Analysis of Phase Noise in 28 nm CMOS LC Oscillator Differential Topologies: Armstrong, Colpitts, Hartley and Common-Source Cross-Coupled Pair

Ilias Chlis,Domenico Pepe,Domenico Zito

doi:10.1142/s0218126615500528

Ilias Chlis, Domenico Pepe + Show 1 more

Open Access

https://doi.org/10.1142/s0218126615500528

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Abstract

Comparative Phase Noise analyses of common-source cross-coupled pair, Colpitts, Hartley and Armstrong differential oscillator circuit topologies, designed in 28 nm bulk CMOS technology in a set of common conditions for operating frequencies in the range from 1 GHz to 100 GHz, are carried out in order to identify their relative performance. The impulse sensitivity function (ISF) is used to carry out qualitative and quantitative analyses of the noise contributions exhibited by each circuit component in each topology, allowing an understanding of their impact on phase noise. The comparative analyses show the existence of five distinct frequency regions in which the four topologies rank unevenly in terms of best phase noise performance. Moreover, the results obtained from the ISF show the impact of flicker noise contribution as the major effect leading to phase noise degradation in nanoscale CMOS LC oscillators.

Highlights

Advances in wireless communications have a great impact on our societal and economic challenges.[1,2,3,4,5] One of the most critical circuits of modern radiofrequency transceivers is the local oscillator, i.e., an autonomous circuit operating as the \pulsing heart" of such systems, in an analogy with the human body
Driven by the above motivations, in this paper we report a comparative investigation of phase noise (PN) in the common-source cross-coupled pair, Colpitts, Hartley and Armstrong di®erential oscillator topologies, with the main objective of bringing to the light the contributions of the inherent noise sources in the most widespread oscillator topologies reported in the literature
All the topologies were investigated under the same common design conditions, such as power consumption, supply voltage, transistor current density and sizing, inductance and quality factor of the integrated spiral inductors, coupling factor of the integrated transformers, and considering the full models of the transistors available within the process design kit, including all their parasitic components related to their actual size

Summary

Introduction

Advances in wireless communications have a great impact on our societal and economic challenges.[1,2,3,4,5] One of the most critical circuits of modern radiofrequency transceivers is the local oscillator, i.e., an autonomous circuit operating as the \pulsing heart" of such systems, in an analogy with the human body. The Hartley topology exhibited the best performance at higher frequency.[10] Despite these results provide arst interesting perspective, this is limited by the comparison between a di®erential topology, i.e., cross-coupled common-source differential pair, and two single-ended topologies, Colpitts and Hartley. Driven by the above motivations, in this paper we report a comparative investigation of PN in the common-source cross-coupled pair, Colpitts, Hartley and Armstrong di®erential oscillator topologies, with the main objective of bringing to the light the contributions of the inherent noise sources in the most widespread oscillator topologies reported in the literature.

Circuit Topologies

Comparison of Phase Noise Performance

Contributions of the Device Noise to Phase Noise

Findings

Conclusions