EMC of Analog Integrated Circuits

249 Pages·2010·4.59 MB·English

by  Jean-Michel Redouté

EMC of Analog Integrated Circuits
ANALOGCIRCUITSANDSIGNALPROCESSINGSERIES
ConsultingEditor:MohammedIsmail.OhioStateUniversity
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Jean-Michel Redouté (cid:2) Michiel Steyaert
EMC of Analog Integrated
Circuits
Jean-MichelRedouté MichielSteyaert
Dept.ElectricalEngineering(ESAT) Dept.ElectricalEngineering(ESAT)
KatholiekeUniversiteitLeuven KatholiekeUniversiteitLeuven
KasteelparkArenberg10 KasteelparkArenberg10
3001Leuven,Belgium 3001Leuven,Belgium
[email protected] [email protected]
SeriesEditor:
MohammedIsmail
205DreeseLaboratory
DepartmentofElectricalEngineering
TheOhioStateUniversity
2015NeilAvenue
Columbus,OH43210,USA
ISBN978-90-481-3229-4 e-ISBN978-90-481-3230-0
DOI10.1007/978-90-481-3230-0
SpringerDordrechtHeidelbergLondonNewYork
LibraryofCongressControlNumber:2009937640
(cid:2)cSpringerScience+BusinessMediaB.V.2010
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Preface
Environmentalelectromagneticpollutionhasdrasticallyincreasedoverthelast
decades. The omnipresence of (wireless) communication systems, new and
various electronic appliances and the use of ever increasing frequencies, all
contributetoanoisyelectromagneticenvironmentwhichactsdetrimentallyon
sensitive electronic equipment. Integrated circuits constitute the beating heart
ofalmostanygivenelectronicsystemnowadays:luckily,owingtotheirsmall
sizes,theyarenoteasilydisturbedbyradiateddisturbances,becausetheirtiny
on-chipinterconnectionsaremuchtoosmalltofunctionaseffectiveantennas.
However, the ultimate contribution comes from the conducted interferences
whicharepresentonthenoisyandrelativelylongprintedcircuitboardtracks,
usedtoconnectandinterconnecttheintegratedcircuitsinquestion.
Asidefromapollutedelectromagneticspectrum,integratedcircuitsmustbe
able to operate satisfactorily while cohabiting harmoniously in the same ap-
pliance,andnotgenerateintolerablelevelsofelectromagneticemission,while
maintaining a sound immunity to potential electromagnetic disturbances. As
different electronic systems are compactly integrated in the same apparatus,
theparasiticelectromagneticcouplingbetweenthesecircuitssharingthesame
signal,powerandgroundlines,isacriticaldesignparameterthatcannolonger
be safely excluded from a product design flow. This dense integration level
links the electromagnetic compatibility (EMC) issue of integrated circuits to
the graceful coexistence between systems: as an example, Bluetooth, GSM
andWiFiserviceshavetocoexistandoperateinharmonywithinthecrammed
confinementofamodernmobilephone.
Distinct frequency allocations provide a shield against electromagnetic in-
terferences by separating the signal spectra of different systems from each
other: nevertheless, the intrinsic nonlinearity of active devices may cause the
demodulationofinterferingoutofbandsignals,wherebyspurioussignalstend
to appear in the frequency band of the exposed circuit. Furthermore, these
outofbanddisturbances mayinduce aseveredistortion ofthe wantedsignals
vi Preface
(which is certainly not recommended),and DC shifterrorson sensitive nodes
in the respective circuit, hereby possibly driving the latter out of its correct
operationmode(whichisevenlessacceptable).Analogcircuitsareinpractice
moreeasilydisturbedthantheirdigitalcounterparts,sincetheydon’thavethe
benefit of dealing with predefined levels which ensure an innate immunity to
disturbances.
The objective of the research domain presented in this book is to improve
theelectromagneticimmunityofconsideredanalogintegratedcircuits,sothat
theystarttofailatrelevantlyhigherconductionlevelsthanbefore.
J.-M.RedoutéandM.Steyaert
Contents
1. INTRODUCTION 1
1 Thepioneersofwirelesscommunication 1
2 Evolutionofawarenessofelectromagneticcompatibility 3
3 Electromagneticcompatibilityofintegratedcircuits 5
4 Scopeofthisbook 7
2. BASICEMCCONCEPTSATICLEVEL 11
1 Introduction 11
2 DefinitionofEMC,EMI,EMSandEME 12
3 Sourcesofelectromagneticinterference 14
4 Electromagnetismversusintegratedcircuitdesign 15
4.1 Electricallength 15
4.2 Nearfieldversusfarfield 17
4.3 Radiationofaconductor 19
4.4 BasicEMCantennaconcepts 20
4.5 Radiated,inducedandconducteddisturbances 22
4.6 Practicalexample 24
5 Intra-chipversusexternally-coupledEMC 27
6 Analogversusdigitalintegratedcircuits 29
7 EMCinautomotiveapplications 31
8 ImmunitymeasurementmethodsforIC’s:IEC62132 31
viii Contents
3. EMCOFINTEGRATEDCIRCUITSVERSUSDISTORTION 37
1 Introduction 37
2 RelationshipbetweenEMIresistingdesignanddistortion 39
2.1 Lineardistortion 39
2.2 Nonlineardistortion(rectification) 40
2.3 Weakandstrongnonlineardistortion 43
3 Casestudy1:diodeconnectedNMOStransistor 45
4 Casestudy2:NMOSsourcefollower 50
5 Casestudy3:NMOScurrentmirror 52
5.1 Capacitordecouplingthemirrornode 57
5.2 Low-passR-C filterinthemirrornode 58
5.3 Low-passR-C filterinthedrainofM 60
1
5.4 EMIresisting(4-transistor)currentmirror 61
5.5 EMIresisting(Wilsontotempole)currentmirror 67
5.6 ComparisonofEMIsusceptibilityofcurrentmirrors 69
6 Casestudy4:EMIsusceptibilityinESDprotections 72
6.1 WeaknonlineardistortioninESDprotections 73
6.2 StrongnonlineardistortioninESDprotections 78
6.3 ESDprotections:generalconclusions 80
7 EMIinducedDCshift 81
4. EMIRESISTINGANALOGOUTPUTCIRCUITS 83
1 Introduction 83
2 Categorizationofanalogoutputstructures 85
2.1 Common-drainoutputcircuits 85
2.2 Common-sourceoutputcircuits 88
2.3 Comparingtheelectromagneticsusceptibility 89
2.4 LargeEMIamplitudes 93
3 Casestudy1:EMIresistingDCcurrentregulator 95
3.1 EMIissuesinaclassicDCcurrentregulator 95
3.1.1 EMIissues:smallsignalanalysis 97
3.1.2 EMIissues:largesignalanalysis 99
3.1.3 DecouplingcapacitorC 100
d
3.2 DCcurrentregulatorwithahighimmunitytoEMI 102
3.3 Measurements 106
Contents ix
4 Casestudy2:EMIresistingLINdriver 107
4.1 ClassicLINdriver 111
4.1.1 Linearoperationmode 114
4.1.2 Nonlinearoperationmode 116
4.2 EMIresistingLINdrivertopology:LINdriver1 117
4.2.1 EMIpath1 118
4.2.2 EMIpath2 122
4.2.3 Slopecontrolfunction 129
4.2.4 Measurements 129
4.3 EMIresistingLINdrivertopology:LINdriver2 133
4.3.1 Smart-powermode 133
4.3.2 Slopepumpingreduction 136
4.3.3 Measurements 138
5. EMIRESISTINGANALOGINPUTCIRCUITS 141
1 Introduction 141
2 Casestudy1:electromagneticimmunityofCMOSoperational
amplifiers 142
2.1 Asymmetricslewrate 145
2.2 Strongnonlinearbehavioroftheinputdifferentialpair 148
2.3 Weaknonlinearbehavioroftheinputdifferentialpair 149
2.3.1 EMIinducedoffsetinaclassicdifferentialpair 149
2.3.2 Classicdifferentialpairusingsourcedegeneration 154
2.3.3 Cross-coupleddifferentialpair 155
2.3.4 Differentialpairwithlow-passR-C filter 158
2.3.5 Improvedcross-coupleddifferentialpair 160
2.3.6 Source-buffereddifferentialpair 161
2.3.7 Comparison 169
2.4 EMIinducedoffsetmeasurementsetups 169
2.5 Measurements 177
3 Case study 2: EMI resisting instrumentation amplifier input
circuit 182
3.1 Classicinstrumentationamplifierinputcircuit 183
3.2 Inputcircuitusingcurrentsourcesmodulation 189
3.3 Simulations 193