A RF front-end for digital audio broadcasting

A band 3 receiver RF front-end for digital audio broadcasting (DAB) is described in this paper. The front-end integrates most of the functions necessary to receive and down convert band 3 (174~245MHz) signals for further baseband processing, including a variable gain LNA, mixers, VGA, IF amplifiers, and PLL. The overall receiver gain is >90 dB and NF is 4 dB. Gain can be controlled over a range of over 95 dB and IM3 remains above 60 dB up to input levels of -10 dBm. The linearity and dynamic range of this system is improved by using an external attenuator that has 30 dB variable attenuation. Two AGC circuits (one for the RF part and another one for the IF part) are implemented in this receiver. An on-chip PLL based on integer-N architecture with P and S dividers is designed with integrated VCO generate all the LO frequencies. The prescaler used in the PLL realizes a divide- by-64/65 stage. The front-end is designed in a standard 0.18 mum CMOS process. The power consumption from a 3.3 V power supply is 75 mA.