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ADI 高速、混合、微弱信号布线指南.pdfCaveriersEdgar ls Sent to the Driver AgainEdgar travels at 6 inches per nanosecondDriverReceiverTransmissionLineADIConfidentialDEVICE38
LarerierEdgar ls Sent to the Receiver a 'Third TimeEdgar travels at 6 inches per nanosecondDriverReceiverTransmission LineADIConfidentialDEVICE39
everage Ohms' law to minimize the impedance mismatch a
ManagingtheLoadE
GB/T 4630-2011 辽宁绒山羊Eachmethodhasitsprosandcons.
MENSSDarererHighSpeed PCB Designand'LayoutParallel TerminationParallel resistoratthe receivercanworkwell buthas:.Increases drive current and thus increases power dissipation.IncreasedCrosstalk,IncreasedEMl.Increased ground bounce or supply noise (depending on if theparallel resistor is pulled high or low).DriverDrive currentReceiverabout 50 mATransmission LineDEVICEADIConfidential42
MENSSDarerentHigh Speed PCB Design and 'LayoutSeries TerminationSeries resistoratthe driverisless disruptive:...but the driver impedance is nonlinear and you lose someenergy getting into the transmission lineDriverReceiverTransmission LineADIConfidentialDEVICE43
CaverfersDDR SDRAM TerminationDDRusesDualterminationAtVCC/2=1.25V,loofthedriverisabout14mADriverReceiverVCC/2Transmission LineADIConfidentialDEVICE
MESSCarererEdaarMeets DDR in the'Real WorldThe Series Resistor Plus the Drive impedance is 50 OhmsTheParallelResistoris50OhmsThe Transmission Line Impedance is 60 Ohms (Bad PCB)DriverReceiverVCC/22550WTransmission LineADIConfidentialDEVIC45
TheReceiverisa5oOhmLoadButtheTransmissionLinewas 6o Ohms Due To FR4 Construction and Fabrication Errors TheReflectedEnergyis:
TheReceiverisa5oOhmLoadButtheTransmissionLinewas
CaverfersEdgaris Reflected+Edgartravels at 6 inches per nanosecondDriverReceiverVCC/2TransmissionLineADIConfidentialDEVICE47
TheDriverisa5oOhmLoadButtheTransmissionLinewas60 OhmsDueToFR4ConstructionandFabricationErrors TheReflectedEnergyis:
TheDriverisa50OhmLoadButtheTransmissionLinewas60
CarerfersEdgaris ReflectedEdgarTravelsat6inchespernanosecond Edgar is now about 1/100 of its original EnergyTherefore Edgar changes the voltage by 1/10 or about 0.2 voltsDriverReceiverVCC/2AWTransmission LineADIConfidentialDEVIC
MESSarererGetting the best performance on our PCBsAsamplifiersandconverters'performanceimprovedachievetheirperformanceonyourPCBwill bechallenging.Layoutguide&designnotestrainingbeforePCBlayoutwill save muchtime in debuggingMovingontoday'strainingMixedSignalPcBLayoutTechniguesSmallSignalPCBLayoutTechniguesStaniar 1.8ADIConfidential
The World Leader in High Performance Signal Processing SolutionsMixed Signal PcBLayoutGrounding DataAcguisitionSystemADIANALOGDEVICES
Digital Currents Flowing in AnalogReturn Path Create Error VoltagesCircuSensitiveAnalogSensitive AnalogClockCircuitryDisruptedbyCircuitrysafefromCircuitryDigital SupplyNoiseDigitalSupplyNoiseIpAANALOGDIGITALANALOGDIGITALCIRCUITSCIRCUITS.CIRCUITSCIRCUITSCGNDGND'A + lp'DREFREFIncorrectADIConfidentialCorrectDEVIC55
yacecMESSLarerienGrounding Mixed Signal'iCs with LowInternal Digital Currents: Multiple PC BoardsVN=NOISE BETWEENY.NGROUNDPLANESVDFILTERVAVpRBUSANALOGMIXEDBUFFERSIGNALDIGITALCIRCUITSDEVICELATCHCIRCUITSAGNDDGNDANALOGDIGITALGROUNDPLANEGROUNDPLANEADTOSYSTEMTOSYSTEMANALOGSUPPLYDIGITALSUPPLYDEVICEANAAOSYSEEMSTARGROUND56
CaarerensStar Ground Systemlwhich has Separated AnalogandDigitalGroundPlanesANALOGPCBPCBVDIGITALANALOGDIGITALGROUNDGROUNDGROUNDGROUNDPLANEPLANEPLANEPLANENoDIGITALGROUNDPLANENoconnectionconnectionBACKPLANENotOverLayANALOGGROUNDPLANHighVoltageCapacitormayneedSYSTEMPOWERheretoprovidehighfrequencySTARSUPPLIESinterferenceshotcutpath(forEMC/EMIpurpose)GROUND[// /DEVIC
The World Leader in High Performance Signal Processing SolutionsMixed Signal PCBLayoutUsing Ground PlaneADIANALOGDEVICES
The World Leader in High Performance Signal Processing SolutionsMixed Signal PcBLayoutPower Filter&DecouplingCapacitorconsiderationANALOGDEVICES
LarerenGrounding and Decoupling PointsVFERRITEBEAD25SEETEXTAVAVDDORADCBUFFERAMPORGATEDACORREGISTERTO OTHERDIGITALCIRCUITSAGNDDGNDVOLTAGESAMPLINGREFERENCECLOCKANALOGGROUNDPLANEGENERATORDIGITALAADGROUNDPLANEADIConfidential68
MESSarererDecoupling on SOic'partsCORRECTINCORRECTOPTIONALFERRITEBEADSPOWERDECOUPLINGPOWERDECOUPLINGSUPPLYCAPACITORSUPPLYCAPACITORTRACETRACEV+V+ICPCBICTRACEGNDGNDVIAS TOGROUNDPLANEVIA TOGROUNDPLANERULEOFTHUMB:VIARESISTANCE~1mQ2,VIAINDUCTANCE~1nHLocalizedhighfreguencysupplyfiltersprovideoptimumfilteringanddecouplingviashortlowinductancepath(groundplane)Rule of Thumb:Viaresistance~1m2,Via inductance~1nHDEVICEADIConfidential69
LarerienDecouplingonLQFFVCCCCorrectGNDVCCLQFPViaLFCSPVCCWrongGNDGNDGNDGNDVCCWrongGNDCorrectNolongtraceunderIWrongShorttracethentobottombyviaMaybe your AD9779 Layout like this!ShorttracetoGNDorPowerunderICShorttracetodecoupleCapacitorsDEVICADfConfidential
MESCarerferDifferent Capacitors'Impedance vs.Frequency1,000,000MuRata0805GMR216SERIES100,0001000pF10,0002.2uF0.01uF0.1uF1,0000.01uF0.1uF100pf1001000pF2.2uF100pf1010.10.010.0010.0010.010.11101001.00010.000Frequency [MHz]Paralleling caps reduces impedance over a wider frequency range.Putthe smallerdecoupling capcitoras near aspossible topowerpin.DEVICEADIConfidential
The World Leader in High Performance Signal Processing SolutionsMixed Signal PCBLayoutParasiticConsiderationADIANALOGDEVICES
ApproximateTraceInductanceAlldimensionsareinmm2LW+H) + 0.5H1cmof0.25mmPCtrackhasaninductanceof9.59nH(H= 0.038mm,W= 0.25mm,L= 1cm)ExampleMinimize Inductance1)UseGroundplaneL=2.54cm=25.4mm,W=0.25mm2) Keep length short: Halving theH= .035mm (1oz copper)lengthreduces inductance byStrip Inductance = 28.8nH44%3) Doubling width only reducesAt 10MHz Z, = 1.86 2 a 3.6% error in a 502systeminductanceby11%ADIConfidential
MESSDarerersBASICPRINCIPLES OE COUPLINGINTERFERENCECIRCUITSIGNALCIRCUITA = AREANOISESOURCEINDUCED(f.)VOLTAGEINTERFERENCESIGNALCAPACITIVECOUPLINGLOOPLOOPEQUIVALENTCIRCUITMODELcM=MUTUALINDUCTANCEB=MAGNETICFLUXDENSITYA=AREAOFSIGNALLOOPON=2元fN=FREQUENCYOFNOISESOURCE V21VcOUPLEDV = INDUCED VOLTAGE = ONMIN = OABZ, = CIRCUIT IMPEDANCEBASICPRINCIPLESOEINDUCTIVECOUPLINGZ2 = 1/jCVCOUPLED= VNZ1 + Z2DEVICADIConfidential
Parasitic ModelCapacitorParasiticModeResistorParasiticModelR,RsCpRDACDAC=CapacitorRp=insulation resistanceRs=equivalentseriesresistance(ESR)RL=seriesinductanceoftheleadsandplatesR=ResistorRpA=dielectric absorptionCp=ParallelcapacitanceCpA = dielectric absorptionL=equivalentseriesinductance(EsL)ADIConfidential
CarerensStray Capacitance SimulationAD8065an/Ar6.5% overshootR31R212.7850WR11PulseResponsewith1pFStrayCapacitance1pFstraycapacitanceReduceOvershoot1.8dB peaking1)Increaseboardthickness2)Reducetrace/padarea3)Removegroundplane4)LowerResistance128(m1828312123aHz182HzFreguencyResponsewith1pStrayCapacitanceDEVICEADIConfidential83
PocecenCaverersStray Inductance Simulation Schematic1"x0.01"=29nHU11/1129nHoUAD8055an/ADR31R21V211k1kV31AD8055R11PulseResponseWithandWithoutGroundPlane150Approximately 0.6dB over shoot.1.88.57U238. ons248.8nsU(R2:1)258.0nsDEVICADIConfidential84
CarerersPowerSupplyBypassingElectrolyticCeramicBypassB1ADXXXXADXXXXIncorrectCorrectADIConfidential86
CarerieSOlClLayout ExampleRDisableRGVINoutRcElectrolyticCeramicBypassBypassCompCap
The World Leader in High Performance Signal Processing SolutionsMixed Signal PCBLayoutControl DifferentiaLine ImpedanceADIANALOGDEVICES
MESCoarerenMeasuring the TMDs pair impedanceTDR(TimeDomainReflector)incidentD.U.T50 0hmTDRReflectionsStepGeneratorWaveformDigitizerHigh SpeedS/HADIConfidential
MESThe Visual Tumped interconnect analysisusing TDRShunt Cdiscontinuity9N1NSeriesontinuity1QN.11N.ity013DEVICIADIConfidential94
DL/T 5489-2014 火力发电厂循环水泵房进水流道设计规范MESCoarerenSummary'Mixed Signal Layout TechniguesUse ground plane.Highspeedapplicationsrequirelowimpedancereturns·HelpsminimizeparasiticsParasiticsParasitic capacitance,inductanceandresistancecanruinthebestdesignedcircuit.Layoutiscritical!Shielding Long WireControl Differential LineImpendenceADIConfidentialDEVIC95
The World Leader in High Performance Signal Processing SolutionsSmall Signal PcBLayoutConsider loss onTrack ResistorANALOGDEVICES
The World Leader in High Performance Signal Processing SolutionsSmall Signal PCBLayoutProper GroundingShielding CableANALOGDEVICES
MESCareriersGroundloopsin shieldtwisted pair cableBRIDGEA2ANDACONDITIONINGCIRCUITSNC/777GND 1GND 2BRIDGEANDRTDCONDITIONINGCIRCUITSGroundloopsinshieldtwistedpair"HYBRID"cable can cause errorsGROUNDVCauses Current inShield (Usually50/60Hz)DifferentialErrorVoltageisProducedatInputof A2Unless:Hybrid qrounding of shieldedA1Output isPerfectlyBalancedandcablewithpassivesensorA2InputisPerfectlyBalancedandCableisPerfectly BalancedADIConfidential
The World Leader in High Performance Signal Processing SolutionsSmall Signal PCBLayoutMinimizePCBLeakage by GuardRingANALOGDEVICES
The World Leader in High Performance Signal Processing SolutionsSmall Signal PCBLayoutMinimize PCB HeatingTemperature SensorsANALOGDEVICES
HJ 764-2015 砷水质自动在线监测仪技术要求及检测方法MESSLarerienMinimize PCB Heating Temperature SensorsCorrectPCBlayoutformeasuringambienttemperature•Many designers don'twanttomeasuretheMainHeat SourceTempPCBtemperatureJustwantto measuretheambientair(uController)Sensortemperature·Problem is,howdo you preventtheheatfromAD7414/15EBthePcBheatsourcesaffectingtheambienttemperaturemeasurementofthetempsensorTips for ambient temperature measurementUseahatchedGNDplane.ReduceGNDplaneareatherefore increasingthermal resistanceKeepthetempsensorasfarawayfromheatsourcesaspossible.UseaseparateGNDplaneforthetempsensorandkeepconnectionstomainGNDplaneaslowaspossible.UsenarrowGNDconnectionsasthiswiincreasethermalresistanceUse solid GNDplaneundermain heat sourceand exposegreen solder mask.This will givethe min thermalresistanceforthe MHSto dissipate heat.ADIConfidential113
CareriePCBBasicsViasVias (platedholes).Usedto connect layers.Formed by drilling or punching hole through PcB and plating the insideTypicallymuchlargerthansignaltracesBlindSignal Integrity Tip:PCBs introduce capacitance and change thecharacteristicimpedanceofatrace.DEVICEADIConfidential
PCB BasicsVias TvpesVias (platedholes)UsedtoconnectlayersTypicallymuchlargerthansignaltracesDEVICADIConfidential118