1 A linear charger for single-cell Li-Ion/Polymer packs
The Texas Instruments BQ24080DRCR is a linear charger IC designed for single-cell lithium-ion and lithium-polymer battery packs. It delivers a programmable charge current up to 1 A, with a fixed 4.2 V battery regulation voltage. The charger operates from a supply up to 6.5 V, making it suitable for 5 V USB or wall-adapter inputs without an external step-down regulator.
Charge current and thermal management in a 3×3 mm package
The 1 A maximum charge current is a practical ceiling for the 10-VSON (3×3 mm) package with exposed pad. At full current the linear regulator dissipates (Vin - Vbatt) × Icharge as heat; a 5 V input charging a 3.7 V cell at 1 A drops 1.3 W across the pass element. The charge current is set by an external resistor (PROG pin), and the safety timer is also programmable via a capacitor on the TIMER pin. This allows the designer to tailor the charge profile to the battery capacity without firmware involvement.
Package and footprint: 10-VSON with exposed pad
The 10-VSON (3×3 mm) package has a 0.50 mm pitch and a large exposed thermal pad on the bottom. The pad must be connected to the PCB ground plane with multiple vias for heat spreading. The surface-mount mounting type requires standard reflow soldering; no special handling beyond moisture sensitivity level (MSL) per the datasheet.