Susceptibility ofaSigma-Delta Converter toEMI

Thispaperdiscusses thesusceptibility ofSigma- Fs DeltaAnalog-to-Digital converters todisturbances, arising from x(t) y(n) environmental electromagnetic pollution orfromtheparasitic coupling withnoisybuilding blocksintegrated inthesame yt) system-on-chip (SoC) orsystem-in-package (SiP). 1bit Theoperation ofafirst-order switched-capacitor sigma-delta DAC converter, whichreceives atitsinput nominal signals corrupted byradio-frequency interference isanalyzed through timedomain Fig. IBlock diagram ofaFirst Order Sigma-Delta converter. computersimulations and therootcausesoffailures are Thepaperhasthefollowing structure: Section IIdescribes discussed indetail. thearchitecture andtheoperation ofafirst order LAconverter, I.INTRODUCTION whichisbasedontheswitched capacitor technique, while Section IIIsummarizes theresults oftimedomaincomputer In thelastdecades, theeffect of electromagnetic simulations, andbasedonthat, asimplified modeldescribing interference (EMI)onteatoofintegrated circuits has theRFIdistortion inMOS switches ispresented. Finally, beenextensively observed andinvestigated, whichinturn has sections IVdrawssomeconcluding remarks. ledtonewdesign guidelines andnewcircuit topologies which makeSoCsless susceptible toEMI.Tothis purpose, previous II.FIRST ORDERSIGMADELTACONVERTER workshaveexplained thereasonofEMI demodulation in Commonfirst orderLAconverters looklikethatshownin basic circuits suchassingle stageamplifiers, opamps(1-2) Fig.2. Theiroperation canbe described asfollows: the andbandgap voltage reference (3). Moreover, theeffects of difference (delta) between theinput andthefeedback signals RFIontheoperation ofelementary switched-capacitor