Low Power Highly Linear Inductorless UWB CMOS Mixer with Active Wideband Input Balun

A low-power, highly linear CMOS double-balanced mixer for UWB applications is presented. The mixer is designed based on well-known folded architecture and also benefits from DC isolation of RF (Radio Frequency) and LO (Local Oscillator) stages. Stacked NMOS-PMOS ${\bf g}_{{\bf m}}$-boosting topology is used in the design of RF stage. To achieve very low power consumption, this stage is biased in sub-threshold region. Also an ultra-wideband active balun is designed and fabricated to generate differential inputs. The balun is separately characterized and its performance is reported both separately and together with the mixer. The design is implemented using 130 nm CMOS process and is operational from 3.1 to 10.6 GHz. The measured maximum conversion gain shows high value of 14.9 dB for the mixer core. Also, the measured double sideband noise figure has a minimum value of 7.8 dB for the mixer core and 12.9 dB when balun is added. Input (RF and LO) port matching is achieved with reflection of more than 10 dB for the entire band. Furthermore, port-to-port isolation is measured that shows excellent isolation between ports. Measured IIP3 as a good indication of linearity performance is also reported and shows excellent linearity that is a result of techniques used in the design. Finally the mixer core area is measured to be 0.056 mm2 with power dissipation of ${\bf 623}\ {\mbi \mu} {\bf W}$ from a 1.2 V supply.