Zener TVS for 150V rail protection
This is a unidirectional device, so it protects one polarity; for AC or bidirectional rails you would need two devices back-to-back or a dedicated bidirectional TVS.
DO-214AA SMB footprint and tape reel
Surface-mount DO-214AA (SMB) package — the same footprint as the common SMBJ series, so if your BOM already has an SMBJ part at a different voltage, the pad layout is a drop-in swap. The Tape & Reel (TR) suffix means it ships on 13-inch reels, standard for pick-and-place assembly.
Active production — supply posture
The base product number SMBJ150 is a standard catalog item, so stock rotation across distributors is typically healthy.