What this 1-cell charger delivers on the power rail
The BQ25611DRTWT is a single-cell Li-ion/Polymer charger IC from Texas Instruments, rated for a 3.2 A maximum charge current with a programmable constant-current profile via the I²C bus. The 3.2 A ceiling means a 2000 mAh cell can fill in under 40 minutes at the full rate, but the thermal budget in the 24-WQFN package demands a solid thermal via pattern under the exposed pad. Input supply tolerance goes up to 13.5 V, so a 5 V USB port or a 9 V adapter is fine, but a 12 V rail sits right at the edge — the designer should verify the absolute maximum rating in the datasheet before committing the BOM.
Parametric fit for the battery and system
The battery pack voltage range is 4.6 V to 5.15 V, which covers the standard 4.2 V Li-ion termination voltage plus a small constant-voltage taper window. The charger terminates when the current drops below the programmed threshold, not at a fixed voltage — the I²C register sets the timer and current limit. Fault protection is built in for over-current, over-temperature, and over-voltage events, so the host MCU does not need to monitor charge status continuously.
ROHS3 compliant.