Impedance Track™ fuel gauge for single-cell Li-ion packs
The BQ27421YZFT-G1D: It targets portable devices where accurate remaining-capacity estimation matters more than a simple voltage-based gauge — think handheld medical instruments, IoT sensors, and consumer electronics that run on a 1S Li-ion pack.
Single-cell constraint — no 2S support
This part is rated for exactly one Li-ion cell. It does not support 2S or higher series stacks.
Package and footprint — 9-DSBGA
The 9-DSBGA package requires a controlled solder-paste stencil and a reflow profile matched to the small bump size. No exposed thermal pad — heat dissipation is through the bumps and the board copper.
Temperature grade covers portable and indoor industrial
Not rated for under-hood automotive or high-temperature industrial enclosures.