1. Voltage Rating & Technology Platform The STP18N55M5 (550V, MDmesh™ V) is optimized for higher breakdown voltage, typically offering superior avalanche robustness above 500V. The IPP50R190CEXKSA1 (500V, CoolMOS™ CE) utilizes superjunction technology, emphasizing a balance between low conduction loss and switching efficiency. If the actual peak operating voltage consistently exceeds 450V, maintaining sufficient voltage margin is advised, favoring the former device. 2. On-Resistance & Drive Characteristics The IPP50R190CEXKSA1 features a slightly lower Rds(on) (190mΩ vs. 192mΩ), but its specified condition is at Vgs=13V; it may perform better than the STP18N55M5 under a 10V drive in practice. Its maximum Vgs(th) is lower (3.5V vs. 5V), making it more sensitive to gate noise—ensure the turn-off voltage remains ≤2V. 3. Dynamic Parameters & Switching Performance The Qg of the IPP50R190CEXKSA1 is 52% higher (47.2nC vs. 31nC), increasing gate drive loss at the same frequency; verify the existing drive circuit’s current capability. While Ciss is similar, the Miller plateau characteristics of CoolMOS™ CE may differ, requiring validation of switching ringing and EMI performance. 4. Thermal Design & Power Limits The IPP50R190CEXKSA1 has a slightly higher Pd (127W vs. 110W), but both use TO-220 packages; actual thermal resistance depends on internal bonding and heatsinking design. Infineon’s PG-TO220-3 may offer improved mechanical strength in the insulating spacer. 5. Operating Temperature Range The IPP50R190CEXKSA1 supports a lower starting temperature of -55°C, making it suitable for industrial wide-temperature environments. The STP18N55M5 does not specify a lower limit; while -55°C is typically assumed, detailed datasheet specifications should be confirmed. Replacement Recommendation: Substitution is feasible in applications where input voltage ≤400V, gate drive capability is sufficient (can provide 13V/≥2A peak), and switching frequency ≤50kHz. However, switching losses and system efficiency at elevated temperatures must be re-evaluated.