The 1.5SMC200A: This voltage window — 171 V normal operating, 190 V guaranteed breakdown, 274 V clamp — defines the protected rail: a 150 V or 170 V bus sees no leakage at steady state, but the diode conducts before the rail exceeds 190 V and holds the transient below 274 V.
Active production — no end-of-life watch needed
Littelfuse lists the 1.5SMC200A as Active. No NRND, no last-time-buy, no successor to track.
Package and board-fit: DO-214AB (SMC)
Supplied in DO-214AB (SMC) surface-mount package, also referenced as SMCJ. Operating junction temperature range is -55°C to 150°C, covering industrial and outdoor equipment without derating.