EFR32BG29B220F1024CJ45

The EFR32BG29B220F1024CJ45 packs the BG29 Bluetooth LE platform into a 2.6 mm x 2.8 mm WLCSP-45, the smallest package in this group, for wearables and miniaturized sensors where board area is the binding constraint. The core matches its siblings — a 76.8 MHz Arm Cortex-M33, 1024 KB of flash, 256 KB of RAM, Bluetooth 5.4 with LE Long Range and 2M PHY, and Secure Vault High — but the B220 variant is built around a boost DC-DC converter, so the radio runs directly from a 1.2 V to 1.7 V single-cell source without an external regulator. Transmit power is +4 dBm, GPIO count is 19, and the operating range is -20 °C to +55 °C, reflecting the consumer-battery applications it targets. The DC-DC's integrated coulomb counter still reports charge consumption for battery gauging. Selection note: choose the B220 only when the WLCSP footprint and single-cell boost input are both required, and confirm your assembly house handles wafer-level packages; for industrial temperatures or easier QFN assembly, the B140 and B230 codes are the practical alternatives. Parameters verified against Silicon Labs documentation.