Mohamed Hafed & Steven ChiangIntrospect Technology & Trust-Tek Corporation

PracticalExperiencesinMIPID-PHYSMandC-PHYSM ReceiverTesting

©2017MIPIAlliance,Inc.

InTheory…

2

DUTTestInstrument

©2017MIPIAlliance,Inc.

InRealLife…

3

IPBring-Up

• TestIPinisolation

• Theoreticalcase(perhaps!)

ComponentBring-Up

• Focusonentirechipfunctionalityincludinginterface

• Othereffectsstarttoappear

ApplicationModuleBring-Up

• Whereisthereceiver?

• Whereisthechannel?

• Whatstimulustouse?

TestRequirementsThroughProductLifecycleStages

©2017MIPIAlliance,Inc.

Agenda• Overviewofreceivertest• Illustrationofpracticalmoduleimplementationsand

evaluationplatforms• Recommendationsandbestpractices

4

©2017MIPIAlliance,Inc.

PhysicsofSignalTransmission

5

Transmitter

LargeSignalSmallNoise

Channel(cable,connector,flexPCB,package)

Receiver

SmallSignalLargeNoise

©2017MIPIAlliance,Inc.

ObjectiveofReceiverTest

6

Generateastressedsignalasifitwentthroughachannel

- ModelISI- ModelDCD- ModelJitter

Receiver

SmallSignalLargeNoise

©2017MIPIAlliance,Inc.

MIPID-PHYSM ReceiverSpecification

7

MIPID-PHYSMGenerator

DataRxClockRx

ReferenceChannel

ReferenceChannel

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MIPIC-PHYSM ReceiverSpecification

8

MIPIC-PHYSMGenerator DataRxReferenceChannel

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TheLinearChannelModel

9

Freq

|S21|

ΦS21

Freq

Freq

GrpDelayS21

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TheLinearChannelModel

10

LinearChannel

TimingEdgesLargelyUnaffectedinaLinearChannel

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TheLinearChannelModel

11

LinearChannel

TimingEdgesLargelyUnaffectedinaLinearChannel

Resultsinalmostnon-realisticjitterinjectionrequirements

©2017MIPIAlliance,Inc.

PracticalEvaluationBoard…Nonlinear!

12

IC

TestInstrument

FlexFlex

Discontinuity(Connector)

Discontinuity(Connector)BendorViaDiscontinuity

(TestPoint)

Discontinuity(Connector)

Discontinuity(Connector)

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LinearChannelVersusNon-LinearChannel

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TxEyeDiagram

LinearChannelEyeDiagram(~0.3UIClosure)

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LinearChannelVersusNon-LinearChannel

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TxEyeDiagram Non-LinearChannelEyeDiagram(~0.4UIClosure)Channelis25%Shorter

©2017MIPIAlliance,Inc.

PracticalExperiences:Skew

15

IC

TestInstrument

FlexFlex

BendorVia

©2017MIPIAlliance,Inc.

PracticalExperiences:Skew

16

PosNeg

PosNeg

CommonMode

Skewintroducescommon-modenoise(notgoodforreceiver!)Difficult todetectondifferentialscopeeyediagram

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PracticalExperiences:Reflections

17

IC

TestInstrument

FlexFlex

Discontinuity(Connector)

Discontinuity(Connector)

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PracticalExperiences:Reflections

18

Worst-caseexampleofachannelnon-linearity

Signalrisetimeissharp,butreflectionscancausebitflips

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PracticalExperiences:Reflections

19

StubCausingCompleteEyeClosure SlowingDataRateRevealsStubWaveform

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PracticalExperiences:Grounding

20

IC

TestInstrument

FlexFlex

Connector

Connector

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PracticalExperiences:Grounding

21

HSeyediagramaffectedbyCMandDiffeffectsLPwaveformsaffectedbycrossinglevelsandreflections

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PracticalExperiences:Inductance

22

IC

TestInstrument

FlexFlex

Discontinuity(TestPoint)

©2017MIPIAlliance,Inc.

PracticalExperiences:Inductance

23

Oftenduetotestpoints

Makescorrelationwithspecificationsdifficult

©2017MIPIAlliance,Inc.

Recommendations

24

Adoptasystem-levelapproachtotest ifyourevaluationboardlookslikeasystem

Identifystressparameterssuitableforcharacterizingyourdeviceinitsenvironment

Characterizereceiverperformanceacrosssystemconstraintsaswellasthroughideal“linear”channel