Analysis of Nonlinearities in Injection-Locked Frequency Dividers

Abstract

The locking range of injection-locked frequency dividers is investigated and it is shown that the presence of nonlinearities, such as those exhibited in a current mode logic (CML) D flip-flop (DFF)-based divider, can result in a wider frequency locking range. A new approach to evaluate such nonlinearities is described. A new divider topology benefiting from the nonlinearity is presented that exhibits both higher operating frequencies and similar locking range compared to the conventional CML DFF-based topology. The chip was fabricated through a TSMC 90-nm CMOS process.