The 1.5SMC56A R7G is a Zener-type transient voltage suppressor from Taiwan Semiconductor Corporation's 1.5SMC series, designed for general-purpose circuit protection. The reverse standoff voltage is 47.8V, and minimum breakdown voltage is 53.2V. This is a unidirectional device — one channel — so it protects a single rail against positive transients. For bidirectional or multi-line protection, you would look at a different part in the same package family.
Supplied in Tape & Reel (TR) — the R7G suffix indicates the reel quantity and packaging code, which matters for automated pick-and-place lines. No power line protection feature is built in; this is a standalone TVS for signal or low-power rail clamping.