A Novel Self-Biased Phase-Locked Loop Scheme for WLAN Applications

Abstract

This article presents a novel self-biased phase-locked loop (PLL) scheme for wireless local area network (WLAN) applications. A novel self-biased circuit that contains a current mirror circuit and a variable resistor circuit related to the frequency division ratio are proposed. The proposed self-biased PLL scheme achieves a fixed damping factor. Moreover, the self-biased technology allows the PLL loop bandwidth to track the input reference frequency and division ratio. The proposed start-up circuit speeds up the locking of the PLL. In addition, the proposed differential-to-single-ended (DTS) converter can guarantee a 50% duty cycle without operating the PLL at twice the chip operating frequency. The proposed self-biased PLL is implemented in a Semiconductor Manufacturing International Corporation (SMIC) 55 nm CMOS process. The measured root-mean-square jitter (RMS-jitter) integrated of PLL is 2.4 ps with a dissipation of 8.6 mW, and the resulting figure-of-merit is −223.05 dBc/Hz.