A 1.2 GHz CMOS quadrature self-oscillating mixer

Abstract

This paper presents a quadrature self-oscillating mixer (SOM) that has been fabricated in a 0.6 /spl mu/m CMOS process. The technique used to achieve self-oscillation involves merging the mixer and oscillator functions into a single circuit rather than stacking the two circuits upon one another as has been the approach adopted in previous work. The merging of the two functions is accomplished by modifying the Gilbert cell mixer to output an LO signal component through an additional port which can be fed back to the LO input port to produce oscillation. The SOM dissipates 60 mW at a self-oscillation frequency of 1.2 GHz. As a down-converter, the circuit demonstrates -1 dB of conversion loss with a corresponding input referred third order intercept of -11.5 dBm.