Single-cell Li-Ion charger with I²C control
The Texas Instruments BQ24151YFFR is a single-cell Li-Ion/Polymer linear battery charger delivering up to 1.25 A charge current with I²C-programmable current, voltage, and timer settings. The maximum battery pack voltage is 4.44 V, matching the termination voltage for standard Li-Ion and Li-Polymer cells. Fault protection includes over-temperature and over-voltage shutdown, and the constant-current charging profile suits single-cell portable designs. The 20-bump DSBGA package (0.4 mm pitch) requires a controlled PCB layout — the small footprint is an advantage in space-constrained handheld devices but demands careful fan-out and thermal vias under the die.
The DSBGA package demands a solder-paste stencil aperture matched to the 0.4 mm pitch — typical reflow profiles for SAC305 alloy apply, with a peak temperature around 260°C. A moisture bake (MSL level not confirmed) may be needed if the parts have been stored beyond the floor-life. The I²C interface operates up to 400 kHz standard mode; pull-up resistors to the 1.8 V or 3.3 V logic rail must be sized for the bus capacitance and rise-time requirements.