1. Current Capability & Die Technology: The MBRF2545CT is rated for an average rectified current of 12.5 A per diode (usable in parallel configuration), whereas the SBRF2045CT lacks a specified rating—though the “20” in its part number typically suggests a capability around 20 A. This indicates that the MBRF2545CT likely employs a more advanced silicon process within the same package, achieving higher current density and reliability, which explains its higher cost. For the original design, substitution would provide greater current margin. 2. Forward Voltage Drop (Vf) & Conduction Loss: The SBRF2045CT exhibits a lower Vf (750 mV @ 10 A) compared to the MBRF2545CT (820 mV @ 30 A). This does not imply superior performance of the former; rather, the test conditions are entirely different. The MBRF shows only a modest increase in Vf even at 30 A, indicating lower on‑state resistance. Consequently, under actual high‑load conditions, the MBRF may deliver lower conduction loss, reduced temperature rise, and higher efficiency. 3. Reverse Leakage Current & Power Dissipation/Reliability: At a reverse voltage of 45 V, the SBRF2045CT leakage is 1 mA, while the MBRF2545CT is only 200 µA—a factor of 50 lower. The reduced leakage directly lowers static power dissipation, which positively impacts system efficiency and thermal management, especially in high‑temperature or high‑voltage applications. This also reflects differences in die material and process quality. 4. Operating Junction Temperature Range: The MBRF2545CT offers a junction temperature range of –65 °C to 150 °C, superior to the SBRF2045CT’s –55 °C to 150 °C. This provides a greater reliability margin in extreme environments, such as automotive cold‑cranking or industrial low‑temperature startups.