Highly-linear CMOS cross-coupled compensator transconductor with enhanced tunability

Abstract

Proposed is the design of a CMOS highly-linear differential cross-coupled compensator transconductor that combines both cross-quad and cascomp linearisation techniques with enhanced tunability. The proposed cross-coupled compensator linearises the total drain current while maintaining a high input voltage swing range. It achieves a wide tunable nulling over 500 mV differential input signal and a tunable 50% increase in gm flatness. The proposed linearised transconductor achieves a measured 20 dB IM3 distortion reduction after linearisation. The linearised transconductor enhanced tunability technique achieves IM3 better than -78 dBc at 1 GHz at an optimum bias condition with ease and precision without reducing the linear signal handling capability, thus improving the overall transconductor dynamic range performance.