1. Voltage Rating & SOA: The STW11NM80 features a significantly higher Vdss (800V) compared to the TK14N65W5 (650V). In applications operating below 650V, the STW11NM80 offers greater voltage margin and enhanced reliability, particularly in circuits prone to voltage spikes (e.g., inductive loads). However, the higher voltage rating typically correlates with a higher output capacitance (Coss), which can impact switching losses. 2. Current Capability & On-Resistance: The TK14N65W5 is rated for a continuous drain current (Id) of 13.7A (Ta), while the STW11NM80 is rated for 11A (Tc). The key distinction lies in the different test conditions (Ta - ambient temperature vs. Tc - case temperature), making a direct comparison misleading. The more critical parameter is Rds(on). At similar current levels and Vgs, the TK14N65W5's 300mΩ is notably lower than the STW11NM80's 400mΩ. For the same conduction current, the TK14N65W5 will exhibit lower conduction loss and higher efficiency. 3. Power Loss & Thermal Performance: The STW11NM80 has a higher nominal maximum power dissipation (150W, Tc) than the TK14N65W5 (130W, Tc), indicating its package can inherently handle greater thermal load. However, the actual junction temperature depends on conduction losses (from Rds(on)), switching losses, and the system's thermal design. The STW11NM80's higher power rating may be partially offset by its higher Rds(on). 4. Switching Performance: The TK14N65W5 has slightly lower total gate charge (Qg) and input capacitance (Ciss) than the STW11NM80 (40 nC vs. 43.6 nC; 1300 pF vs. 1630 pF). With the same gate drive circuit, the TK14N65W5 may switch slightly faster, with marginally lower switching losses and slightly reduced drive current requirements. This is a factor to consider in high-frequency switching applications (e.g., SMPS).