What 190 V standoff means for rail selection
The 5KP190A-HRA: The 190 V reverse standoff (typ) is the working voltage the protected rail can sit at continuously without the TVS conducting — transients above that level get clamped before they reach the load. With a 211 V minimum breakdown and a 310 V maximum clamping voltage at 16.5 A peak pulse, the downstream circuit sees no more than 310 V during a 10/1000 µs surge event.
5 kW peak pulse — what the rating means
The P600 axial body dissipates that energy into the leads and PCB copper; the clamping voltage of 310 V at 16.5 A is the actual let-through the circuit sees during the event.
Temperature grade and the -55 to 175 °C window
-55°C to 175°C ambient operating range puts this in the high-reliability / automotive under-hood bracket — most commercial TVS diodes top out at 150°C, so the extended window covers engine-bay and near Junction environments without derating to the datasheet limit.
What the part is not — power line protection
Power Line Protection is listed as No — this is a point-of-load unidirectional Zener TVS, not a 3-phase mains-rated suppression module. It guards a single rail against transient spikes, not the AC line itself.