What the 1N6377RL4 protects and how it works
The 1N6377RL4 is a unidirectional Zener TVS diode from onsemi's Mosorb™ series, designed to clamp voltage transients on a 15V nominal rail. Its reverse standoff voltage is 15V, meaning it stays off during normal operation. When the line sees a surge, breakdown occurs at a minimum of 17.6V, and the diode clamps the peak to 25V while absorbing up to 1500W of peak pulse power. That 1500W rating is the 10/1000 µs waveform — enough to handle inductive kickback, lightning-induced spikes, or load-dump events in industrial and automotive auxiliary circuits.
onsemi lists the 1N6377RL4 as Obsolete. For BOM lines that still call out this exact order code, the only sourcing path is through independent distributors who hold existing stock or can locate inventory from surplus channels.
Package and mounting — DO-201AD axial leaded
The 1N6377RL4 comes in a DO-201AD axial package, a through-hole form factor with two wire leads. It mounts by inserting the leads into plated through-holes on the PCB and soldering.