Low 1/f noise PMOS resistive mixer

This paper investigates the advantages of using PMOS devices for passive resistive mixer design. The experimental results presented in this paper demonstrate that PMOS mixers offer the advantage of higher signal to noise ratio at very low output frequencies. The significantly lower 1/f noise more than compensates for the higher conversion loss on PMOS mixer as compared to the NMOS mixer. The PMOS and NMOS resistive ring mixers were fully integrated in 0.25 mum CMOS process. Both mixers exhibit very wide-band performance with RF return loss better than -10 dB from 1 to 7 GHz, and high linearity with IP1dB and IIP3 better than 0 dBm and 10.5 dBm respectively over the entire bandwidth. The measured 1/f noise of the PMOS mixer is 6.3 dB lower than that of the NMOS mixer, resulting in over 3 dB better signal to noise ratio at very low output frequencies. This demonstrated the feasibility of using PMOS mixers for low 1/f noise and high linearity applications. In addition, compared to other published CMOS wide-band resistive mixers, both mixers achieve the best linearity over their entire RF bandwidth.