Battery monitor for 3-to-14-cell Li-ion packs
The Texas Instruments BQ769142PFBR is a multi-function battery monitor controller designed for 3-to-14-cell series lithium-ion and lithium-polymer battery packs. It integrates over-voltage and under-voltage fault protection, communicates over an I²C interface, and is packaged in a 48-TQFP (7x7 mm) for surface-mount assembly.
Cell-count flexibility and fault protection
The 3-to-14-cell range is the primary selection parameter: a 7-cell pack and a 13-cell pack both fall within the same BOM line, simplifying inventory for a product family that scales stack voltage. The integrated over/under-voltage fault protection means the controller can independently trigger a protection FET or alarm without waiting for the host MCU, which reduces software latency in a fault event.
I²C interface and host communication
The I²C interface is used for configuring protection thresholds, reading cell voltages, and reporting fault status. This is a standard two-wire bus that any MCU with an I²C peripheral can talk to, so no special protocol license or dedicated SPI port is needed. For a firmware engineer, the first-power check is confirming the I²C address and that the bus pull-ups are sized for the bus capacitance of the 48-TQFP package.
Active lifecycle — no EOL risk for new designs
For a BOM cost engineer, this also means dual-sourcing is possible through multiple distribution legs, reducing single-source exposure.
Package and assembly notes
The 48-TQFP (7x7 mm) package has a 0.5 mm pitch, which is inspectable under a standard microscope and reworkable with a hot-air station. The exposed pad on the bottom of the TQFP is the thermal and electrical ground connection; a via stitch under the pad improves thermal dissipation if the controller is running continuous measurements near the 85°C end of the temperature range.
Compatibility with lithium polymer chemistry
The battery chemistry is specified as lithium ion/polymer, so the BQ769142PFBR is directly compatible with lithium polymer pouch cells. The same over/under-voltage thresholds can be configured for the typical 4.2 V/cell full-charge and 2.8-3.0 V/cell cut-off voltages used with LiPo packs. No external level shifting or chemistry-specific front-end is required.