A 1.0–7.0 GHz inductorless RF mixer with multiple feedback and active load in 40-nm CMOS

In this paper, a 1.0–7.0 GHz inductorless RF wideband active down-conversion mixer is presented. The mixer is a modified double-balanced Gilbert-type structure. The capacitive cross-coupling (CCC) and positive feedback topology are employed in the common-gate (CG) RF stage. Common-mode feedback (CMFB) is incorporated in the load stage. It acts as an active load to improve the linearity. For output matching and testing purposes, an intermediate frequency (IF) balun is also designed. A prototype of proposed mixer is implemented in standard SMIC 40-nm COMS technology. The core only occupies 0.02 mm
²
without using any on-chip inductors. Postlayout simulation exhibits a conversion gain of 13.2 dB at the IF of 50 MHz. The gain variation is less than 2.0 dB from 1.0 to 7.0 GHz. The minimum SSB NF is 9.1 dB at 1.0 GHz. An input matching (S11) of less than −10.0 dB is achieved over entire RF band. The IIP3 is −10.9 dBm at 7.0 GHz. The total power consumption is 3.1 mW at 1.1 V DC power supply.