The data rate expected for the forthcoming 5G standard induces stringent constraints for handset transceivers. Wideband carrier aggregation will be handled with flexible and low-power architectures implemented in low-cost technologies. An architecture of a wideband signal generator intended to target sub-6-GHz 5G transmission requirements is presented. The architecture is based on a differential pulse code modulation coding scheme and a custom integrating DAC named the Riemann pump. It performs a 9-dB improvement of the signal-to-noise ratio per doubling of the oversampling ratio while ensuring a flat quantization noise floor over the whole multigigahertz conversion band. Its inherent ability to generate synchronous signals allows us to address carrier aggregation purposes; the generation of 10 synchronized 64-QAM modulated signals between 1.8 and 3.6 GHz is simulated. Postlayout simulations of the Riemann pump implemented in 65-nm CMOS technology fit the exposed theoretical features with a submilliwatt-level power consumption.
['Yoan Veyrac', 'Francois Rivet', 'Yann Deval', 'Dominique Dallet', 'Patrick Garrec', 'Richard Montigny']
A 65-nm CMOS DAC Based on a Differentiating Arbitrary Waveform Generator Architecture for 5G Handset Transmitter