A g m /I D Methodology Based Data-Driven Search Algorithm For the Design of Multi-Stage Multi-Path Feed-Forward-Compensated Amplifiers Targeting High Speed Continuous-Time Σ∆-Modulators

This work presents a methodology for sizing transistors of a multi-stage, multi-path capacitor-less feed-forward compensated operational amplifiers employed in advanced CMOS process implementation of continuous-time bandpass Σ∆-modulators. The paper describes the methodology: on system level, dealin...

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Bibliographic Details
Published in:IEEE transactions on computer-aided design of integrated circuits and systems p. 1
Main Authors: Gebreyohannes, Fikre Tsigabu, Porte, Jacky, Louërat, Marie-Minerve, Aboushady, Hassan
Format: Journal Article
Language:English
Published: IEEE 17.01.2020
Subjects:
Computer Science
multi-path
feed-forward compensation
multi-stage
search algorithm
continuous time
sigma delta modulator
g m /i D methodology
operational amplifier
Matlab script
ISSN:0278-0070
Online Access:Get full text
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Summary:This work presents a methodology for sizing transistors of a multi-stage, multi-path capacitor-less feed-forward compensated operational amplifiers employed in advanced CMOS process implementation of continuous-time bandpass Σ∆-modulators. The paper describes the methodology: on system level, dealing with the placement of poles and zeros; and on circuit level, discussing issues related to biasing, frequency response and other important performance metrics of the basic diff-pair. Algorithms are provided to simplify mathematical aspects of the work. The validity and the limitations of the proposed methodology are further discussed from the single-pole system used to model the individual amplification stages of the multi-stage amplifier. The worthiness of the proposed methodology in sizing the transistors of complex amplifier structures such as the capacitor-less multi-stage, multi-path feed-forward-compensated amplifiers is demonstrated using two design examples. A 3 rd-order amplifier with a DC gain of 52.6 dB and that reaches a unity-gain frequency of above 14 GHz while consuming only 5.6 mA from a 1 V supply; and a 4 th-order amplifier with DC gain of 73.5 dB that achieves a 25.7 dB gain at 1 GHz while consuming 4.8 mW are designed in 28nm CMOS FDSOI.
ISSN:0278-0070
DOI:10.1109/TCAD.2020.2966998