Single-cell Li-ion fuel gauge with Impedance Track™
It communicates over an I²C interface, making it a straightforward add-on for a host MCU that needs accurate remaining-capacity data without running coulomb counting in firmware. The 9-DSBGA package (9-UFBGA, DSBGA) is a small 0.4 mm pitch BGA — fine for compact portable designs, but not something you want to hand-solder in the field without a rework station and magnification.
The Impedance Track™ algorithm self-learns battery impedance over temperature and age, so the gauge stays honest through winter and summer without a calibration cycle. If your system lives inside a conditioned building (0°C to 70°C), you still get the headroom — no issue.