2S Li-Ion over-voltage watchdog
The Texas Instruments BQ29209DRBT is a dedicated battery protection IC for two-cell (2S) Lithium-Ion packs, providing over-voltage fault protection. It monitors each cell independently and triggers a protective action when any cell exceeds its over-voltage threshold. This is a single-function protector — it does not handle over-current, short-circuit, or temperature faults, so the BOM needs additional protection layers for a fully safeguarded pack.
Housed in an 8-SON (3x3 mm) package with an exposed pad, this is a bottom-pad QFN-style part. The exposed pad under the IC is the main thermal path and also the ground connection.
Rated from -40°C to 110°C ambient, this part handles industrial battery packs, outdoor telecom backup, and power-tool applications. It stops short of automotive under-hood environments (125°C), so if the design targets a passenger-cabin BMS or an engine-bay pack, look at the AEC-Q100 graded BQ79612PAPRQ1 instead.