Single-cell Li-ion linear charger, 250 mA ceiling
The BQ25100YFPR is a Texas Instruments single-cell linear charger for Li-ion/Polymer batteries, delivering a programmable charge current up to 250 mA and a fixed battery pack voltage of 4.2V. The constant-current / constant-voltage profile is standard for Li-ion charging, and the 250 mA limit makes this part a fit for small-capacity cells in wearables, hearables, and portable medical devices where the charge current must stay within the battery's safe C-rate.
Charge current programmable, protection built in
The charge current is constant and programmable via an external resistor — no I2C bus needed, which keeps the BOM simple for low-pin-count designs. Fault protection covers over-temperature, over-voltage, and short-circuit, so the charger can handle a misbehaving cell or a fault on the input rail without external clamp diodes. The supply voltage max is 6.45V, which means a standard 5V USB rail or a 5V wall adapter will work, but a 6V rail is the practical ceiling before the internal LDO drops out.
Active production, 6-DSBGA package
This is a 0.4 mm pitch wafer-level chip-scale package; the PCB land pattern must follow the TI recommended footprint for the DSBGA, and the assembly house needs experience with fine-pitch BGA reflow.