An analysis of flicker noise rejection in low-power and low-voltageCMOS mixers

摘要

The sensitivity of RF CMOS receivers using a direct conversion orna low-IF architecture is strongly affected by flicker noise. This paperngives theoretical guidelines to predict the flicker noise innGilbert-cell mixers. The conversion gain, the equivalent input andnoutput noise, and the effect of the pole at the single internal RF nodenare discussed. For the first time, results which are valid in all modesnof operation are given. Such complete results are required for somenultra low-power and low-voltage applications, since the transistorsnmight be operated in moderate or even weak inversion region. Thentheoretical gains are found to remain within a 2-dB margin with respectnto the measurements of a UHF downconverter built in a 0.5 Μm process,nfor a large range of bias conditions and local oscillator swing