A Wideband Digital-Intensive Current-Mode Transmitter Line-Up

Journal article (2023)

Authors

Y. Shen Electronics - EEMCS
M. Hoogelander Tera-Hertz Sensing - EEMCS
R.J. Bootsman Electronics - EEMCS
S.M. Alavi Electronics - EEMCS
L.C.N. de Vreede Electronics - EEMCS
Research Group
Electronics (EEMCS) (TU Delft)
Copyright: © 2023 Y. Shen, M. Hoogelander, R.J. Bootsman, S.M. Alavi, L.C.N. de Vreede
DOI: https://doi.org/10.1109/JSSC.2023.3279235
Digital pre-distortion (DPD)-free Direct-digital RF modulator (DDRM) IQ-mapping Quadrature up-converter Harmonic rejection (HR) Common-gate (CG)/common-base (CB) power amplifier (PA) Current division path Dynamic biasing Radio frequency digital-to-analog converter (RFDAC) TX line-up
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Published Date

2023

Language

English

Reuse Rights

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Faculty

Electrical Engineering, Mathematics and Computer Science

Department

Microelectronics

Research Group

Electronics

Abstract

A current-mode direct-digital RF modulator (DDRM)-based transmitter (TX) architecture is proposed in this article for energy-efficient wireless applications. To demonstrate its key principles, a 2×13 bit demonstrator is implemented in a 40-nm CMOS technology. This DDRM can operate standalone or as a driver for a common-gate (CG)/common-base (CB) power amplifier (PA). The proposed DDRM is based on current-steering radio frequency digital-to-analog converters (RFDACs) that feature an extra current division path to allow the generation of the optimum current-mode class-B drive profile for the final CG/CB PA, facilitating energy-efficient TX operation without compromising linearity. For this purpose, the DDRM uses signed-IQ mapping combined with a class-B harmonic rejection (HR) technique. In addition, an advanced dynamic biasing technique is introduced to further enhance the TX line-up efficiency in deep power back-off (PBO) region. The DDRM driver standalone can provide 19.6-dBm RF peak output power. It supports a '160-MHz 256-QAM' signal at 2.4 GHz with an adjacent channel leakage ratio (ACLR) of -40.3 dBc and an error vector magnitude (EVM) of -33 dB, without using any digital pre-distortion (DPD). When connected to a CB SiGe PA, the overall TX line-up achieves an output power of 27 dBm and an overall TX system efficiency of 20%. This DPD-free TX line-up achieves an ACLR of -37.7 dBc and an EVM of -30 dB, respectively, when operating with an '80-MHz 64-QAM' signal at 2.2 GHz.