1500 W peak pulse — the energy rating that decides the protection
The 1.5KE220A B0G: That 1500 W figure is the transient energy the part can absorb without failing — for a 328 V clamp, the peak current is 4.8 A. The reverse standoff voltage is 185 V, meaning the diode stays off below that DC rail level and only starts conducting when the transient pushes above the 209 V minimum breakdown threshold.
DO-201 axial-lead — a through-hole footprint that survives rework
The package is DO-201AA (also known as DO-27), an axial-lead through-hole format. The supplier device package is DO-201.
Unidirectional — one channel for DC rail clamping
This is a single-channel unidirectional TVS. It clamps positive transients above the breakdown voltage while blocking reverse polarity — the right choice for a DC power rail (24 V, 48 V, or 120 VDC systems) where the normal operating voltage stays below 185 V. No power line protection is claimed (the part is not designed for AC mains), so it fits secondary-side or low-voltage DC bus protection.