The P6KE6V8ARL is a single-direction Zener diode from ST's P6KE TRANSIL™ series, built for clamping transients on a 5.8 V rail. It handles a 600 W peak pulse (10/1000 µs waveform) and clamps at 13.4 V maximum, with a peak pulse current rating of 298 A on the 8/20 µs shape. The DO-15 axial package is through-hole — easy to swap in the field with basic tools, no hot-air station needed.
STMicroelectronics lists the P6KE6V8ARL as obsolete. No official successor is named in the record.
Capacitance and speed — 4000 pF at 1 MHz
With 4000 pF capacitance at 1 MHz, this part is a reasonable fit for DC power rails and low-frequency signal lines. For high-speed data interfaces (USB, Ethernet), that capacitance loads the line — you would typically select a lower-capacitance TVS diode instead. The through-hole package also adds lead inductance that can degrade clamping response on fast edges, so keep the leads short when you install it.