Analysis and Design of Multistage Low-Phase-Noise CMOS LC-Ring Oscillators

Abstract

A novel CMOS LC oscillator architecture combining an LC tuned oscillator and a ring structure is presented as a new design topology to deliver improved phase noise for multiphase applications. The relative enhancement in the phase noise is estimated using a linear noise modeling approach. A three-stage LC-ring oscillator fabricated in a 0.6 mm CMOS technology achieves measured phase noise of -132 dBc/Hz at 600 kHz offset from a 900 MHz carrier and dissipates 20 mW with a 2.5 V power supply.