The Texas Instruments BQ24161BYFFT is a single-cell Li-Ion or Li-Polymer battery charger IC in a 49-bump DSBGA package measuring 2.8 x 2.8 mm. Fault protection covers over-temperature and over-voltage conditions, which is essential for safe Li-ion charging in portable equipment where a runaway cell is a fire risk.
2.5 A charge current — thermal and layout reality
At 2.5 A the power dissipation in a linear charger stage is significant. The DSBGA package relies on the PCB copper and via array to pull heat out of the die. The I²C interface lets you read back die temperature and adjust the charge current dynamically if the thermal budget is tight.
I²C programmability — what it buys you
Unlike a resistor-programmed charger, the BQ24161 lets the firmware set the charge current, termination current, and voltage regulation point over I²C. That means one BOM line can cover multiple battery pack capacities — the same PCB supports a 1500 mAh pack in the low-cost SKU and a 3000 mAh pack in the premium version, with only a firmware change. It also allows the system to reduce charge current when the die or ambient is hot, or when the input supply is weak.
Package and supply voltage
The 49-DSBGA (2.8 x 2.8 mm) is a fine-pitch BGA — the board house needs to handle 0.4 mm or 0.5 mm ball pitch. Maximum supply voltage is 10 V, so a standard 5 V USB input or a 9 V wall adapter is fine; a 12 V rail would need a pre-regulator.
The base product number is BQ24161, so any future PCN or EOL notification would carry that prefix. For dual-sourcing resilience, the I²C programmable nature means a second-source charger with the same register map could be qualified without hardware changes, but TI is the sole source for this exact part number.