse Leakage Current and High-Temperature Performance The SS26T3G has a higher reverse leakage current (200 µA @60V) compared to the STPS3L60UY (150 µA @60V), and no high-temperature leakage current curve is provided. In high-temperature or low-power-sensitive applications, this may impact system efficiency or thermal stability. 4. Differences in Forward Voltage Test Conditions The Vf of the STPS3L60UY is specified at 3A, whereas the SS26T3G is tested at 2A. When operating within the 2-3A range, the SS26T3G may incur higher conduction losses. Efficiency degradation must be evaluated based on the actual operating current. --- Recommendation: Substitution is acceptable for general industrial or consumer electronics applications where the operating current is ≤1.6A (maintaining a derating margin >20%). For automotive, high-temperature, or high-reliability scenarios, it is advisable to prioritize the original part or seek an alternative with equivalent qualifications.