Abstract: A direct conversion CMOS DVB-S front-end employs a T-configuration variable attenuator,a single-to-differential low noise amplifier,and a low noise mixer.By innovative use of the attenuator,the linearity handling ability of the system is dramatically improved.The system is designed and fabricated in SMIC 0.18μm RF CMOS technology.The measurement data show that the front-end provides a total of more than 30dB dynamic range and a noise figure of 5dB in the wide frequency signal band.The prototype front-end consumes only 10mA and achieves an IIP3 of +20dBm.

Key words: DVB-S, tuner, wide-band, high linearity