Linearity Analysis of Source-Degenerated Differential Pairs for Wireline Applications

• Published in: IEEE open journal of circuits and systems Vol. 6; pp. 26 - 37
• Main Authors: Yadav, Kunal, Hsieh, Ping-Hsuan, Chan Carusone, Anthony
• Format: Journal Article
• Language: English
• Published: New York IEEE 2025; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Analog circuits; analog-to-digital converter (ADC); Broadband; Configuration management; Continuous time linear equalizer (CTLE); Degeneration; Gain; Harmonic distortion; Impact analysis; Integrated circuit modeling; Linearity; Mathematical models; Measurement; Nonlinearity; Performance evaluation; pulse amplitude modulation (PAM); Signal to noise ratio; Silicon-on-insulator; Symbols; Technology assessment; Transistors; Variable gain; wireline transceiver
• ISSN: 2644-1225; 2644-1225
• DOI: 10.1109/OJCAS.2024.3507543

This paper presents a comprehensive analysis of nonlinearities in differential pairs with source degeneration and their impact on wireline communication applications. We assess the suitability of three nonlinearity metrics to quantify the receiver analog front-end performance. This work identifies the primary sources of nonlinearity in differential pair circuits including, broadband Variable Gain Amplifiers (VGAs) and Continuous-Time Linear Equalizers (CTLEs) using circuit simulations. Furthermore, the linearity performance of different front-end configurations is evaluated, providing design insights. The analysis is validated through simulations with a 22-nm FDSOI technology.