A 12 bit split-array switched capacitor power amplifier in 130nm CMOS

This paper presents a 12 bit split-array switched-capacitor power amplifier (SA-SCPA) to improve resolution of an SCPA and hence the linear dynamic range. An attenuation capacitor added between two sub-arrays allows a smaller ratio between the smallest and largest capacitors in the array, accommodating better matching. To compromise between efficiency and linearity, 4 binary bits are chosen for the LSB sub-array and 4 binary + 4 unary bits are chosen for the MSB sub-array. The SA-SCPA is designed and extracted, in a 130nm RF CMOS technology. It delivers a peak output power of 22.6dBm with a peak PAE of 30%. The linearity of the array is simulated using a 64 QAM, OFDM signal with 20 MHz bandwidth and the EVM is 3.8% while meeting the spectral mask.