A SiGe down-conversion micromixer for wideband-CDMA application

This paper presents a micromixer for WCDMA applications with no external balun requirement. The transconverter cells are applied both to LO and RF port to replace the required baluns for converting the single-ended signal to differential output. Besides providing the function of balun, the transconverter cell also improves the linearity behavior. This benefits the RF input stage especially. This micromixer is realized in 0.35 um SiGe BiCMOS technology. The measured input P1 dB is -12 dBm and IIP3 is 2 dBm. The measured isolations of LO port are all higher than 35 dB. The current consumption of mixer core is about 3.5 mA.