A 29.6 dBm, 47.96% DE Intra-Cell IQ Generation SCPA Using Time-Domain Charge Redistribution

In this paper, a direct intra-cell in-phase/quadrature (IQ) generation switched-capacitor power amplifier (SCPA) using time-domain charge redistribution is proposed. Such a direct intra-cell IQ generation synthesizes an intermediate voltage level by strategically interconnecting differential capacitor cells. The generated three-level waveform enables IQ vector synthesis using standard 50%-duty-cycle clocks and theoretically minimizes dynamic switching losses. Fabricated in a conventional 40-nm bulk CMOS, the prototype SCPA achieves a peak output power of 26.68 dBm with 43.93% drain efficiency (DE) in IQ-combined mode. Meanwhile, it delivers 29.6 dBm peak power and 47.96% DE in only-I mode. For a 30 MHz 64-QAM signal, the SCPA achieves 23.01 dBm average output power with an EVM of 5.04% and an ACLR ≤ –31.9 dBc.