A novel method for high-performance phase-locked loop

In this paper, we propose a phase-locked loop (PLL) with dual PFDs and a modified loop filter in which advantages of both PFDs can be combined and the trade-off between acquisition behavior and locked behavior can be achieved. By operating the appropriate PFD connected to the well-adjusted charge pump and regulating the loop bandwidth to input frequency ratio with an input divider and a modified loop filter, an unlimited error detection range, a high frequency operation, a reduced dead zone and a higher speed lock-up time can be achieved. The proposed PLL structure is designed using 1.5 μm CMOS technology with 5 V supply voltage.