SAW-less software-defined radio transceivers in 40nm CMOS

The introduction of several new cellular and connectivity radio standards has attracted the wireless industry to the concept of software-defined radio systems, preferably implemented in advanced nanometer CMOS technology. A first generation of transceivers, using several advances in new circuits and architectures, combined with extensive digital compensation techniques, are indeed able to operate over the complete range of both RF frequencies and baseband bandwidths and as such act like an SDR. However, a real SDR must go further than this. Interoperability and coexistence scenarios, combined with the need to eliminate external fixed-frequency acoustic RF filters, lead to much more stringent requirements on linearity and noise. Therefore, this paper will also present a novel second generation of 40nm CMOS transceivers that enable this. On the TX side, it is crucial to achieve -160dBc/Hz noise level for all possible combinations of RF frequency, baseband bandwidth, and RX-TX duplex spacing. In the receiver, extremely linear circuits are presented, that are able to handle blockers of around 0dBm input level.