8A charge current for multi-cell Li-Ion packs
The Texas Instruments BQ24704RGET is a Li-Ion/Polymer battery charger IC designed for 2 to 4 series cells, delivering a programmable constant charge current up to 8A max. It handles battery pack voltages up to 18V from a supply rail rated to 24V. This part sits in the BQ24704 family and comes in a 24-VFQFN Exposed Pad package (4x4 mm, 0.50 mm pitch).
The 8A max charge current sets the power stage sizing: the external MOSFET, inductor, and sense resistor must handle the peak current without saturating or overheating. The 2-4 cell range means the charger regulates the battery voltage to 18V max — a 4-cell Li-Ion pack at 4.2V/cell hits 16.8V, leaving headroom. The constant-current programmable feature lets you set the charge rate via an external resistor or DAC, which is useful for adjusting charge time vs. battery cycle life. Fault protection covers over-current, over-temperature, and over-voltage — these are integrated, so you don't need external comparators or supervisor ICs for basic protection.
Reworking the 24-VFQFN: what to expect at the bench
The 24-VFQFN Exposed Pad (4x4 mm) is a common QFN package. Under a hot-air station, the pad wicks heat quickly; preheat the board to 100-120°C before reflow to avoid lifting the pad. The 0.50 mm pitch is fine enough that a misaligned part can short adjacent pins, so use a flux-rich rework profile and a good pair of tweezers. Orientation is marked by pin 1 indicator on the package corner — verify it before placement.