1.5 kW Zener TVS — what it protects and where
The STMicroelectronics 1.5KE15ARL is a unidirectional Zener transient voltage suppressor from the 1.5KE TRANSIL™ series, rated for 1500 W peak pulse power over a 10/1000 µs waveform. It clamps transients at 27.2 V maximum while the reverse standoff voltage sits at 12.8 V, making it a fit for 12 V rail protection in industrial, telecom, and general-purpose DC bus applications. Breakdown occurs between 14.3 V minimum, so the part catches overvoltage events before they reach downstream silicon. The through-hole DO-201AA / DO-27 axial package suits point-to-point wiring or PCB mounting where leaded transient protection is preferred over surface-mount alternatives.
STMicroelectronics lists the 1.5KE15ARL as obsolete.
Ratings that decide the fit
Three voltage numbers gate the application: the reverse standoff of 12.8 V is the maximum DC or peak AC voltage the protected line can carry without the device conducting; the minimum breakdown of 14.3 V is where avalanche begins; and the maximum clamping of 27.2 V at the rated peak pulse current is the voltage the load sees during a surge. The 368 A peak pulse current figure is measured with an 8/20 µs waveform, a common lightning-surge test condition. Capacitance of 5000 pF at 1 MHz matters on signal lines where excessive loading would distort high-speed data.