What this Zener TVS protects and where it fits
The 1.5KE43ARL4 is a unidirectional Zener transient-voltage suppressor from the onsemi Mosorb™ family, rated for 1500W peak pulse power (10/1000µs waveform). It clamps a transient at 59.3V maximum when the surge current reaches 25.3A, with a reverse standoff voltage of 36.8V – meaning the protected rail should stay below that DC level to avoid leakage. The DO-201AD axial-lead package is through-hole mounted, suited for general-purpose board-level transient protection where a soldered lead provides mechanical robustness over surface-mount alternatives.
Breakdown voltage, clamping, and operating range
Minimum breakdown voltage is 40.9V, which means the device starts conducting (and thus protecting) once the transient exceeds that threshold. The clamping voltage at peak pulse current is 59.3V – the maximum voltage the protected circuit will see during a surge event. Operating junction temperature spans -65°C to 175°C, covering most industrial and automotive under-hood environments without derating concerns at the high end.
Obsolete – last-time-buy and sourcing reality
onsemi has marked the 1.5KE43ARL4 as Obsolete.