A linearized and low noise CMOS mixer with B-type amplifier-based sub-harmonic balun

A low noise and high linearity down-conversion CMOS mixer for 2.4-GHz wireless receiver is presented in this paper. Using a sub-harmonic balun with a simple but effective B-type amplifier, the local oscillator frequency required for this mixer has been reduced by half, and the input local oscillator signal could be single-ended rather than differential, which simultaneously simplifies the design of local oscillator. A distortion and noise cancelation transconductor in association with current bleeding technique is employed to improve the noise and linearity of the entire mixer under a reduced bias current without compromising the voltage gain. Fabricated in a 0.18-µm RF CMOS technology of Global Foundries, the mixer demonstrates a voltage gain of 15.8dB and input-referred third-order intercept point of 6.6dBm with a noise figure of 2.6dB. It consumes 7.65mA from a 1.0-V supply and occupies a compact area of 0.75×0.71mm2 including all test pads. Copyright © 2016 John Wiley & Sons, Ltd.