Programmable analog frequency divider based on ρ-switching

Abstract

ρ-switching is a technique whereby the topology of an injection-locked frequency divider is changed to make it divide by different values. This paper describes an experimental proof of concept whereby a CMOS LC injection-locked frequency divider with tail injection is switched between two different modes (divide-by-2 and divide-by-4) on the fly. The operation of the circuit is explained qualitatively, verified by simulation and demonstrated experimentally.