Li-Ion battery IC gives load & capacity

The bq27421 Li-Ion battery fuel gauge integrated circuit can extend portable device run-time by 50% or more. The tiny 9-ball 1.5- by 1.5- by 0.5-mm chipscale packaged device accurately reports single-cell battery remaining capacity, state-of-charge, and voltage.

The chip has an integrated 0.007 Ω sense resistor and is easily configures via an I² C interface. It operates from -40° to 85°C using only the cell voltage. Normal current is 93 µA and sleep current is 21 µA, typical. It costs about $1.20 ea/1,000.