1. Current Handling & Thermal Performance Trade-off The FCP104N60 offers significantly higher continuous drain current (37A) and maximum power dissipation (357W) compared to the STP34N65M5 (28A, 190W). This indicates a larger die size and/or lower thermal resistance, making the FCP part more suitable for high-power applications. The STP34N65M5 must be used with strict derating. 2. Divergent Switching Performance Optimization The STP34N65M5 features 24% lower total gate charge (62.5nC vs. 82nC) and lower input capacitance than the FCP104N60, resulting in lower switching losses and simpler gate drive design. This makes it better suited for high-frequency operation. Note that the STP part has a higher maximum Vgs(th) (5V), requiring sufficient gate drive voltage margin. 3. Rds(on) Test Conditions Imply Linear Region Differences The STP34N65M5's Rds(on) (110mΩ) is specified at 14A, while the FCP104N60's (104mΩ) is tested at 18.5A. Under high actual load currents, the STP part may exhibit higher conduction losses, as its specified resistance is both slightly higher and measured at a lower current. 4. Voltage Rating & Process Technology The STP34N65M5 utilizes MDmesh™ V technology, offering a slightly higher 650V breakdown voltage and characteristics favorable for soft-switching topologies. The FCP104N60 employs SuperFET® II technology, which is more optimized for hard-switching performance and thermal robustness.