What the protection coverage means for your pack design
The BQ7790518PW is a Li-Ion battery protection IC that monitors 3 to 5 series cells, combining overcurrent, over-temperature, over/under voltage, and short-circuit fault protection in a single 20-TSSOP package. The overcurrent and short-circuit detection thresholds are set internally — no external sense resistor programming — which simplifies the BOM but also means the protection profile is fixed for the part variant. Confirm the trip levels match your cell chemistry and discharge rate before committing the layout.
Package and board-fit considerations
Housed in a 20-TSSOP (4.40 mm width) with surface-mount termination, the BQ7790518PW requires a standard fine-pitch solder reflow profile. The 0.65 mm lead pitch on TSSOP-20 is manageable on a two-layer board with careful fan-out, but a four-layer stack with a dedicated ground plane under the IC improves thermal and noise performance, especially when the pack sees high discharge currents that trigger the protection FETs.