A 7-GHz multiloop ring oscillator in 0.18-μm CMOS technology

Abstract

A novel delay stage for ring oscillator utilizing multiloop technique is presented in this paper. Different conventional delay stages for the multiloop ring oscillators have been reviewed and analyzed in this work. By using push-pull inverter as the secondary input in its delay cell, the proposed oscillator demonstrates a frequency improvement of up to 17% when compared with conventional designs. The fabricated oscillator is measured to cover a frequency range of 6.24-7.04 GHz. Operating in 1.8-V power supply, the oscillator manifests itself a phase noise of -107.7 dBc/Hz@10 MHz offset from a center frequency of 6.25 GHz. The proposed oscillator consumes a current of 40-51 mA from the 1.8-V supply and occupies an area of 440 lm 9 430 lm.

Design and Investigative Aspects of RF-Low Power 0.18-µm based CMOS Differential Ring Oscillator

“…Moreover, the transistor M1, M3 and M2, M4 are connected with the same gates of the delay cell. This type of configuration is called as push pull configuration, which is helpful to increase the gain [15]. By this configuration the higher frequency can be achieved easily.…”

“…This architecture is also commonly used for multiple output phases [10]. As LC counterpart, Ring oscillators occupy less chip area [3,11,15]. However, the single loop ring oscillators face some major frequency limitations such as number of stages and each inverter's smallest delay [15].…”

Design of a 3.2 mW Differential Ring VCO with Wide Tuning-Range using Self Biased Active Inductor Topology in 180 nm CMOS process

“…An LC resonant VCO can provide a superior phase-noise performance with drawbacks of large power dissipation, large layout area, and narrow tuning range [4]. A ring VCO on the other hand offers an easy integration, low power, wide tuning range and small layout area, but it suffers from poor phase-noise performance [5,6]. Ring VCOs can be designed in two configurations: single ended ring VCO and differential ended ring VCO.…”

Design and analysis of differential ring voltage controlled oscillator for wide tuning range and low power applications

“…Shunt‐Shunt feedback delay cell‐based DRO in Tu et al improves not only the tuning frequency range but also the output signal swing and power consumption. DRO implemented with delay cell with push‐pull inverters in Liu et al provides high frequency and introduces problems, such as the limited frequency tuning range, poor phase noise performance, and high power consumption. A delay cell with cross‐coupled symmetric load‐based DRO with wide frequency range, good linearity, and low power is proposed in Li and Lin .…”