Linear 1-cell Li-Ion/Polymer charger in 8-VSSOP
The Texas Instruments BQ2057DGK is a low-dropout linear charger for a single-cell lithium-ion or lithium-polymer battery pack, delivering a regulated 4.1 V charge voltage with a programmable constant-current profile. Housed in an 8-VSSOP package (3.00 mm width, 0.118-inch pitch), it mounts on the board via surface-mount assembly and ships in Tube format — suited for pick-and-place on a standard reflow line.
Charge voltage and current control
The charger terminates at a battery pack voltage of 4.1 V, the standard ceiling for many Li-Ion chemistries that avoids overcharge stress on the cell. Charge current is programmable via an external resistor — the IC itself provides the constant-current regulation loop, so the designer sets the rate by the resistor value alone.
Operating temperature and sourcing posture
Rated for an ambient temperature range of -20°C to 70°C, this covers most indoor portable electronics and consumer equipment — not extended for automotive or military environments.