A 2.4GHz low phase noise frequency synthesizer for WiMAX applications

Abstract

This paper presents a low phase noise frequency synthesizer for WiMAX applications. The operating frequency of the proposed design ranges from 2.2GHz to 2.4GHz with a 1.25MHz spacing for the 1.25MHz to 40MHz channel bandwidth. The proposed VCO suppresses the phase noise effectively by adopting the Q-enhancement technique, the memory reduced tail current, and a noise filter. The high speed frequency divider is implemented by an improved TSPC D-flip-flop. The proposed design is fabricated in a TSMC 0.18µm CMOS 1P6M process. The measured phase noise is -118Bc/Hz at an offset of 1MHz from the center frequency. The fabricated chip consumes 25.5mW with a 1.5V supply and occupies a 1.1mm² die area.