What this Li-Ion charger brings to a portable design
The MAX8903AETI+T is a single-cell Li-Ion battery charger from the Smart Power Selector™ series, handling a 2A max programmable charge current through a USB interface. The charger terminates at a 4.2V battery pack voltage, the standard for Li-Ion cells, and includes over-voltage fault protection to keep the cell from seeing a runaway charge condition. The constant-current charge level is programmable via an external resistor, and a timer provides a backup termination if the current taper doesn't trigger first.
Package and board-fit for hand-soldering
It comes in a 28-WFQFN with an exposed pad (4x4 mm, 28-TQFN supplier package designation). That exposed pad is the main thermal path — you'll want a solid via array under it to the ground plane to keep the die temperature in check at 2A charge current. Surface-mount only, so plan for a reflow profile or a hot-air station.