Single-cell Li-ion fuel gauge with Impedance Track
The BQ27411DRZR-G1C from Texas Instruments is a single-cell (1S) lithium-ion battery monitor that uses the Impedance Track™ algorithm to report state-of-charge. Communication runs over an I²C interface, making it a drop-in for portable designs that already have a two-wire bus.
What the 1S cell limit means for your BOM
This part is hard-limited to a single series cell. It cannot be used on 2S or higher battery packs — the internal algorithm and voltage divider assume a single Li-ion cell voltage range. If your design needs a 2S gauge, you need a different part in the BQ274xx family. The Impedance Track algorithm learns the cell's impedance over time, giving more accurate remaining-capacity readings than a simple voltage-based coulomb counter. It is optimised for lithium-ion chemistry and does not support LiFePO4 or NiMH without a different gauge IC.
Package and mounting
Housed in a 12-VFDFN exposed-pad package (also listed as 12-SON 2.5x4mm), this is a no-lead package with a thermal pad underneath. Reflow is the intended assembly method — hand-soldering is difficult without a hot-air station. Cut-tape options are available for prototyping.