Design of High Frequency, Low Phase Noise LC Digitally Controlled Oscillator for 5G Intelligent Transport Systems

Abstract

This paper presents the design, simulation, and measurements of a low power, low phase noise 10.25–11.78 GHz LC digitally controlled oscillator (LC DCO) with extended true single phase clock (E-TSPC) frequency divider in 130 nm complementary metal–oxide–semiconductor (CMOS) technology for 5G intelligent transport systems. The main goal of this work was to design the LC DCO using a mature and low-cost 130 nm CMOS technology. The designed integrated circuit (IC) consisted of two parts: the LC DCO frequency generation and division circuit and an independent frequency divider testing circuit. The proposed LC DCO consisted of the following main blocks: the high Q-factor inductor, switched-capacitors block, cross-coupled transistors, and the current control block. Inductors with switched-capacitors block formed an LC tank. The designed E-TSPC frequency divider consisted of eight blocks connected in a series; each block increased the division ratio by a factor of two. The frequency of the input signal was divided in the region from two to 256 times using the designed divider. The main parameters of the designed E-TSPC divider and the LC DCO measurements were given as follows: LC DCO achieved a wide tuning range from 10.25 GHz to 11.78 GHz (1.53 GHz, 15.28% bandwidth); phase noise at 1 MHz offset frequency from LC DCO lowest carrier frequency was −113.42 dBc/Hz; phase noise at 1 MHz offset frequency from LC DCO highest carrier frequency was −110.51 dBc/Hz; The average power consumption of the designed LC DCO core and E-TSPC divider were 10.02 mW and 97.52 mW, respectively; the figure of merit (FOM) and the extended FOMT values of the proposed LC DCO were −183.52 dBc/Hz and −187.20 dBc/Hz, respectively. These FOM and FOMT results were achieved due to very low phase noise (−113.52 dBc/Hz) and a wide frequency tuning range (15.28%). The total layout area including the pads was 1.5 mm × 1.5 mm, with the largest part of the layout occupied by the proposed LC DCO (193 µm × 311 µm). The largest part of the LC DCO was occupied by the inductor 184 µm × 184 µm. The manufactured chip was packed into a quad flat no-leads (QFN) 20 pads package.