Behavioral Analysis and Optimization of CMOS CML Dividers for Millimeter-Wave Applications

Current-mode logic (CML) dividers are widely used in radio-frequency and millimeter-wave transceivers and frequency synthesizers for its wide division range. In this brief, a general analysis and optimization methodology of complimentary metal-oxide-semiconductor CML dividers based on the second-order approximation of transconductance is presented for the first time. Mechanisms of asymmetric sensitivity curves around self-oscillation frequency over wideband and inherent cutoff frequency above the self-oscillation are revealed, while corresponding design flow is presented based on the analysis. Following the proposed flow, a better tradeoff between division range and power than the reported arts is obtained by virtue of the proposed optimization method.