Single-cell linear charger with 250 mA ceiling
The BQ25100YFPT is a linear charger for single-cell Li-Ion or Li-Polymer packs, terminating at a fixed 4.2 V. The charge current is programmable up to 250 mA via an external resistor — no I²C, no digital interface. The linear topology keeps the BOM small: no inductor, just a few passives and the sense resistor. Built-in fault protection covers over-temperature, over-voltage, and short-circuit conditions. The device enters thermal regulation if the die temperature reaches the threshold, reducing current to keep the junction within the rated 0°C to 125°C range.
Supply range and protection set
Maximum supply voltage is 6.45 V — a standard 5 V USB rail or a 5 V wall adapter works directly, but a 12 V input needs a pre-regulator. The over-voltage protection threshold is set internally; no external divider needed. The charge current is constant-current programmable, not constant-current/constant-voltage with a digital interface. That keeps the pin count low (6 bumps) but means the system cannot dynamically adjust the charge rate during operation — set the resistor once at design time.
Active production status and package options
The 6-DSBGA package requires a controlled reflow profile and a solder-mask-defined pad layout. The small footprint saves board space in wearables and IoT modules.