A. Nikas, Sreenivas Jambunathan, Leonhard Klein, M. Völker, M. Ortmanns
{"title":"A Low Distortion Continuous Time Sigma Delta Modulator using a High Input Impedance Instrumentation Amplifier for Neural Recording","authors":"A. Nikas, Sreenivas Jambunathan, Leonhard Klein, M. Völker, M. Ortmanns","doi":"10.1109/BIOCAS.2018.8584687","DOIUrl":null,"url":null,"abstract":"In this paper an architecture for a continuous time sigma delta modulator used in a neural recording channel is proposed. The instrumentation amplifier based input structure of the converter exhibits a high input impedance and linear behavior. Properties making its use interesting in analog frontends for direct application on sensor elements. Circuit linearity is achieved solely by negative feedback. A prototype was developed as a 2nd order single bit modulator in a cascade of integrators feedforward form and was taped-out in a 180nm technology. Simulations show an input impedance of >1GΩ and a THD of 0.012%. The input referred noise is 2.2µV at an average current consumption of 14µA occupying an area of 0.07mm2.","PeriodicalId":259162,"journal":{"name":"2018 IEEE Biomedical Circuits and Systems Conference (BioCAS)","volume":"57 1","pages":"0"},"PeriodicalIF":0.0000,"publicationDate":"2018-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"2","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"2018 IEEE Biomedical Circuits and Systems Conference (BioCAS)","FirstCategoryId":"1085","ListUrlMain":"https://doi.org/10.1109/BIOCAS.2018.8584687","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"","JCRName":"","Score":null,"Total":0}
引用次数: 2
Abstract
In this paper an architecture for a continuous time sigma delta modulator used in a neural recording channel is proposed. The instrumentation amplifier based input structure of the converter exhibits a high input impedance and linear behavior. Properties making its use interesting in analog frontends for direct application on sensor elements. Circuit linearity is achieved solely by negative feedback. A prototype was developed as a 2nd order single bit modulator in a cascade of integrators feedforward form and was taped-out in a 180nm technology. Simulations show an input impedance of >1GΩ and a THD of 0.012%. The input referred noise is 2.2µV at an average current consumption of 14µA occupying an area of 0.07mm2.