1500W Zener TVS for 171V DC rail protection
The 1.5KE200CABUL: Its 171V reverse standoff voltage means it sits across a 171V DC bus without conducting in normal operation — the rail stays unloaded until a transient pushes past the 190V minimum breakdown threshold.
Clamp voltage and surge current — what the ratings mean for the protected circuit
Every component downstream of this TVS must withstand at least 274V without damage — that includes the bulk capacitor voltage rating, the MOSFET Vds, and the DC-DC converter input. The 274V clamp is the absolute ceiling the TVS holds across the transient; the actual clamp voltage at lower surge currents will be lower, but the BOM must survive the worst-case spec. The bidirectional channel (single) means polarity is irrelevant — the same device clamps positive and negative transients symmetrically. No orientation checks during assembly, and the same part number covers both polarities in a 171V rail.
Temperature envelope and package — where this part fits on the board
Operating junction temperature spans -65°C to 175°C, covering military cold-soak and hot environments near the power supply. No power line protection (no internal filter); this is a pure transient clamp. It responds to an overvoltage event by shunting current to ground, then resets — no reset latency, no leakage after the surge subsides.