Design Of The RF Front-end For DVB-S.2 Tuners In 0.18μm CMOS

This dissertation presents the design of the radio-frequency (RF) front-end for the Digital Video Broadcast– Satellite (DVB-S.2) tuners. The proposed direct-conversion RF front end consists of a pseudo-differential low noise amplifier (LNA) and two passive down-conversion mixers.In this dissertation, a brief introduction to the CMOS DVB-S.2 tuners is firstly presented. Following that, a detailed description of the principle and design of the pseudo-differential LNA is given. Derived from traditional narrow band source degenerated structure, the novel LNA proposed in this paper shows a higher gain and a lower Noise Figure (NF) than traditional wideband LNAs. Meanwhile, with a tunable input matching network and load capacitance, the proposed LNA demonstrates a wideband operating frequency range from 950 MHz to 2150 MHz covering the DVB-S.2 band. Moreover, the proposed pseudo-differential LNA implements an active single-ended-to-differential conversion.A passive down-conversion mixer is employed to mitigate the influence of the flicker noise introduced by the mixer itself.The proposed RF front-end is implemented in a TSMC 0.18μm process. Measurement results show that the RF front end has a NF better than 8.8 dB in the operating band with a gain higher than 45 dB. The input-referred 3rd-order intercept point (IIP3) is 12 dBm and the RF front end consumes 33 mA current with power supply of 1.8 V.