An introduction to mixed signal ic test and measurement
PREFACE xvii
1.1 MIXED-SIGNAL CIRCUITS 1
1.1.1 Analog, Digital, or Mixed-Signal? 1
1.1.2 Common Types of Analog and Mixed-Signal Circuits
1.1.3 Applicationso f Mixed-SignaCl ircuits 3
1.2 WHY TEST MIXED-SIGNAL DEVICES? 5
1.2.1 The CMOS FabricationP rocess 5
1.2.2 Real-WorldCircuits 5
1.2.3 What Is a Test Engineer? 8
1.3 POST-SILICON PRODUCTION FLOW 10
1.3.1 Test and Packaging 10
1.3.2 Characterizatiovne rsusP roductionT esting 11
1.4 TEST AND DIAGNOSTIC EQUIPMENT 11
1.4.1 Automated Test Equipment 11
1.4.2 Wafer Probers 13
1.4.3 Handlers 13
1.4.4 E-Beam Probers 14
1.4.5 FocusedIo n BeamE quipment 15
1.4.6 Forced-TemperatuSrey stems 15
1.5 NEW PRODUCT DEVELOPMENT 16
1.5.1 ConcurrenEt ngineering 16
1.6 MIXED-SIGNAL TESTING CHALLENGES 17
1.6.1 Time to Market 18
1.6.2 Accuracy,R epeatabilitya, ndC orrelation 18
1.6.3 ElectromechanicaFli xturingC hallenges 18
1.6.4 Economicso f ProductionT esting 19
Chapter 2: The Test Specification Process
2.1 DEVICE DATA SHEETS 23
2.1.1 Purposeo f a DataS heet 23
2.1.2 Structure of a Data Sheet 24
2.1.3 Electrical Characteristics 27
2.2 GENERATING THE TEST PLAN 31
2.2.1 To Plan or Not to Plan 31
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vi Contents
2.2.2 Structure of a Test Plan 35
2.2.3 DesignS pecificationvse rsusP roductionT estS pecifications 36
2.2.4 Convertingt he DataS heetin to a Test Plan 37
2.3 COMPONENTS OF A TEST PROGRAM 38
2.3.1 Test Program Structure 38
2.3.2 Test Code and Digital Patterns 38
2.3.3 Binning 40
2.3.4 Test SequencCe ontrol 40
2.3.5 WaveformC alculationsa ndO therI nitializations 41
2.3.6 FocusedC alibrationsa ndD IB Checkers 41
2.3.7 CharacterizatioCn ode 42
2.3.8 Simulation Code 42
2.3.9 "Debuggability" 42
2.4 SUMMARY 43
Chapter 3: DC and Parametric Measurements
3.1 CONTINUITY 45
3.1.1 Purposeo f ContinuityT esting 45
3.1.2 Continuity Test Technique 46
3.1.3 Serial versus Parallel Continuity Testing 48
3.2 LEAKAGE CURRENTS 50
3.2.1 Purposeo f LeakageT esting 50
3.2.2 Leakage Test Technique 50
3.2.3 Serialv ersusP arallelL eakageT esting 51
3.3 POWER SUPPLY CURRENTS 51
3.3.1 hnportanceo f SupplyC urrentT ests 51
3.3.2 Test Techniques 51
3.4 DC REFERENCES AND REGULATORS 52
3.4.1 Voltage Regulators 52
3.4.2 Voltage References 55
3.4.3 Trirnmable References 55
3.5 IMPEDANCE MEASUREMENTS 56
3.5.1 Input hnpedance 56
3.5.2 Output hnpedance 58
3.5.3 Differential hnpedanceM easurements 59
3.6 DC OFFSET MEASUREMENTS 60
3.6.1 VMIDa ndA nalogG round 60
3.6.2 DC TransferC haracteristic(sG ain andO ffset) 60
3.6.3 OutputOffsetVoltage(Vo) 61
3.6.4 Single-EndedD, ifferential,a ndC ommon-ModeO ffsets 62
3.6.5 Input Offset Voltage (V os) 64
3.7 DC GAIN MEASUREMENTS 65
3.7.1 Closed-LoopG ain 65
3.7.2 Open-Loop Gain 68
3.8 DC POWER SUPPLY REJECTION RATIO 71
3.8.1 DC Power Supply Sensitivity 71
3.8.2 DC Power Supply Rejection Ratio 72
Contents vii
3.9 DC COMMON-MODE REJECTION RATIO 72
3.9.1 CMRRofOpAmps 72
3.9.2 CMRR of Differential Gain Stages 75
3.10 COMPARATOR DC TESTS 77
3.10.1 Input Offset Voltage 77
3.10.2 Thresho1dVoltage 78
3.10.3 Hysteresis 78
3.11 VOLTAGE SEARCH TECHNIQUES 79
3.11.1 Binary Searchevse rsusS tepS earches 79
3.11.2 Linear Searches 80
3.12 DC TESTS FOR DIGJTAL CIRCUITS 82
3.12.1 4H/4L 82
3.12.2 VldV/L 82
3.12.3 VaN/VoL 82
3.12.4 IoH/loL 82
3.12.5 IoSHa ndI osLS hortC ircuit Current 82
3.13 SUMMARY 83
Chapter 4: Measurement Accuracy
4.1 TERMINOLOGY 87
4.1.1 Accuracy and Precision 87
4.1.2 SystematicE rrors 88
4.1.3 Random Errors 88
4.1.4 Resolution( QuantizationE rror) 88
4.1.5 Repeatability 89
4.1.6 Stability 90
4.1.7 Correlation 91
4.1.8 Reproducibility 92
4.2 CALIBRATIONS AND CHECKERS 93
4.2.1 Traceability to Standards 93
4.2.2 Hardware Calibration 93
4.2.3 Software Calibration 93
4.2.4 SystemC alibrationsa ndC heckers 96
4.2.5 FocusedIn strumenCt alibrations 97
4.2.6 FocusedD IB Circuit Calibrations 101
4.2.7 DIB Checkers 102
4.2.8 Tester Specifications 103
4.3 DEALING WITH MEASUREMENT ERROR 106
4.3.1 Filtering 106
4.3.2 Averaging 111
4.3.3 Guardbanding 113
4.4 BASIC DATA ANALYSIS 114
4.4.1 Datalogs 114
4.4.2 Histograms 115
4.4.3 Noise, Test Time, and Yield 118
4.5 SUMMARY 120
viii Contents
Chapter 5: Tester Hardware
5.1 MIXED-SIGNAL TESTER OVERVIEW 123
5.1.1 General-PurposTee stersv ersusF ocusedB enchE quipment 123
5.1.2 Generic Tester Architecture 123
5.2 DC RESOURCES 125
5.2.1 General-PurposMeu 1timeters 125
5.2.2 General-PurposVeo ltage/CurrenSt ources 127
5.2.3 PrecisionV oltageR eferenceasn dU serS upplies 128
5.2.4 Calibration Source 128
5.2.5 Relay Matrices 128
5.2.6 Relay Control Lines 130
5.3 DIGITAL SUBSYSTEM 131
5.3.1 Digital Vectors 131
5.3.2 Digital Signals 131
5.3.3 Source Memory 132
5.3.4 Capture Memory 132
5.3.5 Pin Card Electronics 134
5.3.6 Timing andF ormattingE lectronics 136
5.4 AC SOURCE AND MEASUREMENT 139
5.4.1 AC ContinuousW aveS ourcea ndA C Meter 139
5.4.2 Arbitrary Waveform Generators 139
5.4.3 Waveform Digitizers 140
5.4.4 Clocking and Synchronization 141
5.5 TIME MEASUREMENT SYSTEM 141
5.5.1 Time Measurements 141
5.5.2 Time MeasuremenInt terconnects 142
5.6 COMPUTING HARDWARE 143
5.6.1 User Computer 143
5.6.2 Tester Computer 144
5.6.3 Array Processorasn dD istributedD igital SignalP rocessors 144
5.6.4 Network Connectivity 144
5.7 SUMMARY 144
Chapter 6: Sampling Theory
6.1 ANALOG MEASUREMENTS USING DSP 147
6.1.1 Traditionalv ersusD SP-BaseTd estingo f AC Parameters 147
6.2 SAMPLING AND RECONSTRUCTION 148
6.2.1 Use of Samplinga ndR econstructionin Mixed-SignaTl esting 148
6.2.2 Sampling:C ontinuous-Timaen dD iscrete-TimeR epresentation 149
6.2.3 Reconstruction 152
6.2.4 The Sampling Theorem and Aliasing 159
6.2.5 QuantizationE ffects 161
6.2.6 Sampling Jitter 166
6.3 REPETITIVE SAMPLE SETS 170
6.3.1 Finite and Infmite Sample Sets 170
6.3.2 CoherentS ignalsa ndN oncoherenSt ignals 171
Contents ix
6.3.3 Peak-to-RMSC ontroli n CoherenMt ultitones 173
6.3.4 Spectral Bin Selection 175
6.4 SYNCHRONIZATION OF SAMPLING SYSTEMS 179
6.4.1 SimultaneouTs estingo f Multiple SamplingS ystems 179
6.4.2 ATE Clock Sources 181
6.4.3 The Challengeo f Synchronization 183
6.S SUMMARY 184
Chapter 7: DSP-Based Testing
7.1 ADVANTAGES OF DSP-BASED TESnNG 189
7.1.1 ReducedTestTime 189
7.1.2 Separationo f SignalC omponents 189
7.1.3 Advanced Signal Manipulations 190
7.2 DIGITAL SIGNAL PROCESSING 190
7.2.1 DSP and Array Processing 190
7.2.2 Fourier Analysis of Periodic Signals 191
7.2.3 The TrigonometricF ourierS eries 192
7.2.4 The Discrete-TimeF ourierS eries 195
7.2.5 CompleteF requencyS pectrum 205
7.2.6 Time andF requencyD enormalization 210
7.2.7 Complex Form of the DTFS 211
7.3 DISCRETE-TIME TRANSFORMS 213
7.3.1 The Discrete Fourier Transform 213
7.3.2 The Fast Fourier Transform 216
7.3.3 Interpretingt he FFT Output 218
7.4 THE INVERSE FFT 230
7.4.1 Equivalenceo f Time- andF requency-DomaiInn formation 230
7.4.2 Parseval'sT heorem 232
7.4.3 Applications of the Inverse FFT 233
7.4.4 Frequency-DomaiFni ltering 234
7.4.5 Noise Weighting 239
7.5 SUMMARY 240
APPENDIXA.7.1 241
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Chapter 8: Analog Channel Testing
8.1 OVERVIEW 249
8.1.1 Types of Analog Channels 249
8.1.2 Typeso f AC ParametricT ests 250
8.1.3 Review of Logarithmic Operations 250
8.2 GAIN AND LEVEL TESTS 251
8.2.1 Absolute Voltage Levels 251
8.2.2 Absolute Gain and Gain Error 256
8.2.3 Gain Tracking Error 258
8.2.4 PGA Gain Tests 260
8.2.5 FrequencyR esponse 265
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8.3 PHASE TESTS 273
8.3.1 PhaseR esponse 273
8.3.2 Group Delay and Group Delay Distortion 278
8.4 DISTORTION TESTS 280
8.4.1 Signal to Hannonic Distortion 280
8.4.2 InteTnlodulatioDn istortion 283
8.5 SIGNAL REJECTION TESTS 284
8.5.1 Common-ModeR ejectionR atio 284
8.5.2 Power Supply Rejection and Power Supply Rejection Ratio 287
8.5.3 Channel-to-ChannCelr osstalk 289
8.5.4 Clock and Data Feedthrough 293
8.6 NOISE TESTS 293
8.6.1 Noise 293
8.6.2 Idle ChanneNl oise 294
8.6.3 Signal to Noise, Signal to Noise and Distortion 296
8.6.4 SpuriousF reeD ynamicR ange 298
8.6.5 Weighting Filters 300
8.7 SIMULA nON OF ANALOG CHANNEL TESTS 304
8.7.1 MATLAB Model of an Analog Channel 304
8.8 SUMMARY 308
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