A CMOS VCO with 48% tuning range for modern broadband systems

This paper presents a CMOS VCO in a 0.35 /spl mu/m process which achieves a tuning range of 2.8 GHz-4.55 GHz and phase noise of -142dBc/Hz at 3 MHz offset (from a 1.8 GHz carrier). 5-bit digital coarse-tuning and accumulation-type MOS varactors allow for a 48% tuning range. An integrated regulator provides low supply pushing (100 kHz/V), reduces AM-to-PM sensitivity from the supply, and ensures optimum operation on multi-band/multi-standard single-chip transceivers with simultaneous operation. A model for the hand analysis of VCO noise is presented giving excellent agreement with measurements.