A very low distortion down converter for a W-CDMA was developed. A LO amplifier is constructed with a differential amplifier and transistors which operate as a push-pull driver amplifier. As this LO amplifier has faster switching time of the differential pair, the down converter achieved a low noise figure (NF) performance. In addition, the low output impedance of the LO amplifier leads to lower supply current without using the LO buffer circuit. Insertion of a resistance between the bases of the transconductance stage of the mixer circuit realized low distortion without a degradation of the noise figure of the down converter. The down converter in SiGe-BiCMOS process achieved conversion gain of 11.0 dB, NF of 8.8 dB and IIP3 of +3.5 dBm with 7.4 mA current consumption, 2.8 V supply voltage.