CMOS RF switched capacitor bandpass filter tuned by ring VCO

A new RF switched capacitor bandpass filter and its command circuit made up of a ring voltage controlled oscillator with 'XOR' gates are proposed. Implemented in a standard 0.35μm CMOS technology, this circuit is intended to be used in a subset of professional mobile phone applications [380-520 MHz]. Experiments carried out on a prototype show a tunable center frequency range of 260 MHz [240-500 MHz], with a quality factor that can be as high as 300.