Designing High-Performance Phase-Locked Loops with High-Voltage VCOs

Phase-locked loops are used to provide the local-oscillator function in radio receivers and transmitters; for clock distribution and noise reduction, and as the clock source for high-sampling-rate analog-to-digital converters. This article considers the basics of PLLs, examines the current state-of-the-art in PLL design, discusses pros and cons of typical architectures, and introduces some alternatives to high-voltage VCOs.