A Fully Integrated 2.4GHz BLE Transmitter with ADPLL and Class-G Switched-Capacitor PA Achieving 30% System Efficiency

This work proposes a 2.4-GHz Bluetooth Low-Energy (BLE) transmitter that delivers high output power with high system efficiency. The chip is fabricated in a 40-nm CMOS process and occupies a chip area of 0.56 mm², integrating a divider-less all-digital phase-locked loop featuring a Class-C digitally controlled oscillator and a DTC–assisted TDC, and a single-ended Class-G switched-capacitor power amplifier with enhanced coding to improve power back-off efficiency across a wide output range. The transmitter supports −24 dBm to +8.15 dBm output power and achieves 30.39% peak system efficiency at +8.15 dBm while satisfying BLE emission mask requirements.