A Wideband IQ-Mapping Direct-Digital RF Modulator for 5G Transmitters

This article presents a wideband $2 \times 12$ -bit direct-digital RF modulator (DDRM) operating in 0.5-to-3-GHz band for 5G transmitters. The proposed digital Cartesian features an advanced IQ-mapping technique to boost power by 3 dB and suppress the notation="LaTeX">$I/Q$ image. To verify concept, 40-nm CMOS prototype is implemented whose peak output at 2 GHz more than 14 dBm. It achieves adjacent-channel leakage ratio (ACLR) of −52 dBc error vector magnitude (EVM) −40 20-MHz 256-QAM signal 2.4 GHz. With 320-MHz signal, measured ACLR EVM performances are better −43 −32 GHz, respectively, without using any pre-distortion.