1. Voltage Rating and Design Margin: The FDP has a Vdss of 60V, which is lower than the EKI's 75V. This directly reduces the system's margin for voltage spikes. In environments with inductive loads, switching transients, or power supply fluctuations, there is an increased risk of overvoltage breakdown. If the original design operates near 75V or in a high-noise environment, reliability will be compromised after substitution. 2. Thermal Performance and Current Rating: Both parts have similar rated currents at case temperature (Tc) (80A vs. 85A). However, the FDP's rated current at ambient temperature (Ta) is only 15A, significantly lower than the EKI (which does not specify a Ta value, typically implying a higher capability). This indicates the FDP is more dependent on an effective heatsink to achieve its high-current performance. Under identical cooling conditions, the FDP's actual sustainable continuous current may be substantially lower than the EKI's, creating a high risk of overheating. 3. Dynamic Performance and Drive Requirements: The FDP features significantly lower gate charge (Qg) and input capacitance (Ciss) (66nC vs. 91nC; 3000pF vs. 6340pF), resulting in faster switching speeds, lower switching losses, and a more driver-friendly profile. However, its gate threshold voltage (Vgs(th)) is higher (4V vs. 2.5V). This necessitates ensuring a sufficient drive voltage (>10V) for full turn-on to avoid increased on-state resistance and consequent heating due to insufficient gate drive. 4. On-State Resistance (Rds(on)) Test Conditions: The FDP's 7.0mΩ is specified at 80A/10V, whereas the EKI's 6.6mΩ is at 44A/10V. The differing test currents make a direct numerical comparison misleading. The FDP's specification at a higher current suggests its datasheet value may emphasize high-current performance. However, its actual conduction loss at medium currents (e.g., 44A) should be determined from its output characteristic curves and may be comparable or superior to the EKI. 5. Technology Platform: The FDP utilizes onsemi's PowerTrench® technology, typically optimized for low Qg and low switching loss. The EKI does not specify a special technology. This explains the differences in dynamic parameters. After substitution, system switching frequency and efficiency characteristics may change.