A split-array, C-2C switched-capacitor power amplifier in 65nm CMOS

A multiphase RF, C-2C split-array switched-capacitor power amplifier (SCPA) is introduced that allows the resolution and quality factor of the SCPA to be independently controlled. This allows the SCPA to be designed up to the resolution limit of the process, as determined by capacitor matching and jitter in the clock. In prior SCPAs, the resolution was limited by the choice of the output matching network quality factor and the minimum sized capacitor available in the process. A split-array, C-2C SCPA is implemented in 65nm CMOS and occupies 0.85 × 2mm². It delivers a peak output power of 24.05 dBm with a peak system efficiency (SE) of 40.6%. When transmitting a 1.4 MHz, 64 QAM LTE signal it outputs 18.8 dBm at 21.6% SE, with a measured EVM of 2.65 %-rms at 1.8 GHz.