1. Different Rds(on) Test Conditions: The FDP5800’s Rds(on) (6 mΩ) is specified at 80 A, whereas the PSMN7R6-60PS (7.8 mΩ) is rated at 25 A. The former provides clearer conduction loss characteristics at high current, while the latter requires reviewing the full datasheet curves to assess losses under actual operating currents. 2. Significant Gate Characteristic Differences: The PSMN7R6-60PS features a gate charge (Qg) of only 38.7 nC, substantially lower than the FDP5800’s 145 nC, and its input capacitance (Ciss) is about 70% smaller. This indicates much faster switching, lower switching losses, and reduced drive requirements—making it particularly suitable for high-frequency switching applications such as SMPS. Note, however, that the PSMN7R6-60PS requires 10 V to fully turn on, while the FDP5800 turns on at 4.5 V. Drive voltage compatibility must be confirmed during substitution. 3. Divergent Thermal Design Implications: The FDP5800 is rated for 242 W (Tc), higher than the 149 W (Tc) of the PSMN7R6-60PS. Additionally, the FDP5800’s Id rating of 14 A (Ta) emphasizes its natural convection capability. This suggests the FDP5800 may have lower package thermal resistance or be more robust in the absence of forced cooling. In contrast, the PSMN7R6-60PS relies on its low Qg for efficiency gains but offers less thermal margin, requiring assurance that the thermal management system meets the application demands. 4. Technology Generation Gap: The FDP5800 utilizes PowerTrench® technology, focusing on optimized on-resistance and cost. The extremely low Qg and Ciss of the PSMN7R6-60PS indicate it employs a newer generation of super-junction or similar technology, targeting switching performance. In circuits where dynamic losses dominate, the latter may deliver higher overall efficiency. In summary, substitution feasibility heavily depends on application frequency, drive voltage, and thermal conditions. Prototype testing under target operating conditions is strongly recommended.