A low-power low-voltage NMOS bulk-mixer with 20 GHz bandwidth in 90 nm CMOS

A fully differential low-voltage mixer topology is presented. The problem of stacking input-, cascode- and switching-transistors within 1.2 V supply voltage is solved by the use of a bulk driven mixer core. In order to demonstrate the feasibility a testchip was manufactured in INFINEON triple well 90 nm standard CMOS process. The differential mixer includes an on-chip resistive 50 Q termination and an operational amplifier for measurements. The chip features a gain of 3.2 dB. a DSB noise figure of 17.4 dB, an input IP3 of -2.1 dBm. an input 1dB compression point of -13.3 dBm and consumes 1.8 mW at a power supply voltage of 1.2 V. The mixer has a 3 dB low-pass bandwidth of 20 GHz.