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Research Article |

Analytical Method for Evaluating HD3 in CMOS LC Oscillators

Author(s): Nikorn Henngam1,Yutthachai Sillapawicharn2*,Buncha Sansoda3,Nikorn Saengngam4,Jirayuth Mahattanakul5

Published In : International Journal of Electrical and Electronics Research (IJEER)        Volume 14, Issue 2

Publisher : FOREX Publication

Published : 30 June 2026

e-ISSN : 2347-470X

Page(s) : 612-617

DOI: https://doi.org/10.37391/IJEER.140236

Abstract

This paper presents an analytical method for evaluating the third harmonic distortion (HD3) of the CMOS LC oscillator employing cross-coupled MOS differential pair. By assuming that the current generated by the cross-coupled differential pair and flowing through the LC tank is a square wave, a closed-form solution for HD3 is derived. To validate the theoretical analysis, simulations were performed, showing good agreement between the predicted and simulated results.

Keywords: Oscillator, Harmonic Distortion, Circuit Analysis, Nonlinear Distortion, Analog Integrated Circuits.




Nikorn Henngam, Assistant Professor, Faculty of Technical Education, Rajamangala University of Technology Thanyaburi, Thailand; Email: nikorn_h@rmutt.ac.th

Yutthachai Sillapawicharn, Associate Professor, Faculty of Technical Education, Rajamangala University of Technology Thanyaburi, Thailand; Email: yutthachai_s@rmutt.ac.th

Buncha Sansoda,Assistant Professor, Faculty of Technical Education, Rajamangala University of Technology, Thanyaburi, Thailand; Email: buncha_s@rmutt.ac.th

Nikorn Saengngam,Assistant Professor, Faculty of Technical Education, Rajamangala University of Technology Thanyaburi, Thailand; Email: nikorn@rmutt.ac.th

Jirayuth Mahattanakul,Professor, Faculty of Engineering and Technology, Mahanakhorn University of Technology, Thailand; Email: jirayut@mut.ac.th

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Nikorn Henngam, Yutthachai Sillapawicharn, Buncha Sansoda, Nikorn Saengngam, and Jirayuth Mahattanakul (2026), Analytical Method for Evaluating HD3 in CMOS LC Oscillators. IJEER 14(2), 612-617. DOI: 10.37391/IJEER.140236.