Single-cell Li-Ion fuel gauge with HDQ bus
The BQ26220PW is a dedicated battery monitor IC for single-cell lithium-ion packs, communicating over Texas Instruments' proprietary HDQ single-wire interface. It tracks charge and discharge activity to report remaining capacity, voltage, and temperature-compensated state-of-charge — the HDQ bus keeps the pin count to 8 in the TSSOP package, which simplifies the layout for space-constrained handheld designs.
Housed in an 8-TSSOP (4.40 mm width) with a tube shipment format, the BQ26220PW mounts on the PCB with standard surface-mount reflow profiles — no exposed pad to solder, so the thermal relief is through the leads alone.
ROHS3 compliant, with no REACH or UL certification noted in the available documentation; the HDQ interface requires a dedicated host port, not a shared I2C bus, so factor that into the microcontroller selection.