1. Rated Current & Forward Voltage (Vf): The MBRB20100CTG has twice the rated current (10A) of the STPS10H100CG-TR (5A), implying a larger die area. Their respective maximum Vf specifications are 850mV@10A and 730mV@5A. At an identical 5A operating point, the MBRB20100CTG's actual Vf will typically be significantly lower than 730mV, resulting in lower conduction loss. However, under light-load conditions (below 2-3A), its efficiency may be inferior to the original part due to its larger junction capacitance and differing Vf-I characteristics. 2. Reverse Leakage Current (Ir): At 100V reverse bias, the leakage current of the MBRB20100CTG (100µA) is an order of magnitude higher than that of the STPS10H100CG-TR (3.5µA). This stems primarily from the fundamental physical principle that a larger silicon area provides more paths for leakage. This difference becomes critical in high-temperature, high-voltage operating environments, where the MBRB20100CTG will generate higher static power dissipation, potentially impacting system temperature rise and efficiency. This is particularly important for thermally sensitive designs or battery-powered applications. 3. Product Series & Optimization Focus: The MBRB20100CTG belongs to onsemi's "SWITCHMODE™" series, which typically indicates optimization for switching characteristics in power supplies (e.g., PFC, DC-DC). It may feature softer reverse recovery or superior Qrr performance, aiding in reduced switching noise and lower EMI. The ST part, lacking a designated special series, is likely a more general-purpose standard product. This difference could be beneficial if the original application is sensitive to switching noise. Summary: The MBRB20100CTG can be considered an upgrade replacement if the design has sufficient margin and can accommodate higher cost and static loss. However, if the original design has precise requirements for efficiency, thermal performance, or cost, re-validation based on actual operating conditions (current, voltage, temperature) is mandatory.