Wideband CMOS Receivers exploiting Simultaneous Output Balancing and Noise/Distortion Canceling

This paper deals with the problem of realizing wideband receiver front-ends in downscaled CMOS technologies, which are highly wanted for multi-standard radio receivers and cognitive radio applications. Instead of using many narrowband inductor based receivers, we prefer the use of one wideband receiver with sufficient bandwidth to cover all popular frequency bands up to 6 GHz or even 10 GHz. To relax RF filter requirements, high linearity is required, while high gain and low noise are important for good sensitivity. Downscaled CMOS technologies feature high speed transistors, but also decreasing supply voltages and increasing transistor non-idealities, which makes it increasingly difficult to achieve high gain and good linearity. It will be shown that a combination of a common-gate (CG) stage and an admittance-scaled common-source (CS) stage has attractive properties for implementing a wideband receiver with active balun, while simultaneously canceling the noise and distortion of the CG-stage. Example applications in a wideband Balun-LNA and combined Balun-LNA-mixer will be shown.