Single-cell Li-Ion linear charger in a flip-chip package
The STMicroelectronics STBC15LJTR is a linear battery charger IC for single-cell Lithium-Ion packs. It terminates at 4.4 V and delivers a programmable charge current up to 40 mA — a ceiling that places it squarely in the coin-cell, wearable, or small IoT-sensor charging tier, not in tablet or power-bank territory. The USB interface and constant-current / constant-voltage profile are standard for the class; the programmable features (current, voltage) let you dial in the exact charge curve for the cell. Fault protection covers reverse-current blocking, so a fully charged cell won't back-drive the supply when USB power drops.
The 40 mA maximum charge current is the fit gate. It terminates at 4.4 V.