1 A charge ceiling for a single 4.2 V cell
The BQ25050DQCT is a linear charger for single-cell Lithium-Ion packs, with a programmable charge current up to 1 A and a battery regulation voltage of 4.2 V. The 10.2 V supply maximum means it can run from a 5 V USB rail or a 9 V wall adapter without a pre-regulator — the internal pass transistor drops the difference as heat, so the thermal budget at 1 A charge current demands good PCB copper area under the exposed pad.
Package and thermal path
Housed in a 10-WFDFN with exposed pad (3 mm x 2 mm), the part relies on the pad soldered to a PCB copper plane to pull heat out of the die — at 1 A charge current from a 5 V input, the pass transistor dissipates roughly 0.8 W, and the junction-to-ambient thermal resistance depends on the board's copper area, not just the package.
Protection and lifecycle status
On-chip fault protection covers over-temperature and over-voltage conditions — the charger halts the cycle if the die exceeds the thermal limit or the input voltage spikes above the safe threshold.