The Texas Instruments bq27421-G1 fuel gauge is a minimally configured microcontroller peripheral that provides system-side fuel gauging for single-cell Li-Ion batteries. The device requires very little user configuration and system microcontroller firmware development. The bq27421-G1 fuel gauge uses the patented Impedance TrackTM algorithm for fuel gauging, and provides information such as remaining battery capacity (mAh), state-of-charge (%), and battery voltage (mV). Battery fuel gauging with the bq27421-G1 fuel gauge requires connections only to PACK+ (P+) and PACK– (P–) for a removable battery pack or embedded battery circuit. The tiny 9-ball, 1.62 mm × 1.58 mm, 0.5-mm pitch NanoFree™ chip scale package (DSBGA) is ideal for space-constrained applications.