1.5 A charge current and USB input — what drives the BOM fit
The BQ24030RHLRG4 is a single-cell Li-Ion/Polymer linear charger IC from TI's bqTINY™ III family, delivering a programmable constant charge current up to 1.5 A from a USB or adapter input rated to 16 V.
Programmable current and timer — design-in decisions
Charge current and safety timer are programmable via external resistors, giving the designer control over charge profile without firmware. The constant-current phase is set by a single resistor to ground; the timer terminates charging if the battery does not reach the 4.2 V full-charge threshold within the programmed window. Fault protection is built in: over-temperature, reverse current, and short-circuit protection are on-chip, eliminating the need for external supervisory components in most single-cell portable designs.
Package and thermal — layout checklist
The 20-VFQFN with exposed pad (3.5x4.5 mm) requires a thermal land pattern on the PCB with multiple vias to the ground plane. The exposed paddle is the primary heat path; without adequate copper area the 1.5 A charge current will push the die above the 125°C junction limit in ambient above 50°C.