1. Switching Performance & Losses: The gate charge (Qg) of the IPP60R360P7XKSA1 is only 13nC, significantly lower than the 32nC of the STP15N80K5. At the same switching frequency, the former requires substantially lower drive losses and drive current, offers faster switching speed, and contributes to higher overall system efficiency. This makes it particularly suitable for high-frequency switching applications (e.g., PFC, LLC resonant converters). The high Qg of the latter can lead to a sharp increase in switching losses, and the original drive circuit may be inadequate. 2. Technology Platform & Optimization Targets: The IPP60R360P7XKSA1 is based on Infineon's CoolMOS P7 technology, which is optimized for an excellent figure-of-merit balancing extremely low switching and conduction losses. The STP15N80K5 utilizes ST's SuperMESH5 technology, focusing more on achieving low on-state resistance at high breakdown voltages. Their technological paths differ: the former is optimized for high-efficiency, high-frequency switching, while the latter emphasizes on-state performance under high voltage stress. 3. Misconception Regarding Thermal Resistance & Power Dissipation: The STP15N80K5's specified 190W power dissipation is a theoretical value calculated under ideal conditions (infinite heatsink, case temperature of 25°C), intended only for comparison within its own product family. The practical heat dissipation capability of a TO-220 package is limited by its package thermal resistance, where the junction-to-ambient thermal resistance (RthJA) is the critical parameter. This value is typically in the same order of magnitude for both devices. The apparent discrepancy between the 41W and 190W ratings stems primarily from different test/labeling conditions and does not indicate a several-fold difference in real-world heat dissipation capability. However, the IPP60R360P7XKSA1's rating is more representative of typical application conditions. 4. Substantial Difference in Voltage Rating: The 800V vs. 650V rating reflects not just a higher nominal value but also differences in the internal semiconductor structure and electric field design. Using an 800V-rated device in a 650V application typically sacrifices some switching speed (due to higher capacitances) and cost-effectiveness. The original design's use of a 650V device indicates sufficient voltage margin; switching to an 800V part offers no performance benefit and may introduce negative effects due to higher Qg and output capacitance (Coss). Conclusion: These are devices optimized for different application priorities. If the original circuit was designed around the low-switching-loss characteristics of the IPP60R360P7XKSA1, replacing it with the significantly slower-switching STP15N80K5 will likely degrade efficiency and cause drive-related issues, making it an unviable substitute. Any substitution assessment must focus on dynamic parameters like Qg, Ciss, and Coss, rather than solely comparing voltage and current ratings.