A 2.4-GHz Reconfigurable Digital Transmitter with Three-Vector-Synthesized IQ-Shared PA and Envelope Rotation Calibration for Multi-Standard IoT Applications

A fully integrated multi-standard digital transmitter featuring linearity enhancement is demonstrated, incorporating a reconfigurable digital modulator to support OOK/BPSK/QPSK/16-QAM multi-modulations and an on-chip envelope rotation calibration circuit to optimize the linearity of 16-QAM modulation. This architecture also employs a three vector-synthesized (TVS) IQ-shared Class-E power amplifier to avoid the 3 dB power loss of IQ transmitter and the mismatch between amplitude modulation and phase modulation paths of polar transmitter, achieving high efficiency and high linearity. Implemented in 40 nm CMOS， it achieves 35.7% peak system efficiency (SE) with 5.08 dBm peak output power at 2.4 GHz and occupies a core area of only 0.15 mm2. At a data rate of 8 Mbps, the EVM of 16-QAM modulation is optimized from -19.9 dB to -24.2 dB through envelope rotation calibration with an average SE of 19.1%, an average output power of 2.58 dBm, and an energy efficiency of 1.18 nJ/bit.