A precisely gain controlled RF front end for T-DMB tuner ICs

Abstract

A precisely gain controlled RF front end is developed for T-DMB tuner IC applications. A precise RF gain control with 50dB dynamic range is achieved in RF VGA by employing a capacitive ladder type attenuator. The proposed method enables us to design and analyze very fine gain step VGA concretely. Implemented in 0.13µm CMOS, the tuner RF front end consumes 9.7mA at 1.2V supply. Measured results are NF < 1.5dB at the maximum gain and the accurate 1dB gain step is obtained.