Single-cell Li-Ion guard with integrated fault detection
The Texas Instruments BQ29728DSET is a single-cell Li-Ion/Polymer battery protection IC that monitors over-current, over-voltage, under-voltage, and short-circuit conditions. It sits between the cell stack and the load/charger, pulling the discharge FET gate low when any fault threshold is crossed — a standard safety architecture for portable electronics and power-tool packs.
Protection scope and what it covers
The fault-protection block covers over-current, over/under-voltage, and short-circuit — the four failure modes that account for nearly all Li-Ion cell damage in the field. Over-voltage detection prevents charger runaway; under-voltage blocks deep discharge that degrades cycle life. The current-sense comparator triggers on both over-current (load fault) and hard short (cell tab or output short), with separate thresholds and response times. Rated for a single cell (1s) only — do not cascade for multi-cell stacks. The BQ296217DSGT covers 2-4 series cells but with a narrower protection set (over-voltage only), so the BQ29728DSET is the correct choice when you need the full fault suite on a single-cell rail.
Housed in a 6-WFDFN (6-WSON 1.5x1.5) package — a 1.5 mm square, 0.75 mm max height, 0.5 mm pitch. The 6-pin footprint routes easily on two-layer boards.
Active production and sourcing
Sourced through authorized distribution channels; the date-code and marking consistency can be verified against TI's factory traceability. No second-source cross-reference is maintained; the BQ296217DSGT is a different protection scope (multi-cell, over-voltage only) and is not a pin-compatible drop-in.