Package and board-fit for the 16-WQFN
The BQ25302RTER comes in a 16-WFQFN Exposed Pad package (3x3 mm body, 16-WQFN supplier device package). The 0.5 mm pitch QFN demands a solder-mask-defined pad and a via array under the thermal pad; a 2-layer board can handle the thermal dissipation if the copper pour on the bottom layer is stitched through.
Charge current ceiling and protection coverage
Rated for a maximum charge current of 2A, programmable via an external resistor — the constant-current phase is set by the resistor value, not by a fixed internal reference. The battery pack voltage terminates at 4.4V, which suits standard single-cell Li-Ion and Li-Polymer cells with a 4.4V charge ceiling. The input supply maximum is 6.2V, so a standard 5V USB bus or a 5V wall adapter sits well inside the operating range without an external clamp. Fault protection covers overcurrent, overvoltage, and short-circuit conditions — the device latches off or cycles on a fault, which removes the need for a separate protection FET in most single-cell portable designs.
USB interface and temperature grade
The USB interface means the charger negotiates the input current limit per the USB BC1.2 spec or a simple D+/D- detection scheme — the actual limit is set by the external resistor, not by the interface itself. The charge current must be derated above 85°C ambient per the thermal foldback curve; the QFN package's thermal pad keeps the junction below the 125°C limit at 2A charge in a 25°C ambient with a proper PCB land.