A Fractional-N Ring PLL Using Harmonic-Mixer-Based Dual Feedback and Split-Feedb

Abstract

A phase-locked loop (PLL) employing a split-feedback divider and nested-PLL-based phase-domain low-pass filter (PDLPF) within the harmonic-mixer (HM)-based dual-feedback architecture is presented in this article. The proposed architecture not only overcomes the noise shaping frequency limitation seen in a conventional dual-feedback PLL, but also solves stability and noise overhead issues that were present in the prior art. Due to the wide loop bandwidth that can be achieved because of the effect