A Fractional-N Synthesizable PLL Using DTC-Based Multistage Injection With Dithe

Abstract

A standard-cell-based fractional-N synthesizable phase-locked loop (PLL) [or multiplying-delay-locked loop (MDLL)] is proposed, where the multiple phases of the three- stage ring digitally controlled oscillator (DCO) are utilized for injection. The required digital-to-time converter (DTC) range is reduced to one third of the DCO’s period, resulting in higher linearity, less jitter, lower power consumption, and smaller area. The issue of the mismatches among DCO’s stages is solved by the proposed