A 45- to 64-GHz ultra-low-power and low-LO-power sub-harmonic down-conversion mixer with merged self-biased trans-impedance amplifier in 90-nm CMOS

A 45- to 64-GHz ultra-low-power single-ended sub-harmonic down-conversion mixer with a merged structure fabricated in 90-nm CMOS process with triple-well NMOS devices is presented. The mixer core is merged directly with self-biased trans-impedance amplifier (TIA) to omit its traditional load stage and to enhance the conversion gain. By using weak-inversion bias technique in a source-driven topology, the mixer core only needs quiescent current of μA which can be supported from TIA via the feedback resistor. The sub-harmonic mixers can work effectively for millimeter wave (MMW) system by employing local oscillator (LO) frequency that is only half of the fundamental mixer. When operating with the optimal low LO power of −3.5 dBm at 30 GHz, the mixer exhibits a maximum conversion gain (CG) of 6.4 dB and 2 LO-to-RF isolation higher than 46.5 dB from 45 to 64 GHz. The total power consumption is 1 mW at 0.8 V. The calculated figure of merits (FOM) with the consideration of CG and power consumption is excellent among the reported mixers operating at V-band in CMOS process.