Zener TVS for 15.3 V rail protection
The 1.5KE18AE3/TR13: The 1500 W rating is the nominal peak pulse power at 25 °C; derate linearly above that per the datasheet's power-derating curve. For a 12 V or 15 V DC bus in industrial or telecom gear, this part absorbs the surge without letting the downstream regulator see more than 25.2 V.
Obsolete — sourcing through surplus channels
Microsemi has marked the 1.5KE18AE3/TR13 as obsolete. The DO-201AA (DO-27) axial-lead package is a standard footprint; a replacement TVS with the same package and similar clamping voltage can be sourced, but a pin-compatible cross-reference from Microsemi is not published. A board-spin evaluation is advisable if the original part is no longer obtainable.
Package and temperature range
Operating junction temperature spans -65 °C to +150 °C, covering the full industrial and military temperature envelope.