Clamping voltage and standoff margins
The 1.5KE39AHA0G: Reverse standoff voltage is 33.3V typ — the rail sits below this during normal operation, so the diode draws only leakage current. The breakdown voltage range starts at 37.1V min, giving a guard band before the device starts conducting. A downstream 60V-rated DC-DC converter or load-dump clamp has margin above this clamp level. Power line protection is marked as 'No' — this is a unidirectional Zener TVS, not a bidirectional or steering-diode array, so it clamps one polarity only and is intended for DC rails, not AC mains.
Active production — sourcing posture
The base product number 1.5KE39 covers the full family; the 'A' suffix denotes the tighter breakdown tolerance variant.