A 30-Gb/s, 2 × 6-bit I/Q RF-DAC transmitter with 19.9 dBm in the 20–32-GHz band

Two ultra-broadband, multi-standard 20–32-GHz and 1–32-GHz I/Q RF-DAC digital wireless transmitters are proposed for 5G terminals as a replacement of the traditional transmitter architecture with baseband DAC, linear up-convert mixer and linear PA driver. They feature a process-and-temperature invariant quadrature phase generator with less than 1.4° phase error from 1 to 32 GHz, and a series-stacked large power, gate-segmented output stage with multi-level amplitude modulation. The tuned 45-nm SOI CMOS transmitter prototype with transformer-coupled output stage achieved 19.9 dBm output power with record data rates of up to 30 Gb/s and 24.6 pJ/b efficiency in the 20–32-GHz range using QPSK, 16QAM, 32QAM and 64QAM modulation formats.