Transient protection for a 15.3 V rail
The Littelfuse 1.5SMC18 is a Zener-based transient voltage suppressor (TVS) from the 1.5SMC series, designed to clamp overvoltage transients on a 15.3 V nominal rail. The DO-214AB (SMC) package is a standard surface-mount footprint for TVS diodes in this power class, with a low-inductance body that minimizes clamping overshoot. The -55°C to 150°C junction temperature range means it can sit near a hot power supply or in an outdoor enclosure without derating prematurely.
Obsolete — sourcing through independent channels
Littelfuse lists the 1.5SMC18 as Obsolete. No official successor order code is recorded, so a pin-compatible drop-in from the same manufacturer is not guaranteed. The part is available through independent surplus and broker channels, sourced to order against a BOM line.