32-QFN footprint and board integration
The BQ25720RSNR comes in a 32-WFQFN exposed pad package, supplier device package 32-QFN (4x4 mm). The exposed pad on the underside must be soldered to a thermal land on the PCB — the datasheet's recommended layout ties it to the ground plane for heat spreading. Without a proper via array under the pad, the junction temperature rises faster than the 125°C TJ max allows under sustained 16 A charge current. Mounting type is surface mount, so the part feeds from tape-and-reel or cut-tape. For a kitting lead planning a reel changeover, the 32-QFN is a standard 4×4 mm body — no special feeder required on a typical pick-and-place.
16.256 A charge current and chemistry flexibility
Maximum charge current is 16.256 A, programmable via SMBus — that is a high ceiling for a buck-boost charger in a 4×4 mm QFN. The constant-current loop is programmable, so the actual charge rate is set by the host controller, not fixed by the part. Battery chemistry support covers lead-acid, Li-Ion/Li-Polymer, LiFePO4, NiCd, NiMH, and SuperCap — one BOM line for multiple product variants without swapping the charger IC. The voltage-programming feature and the 24 V max battery pack voltage mean it handles 1 to 4 series cells, with the supply input up to 26 V.
The base product number BQ25720 covers the family; this RSNR suffix is the 32-QFN tape-and-reel variant.