Getting closer to Mitola’s Vision: A 1W, 30dBm, SDR Transmitter with Digital Out-phasing Exponential Modulation in a 65nm CMOS LPE

Abstract A digital pulsed-modulation for high efficiency and linearity, switched-mode power amplifiers (PAs) is proposed. Based on a new representation of digital modulated signals at IF called Out-phasing Digital Exponential Modulation (ODEM), the paper shows the underlying concept, simulations and measurements that predict a faster decaying spectrum, when compared to pulse-width modulation (PWM) Out-phasing, and a power spectrum that fulfills the spectral emission mask even for 64QAM LTE standards. An implementation in a 65 nm CMOS LPE process from GF based on a Class D⁻¹, 30dBm power amplifier, shows that the EVM and SEM requirements for 64-QAM LTE standards are fulfilled. The circuit implementation of the baseband IC as well as the PA is presented. The whole implementation is based on digital circuits.