A broadband and low cost monolithic BiCMOS tuner chip

Abstract

This circuit is a single chip of a BiCMOS wafer used in cable TV set-top converters;, cable modems, cable TV tuners and digital TVs. It is a double conversion tuner (DCT) structure which has better performance characteristics than the single conversion tuner (SCT). This single chip comprises two LNAs, one AGC, two LO buffers, two VCOs, two resistor-type and double-balanced Gilbert cell mixers, two synthesizers and ESD protection. Its total gain is 45.70 dB, and its total noise figure is 4.3-7.9 dB. The RF varied range, which is not only 50-860 MHz but also 50-1000 MHz, can be applied in cable TV tuners and cable modems. The consuming power is 0.885 W under 3 V and the die size is 4.8 mm(2).