A wideband RF amplifier for satellite tuners

This paper presents the design and measured performance of a wideband amplifier for a direct conversion satellite tuner. It is composed of a wideband low noise amplifier(LNA) and a two-stage RF variable gain amplifier(VGA) with linear gain in dB and temperature compensation schemes. To meet the system linearity requirement, an improved distortion compensation technique and a bypass mode are applied on the LNA to deal with the large input signal. Wideband matching is achieved by resistive feedback and an off-chip LC-ladder matching network. A large gain control range(over80 dB) is achieved by the VGA with process voltage and temperature compensation and dB linearization. In total, the amplifier consumes up to26 mA current from a3.3 V power supply. It is fabricated in a0.35-μm SiGe BiCMOS technology and occupies a silicon area of0.25 mm2.?2011 Chinese Institute of Electronics