高速电路信号完整性测试,分析和验证

2008-6-1312008-6-132ƒƒƒƒ2008-6-133ƒƒƒƒ2008-6-134+-Rcv+-Rcv+-Rcvpath+-+-path+-+-path+-+-TestpointTx+-Tx+-Tx+-TestpointTestpointTx+-path+-+-path+-+-path+-+-TestpointTestpointTestpointTestpointTestpointTestpoint1234Testpoints(functionalcheck;debug)2008-6-135ƒƒƒƒ2008-6-136ƒƒ2008-6-137defineschdesignPCBcadsidebugSISISISISISI2008-6-138ƒƒApplication2008-6-139ƒƒƒ2008-6-13102008-6-1311ƒƒ2008-6-1312DCKQ2008-6-1313ƒ2008-6-1314ƒƒ2008-6-1315ƒ–––ƒƒƒƒƒƒ2008-6-1316ƒƒƒƒƒƒƒ2008-6-1317“OPEN”“CLOSE”path+-+-Tx+-path+-+-path+-+-+-RcvEQUALIZERƒ/ƒ2008-6-1318:¾()¾¾PRBSTaps2008-6-1319T1T2Tj=T1+T22008-6-1320ƒ––ƒ–ƒ–ƒ2008-6-1321==(RN)(DN)(PN)(DDN)(TN)(TJ)(DCD)(DDJ)(PJ)(DJ)(RJ)(BER)BER2008-6-1322ƒBER2008-6-13232008-6-13242008-6-13252008-6-13262008-6-13272008-6-13282008-6-13292008-6-1330TEABREAK!2008-6-13312008-6-1332ƒƒƒƒƒ2008-6-1333ƒƒPROBELOADINGCANIMPACTBOTH2008-6-13342008-6-13352008-6-1336ƒƒ2008-6-1337ƒƒ2008-6-1338ƒƒVCCCCRCPROBERPCPREVINf0=12RCCCGain=-(RC||RP)REf0=2(RC||RP)(CC+CP)1Gain=-RCRE2008-6-1339Toomuchloadingandthesignaldoesn’tworkanymore.2008-6-1340ƒCMOS710XƒCMOS=24pF/Load=3.0pFPerGateƒ2008-6-134124pF/Load=3.0pFPerGate1Note:CMOSgatesmaynotdrive50Ωdividerprobes.1XPassive(100pF)10XPassive(10pF)50DividerProbe1(0.15pF)ActiveProbe(1.0pF)~0.05EquivalentGates~33EquivalentGates~3.3EquivalentGates~0.3EquivalentGates2008-6-1342Frequency100M10M1M100k10k1k1001011001k10k100k1M10M100M1G10GZo0.15pF/500ΩActive1.0pF/1MΩ1XPassive100pF/1MΩ10XPassive10pF/10MΩInputImpedance10XPassiveprobeloadinggoesto159at100MHzZ=1/2PifC2008-6-1343100MHz-500MHz3.5ns-700ps13pF-8pF10M3GHz-9GHz120ps-40ps1pF-0.15pF500500MHz-4GHz700ps-100ps2pF-0.4pF10M-100k10XPassiveProbeZ0PassiveProbe(LowCapacitance)ActiveProbeTypeBandwidthInputCInputRRiseTime1GHz-16GHz30ps-350ps.1pF-2pF200k-100kDifferentialProbe2008-6-1344ƒƒ……ƒƒƒƒ–ƒƒƒƒ……2008-6-1345ƒ––––ƒ–––ƒ––ƒƒ……ƒƒƒƒƒƒƒƒ2008-6-1346ƒ–ƒƒ––ƒ––ƒ–––ƒƒ–––ƒ–––ƒ––ƒ–––2008-6-13470dB6divat50kHz-3dB4.2divatbandwidthVV0.7070.707V,V,ffBWBW2008-6-13482008-6-1349DigitalSquareWave–OddFourierSums-101050100Fundamental(1stHarmonic)5thHarmonic3rdHarmonicFourierSquareWave(1st-5thH)2008-6-1350ƒ––––v.s.()()22??????????????????????+=()()nsnsns41.11122=+=???????()()nspsns06.1350122=+=???????2008-6-1351250MHzBW1GHzBW2008-6-13521st3rd5thTr0.080Tr0.040Tr0.0255Gb/s2008-6-13532008-6-1354Assumption:Frequency=0.4/Rise-Time(20%-80%)RequiredBWfor5%measurementaccuracy=Frequencyx1.2Actualmeasurement30pswithin5%accuracy2008-6-1355ƒƒ2008-6-1356Aliasing2008-6-135790%10%2008-6-1358ƒƒƒƒƒƒƒƒƒƒƒ2008-6-1359ƒƒƒƒƒƒƒƒƒƒ2008-6-1360Debug/Debug/VerificationVerificationCharacterizeCharacterizeLabLabComplianceComplianceElectricalElectricalDataDataRateRate50Mb/s50Mb/s40Gb/s40Gb/s10Gb/s10Gb/s5Gb/s5Gb/s2.5Gb/s2.5Gb/sETRTETPassivePassiveTransmissionTestTransmissionTestInterconnectInterconnectSystemSystemSubsystem/DeviceSubsystem/DeviceMfgTestMfgTestComplianceComplianceRTETRTETRTET2008-6-1361/ƒƒ2008-6-1362BERTƒƒ2008-6-1363TEABREAK!2008-6-13642008-6-1365+-Rcv+-Rcv+-Rcvpath+-+-path+-+-path+-+-TestpointTx+-Tx+-Tx+-TestpointTestpointTx+-path+-+-path+-+-path+-+-TestpointTestpointTestpointTestpointTestpointTestpoint1234Testpoints(functionalcheck;debug)2008-6-1366ffLVDSffPCI-Express2008-6-1367ƒ–––ƒ–––ƒ––ƒ–––2008-6-13682008-6-1369+-+-Rcv+-+-Rcv+-+-Rcv+-+-RcvTx+-Tx+-Tx+-Tx+-ƒ––––2008-6-13703m??,2.5×10100.03m??2008-6-1371ƒ–––––ƒ––ƒ–––ƒ–2008-6-1372VOH~2.4VVOL~1.6VA3isa4-bitbusA2isan8-bitbusA3(3)A3(2)A3(1)A3(0)A2(7)A2(6)A2(5)A2(4)A2(3)A2(2)A2(1)A2(0)properlyterminatedproperlyterminatedLVPECLLVPECLLVPECL2008-6-1373A3isa4bitbusA3(3)signalline3inchstubtraceerrorPCB2008-6-13742008-6-13752008-6-1376ƒClockInputtholdtsetupDInput2008-6-1377ƒ–ƒ–ƒ–ƒ–ƒ–ƒ–ƒ2008-6-13780.03m??+-+-Rcv+-+-Rcv+-+-Rcv+-+-RcvTx+-Tx+-Tx+-Tx+-2008-6-1379???????????????=??????????????2008-6-1380ƒƒProbabilityAcquisition(Sweep)TimeofCaptureAcquisition(Sweep)Time+System(Sweep)HoldoffTime=2008-6-13812008-6-13822008-6-1383ƒƒƒ2008-6-1384A3isa4bitbusA2isa8bitbusA3(0)signallineA2(0)signalline22pfƒƒ2008-6-1385ƒƒƒƒƒ2008-6-13862008-6-1387ƒƒƒƒƒ2008-6-1388ƒ2008-6-1389ffLVDSffPCI-ExpressUSB2008-6-13908:PCBIC:SerDesSerDesDeviceAICBGATxRxTxRxSerDesSerDesDeviceBACSerDesSerDesDeviceATxRxTxRxSerDesSerDesDeviceB:SerDesSerDesDeviceATxRxTxRxSerDesSerDesDeviceB/SerDesSerDesDeviceATxRxTxRxSerDesSerDesDeviceB:2008-6-1391ƒLVDSƒLVDS–ƒLVDS2008-6-1392ƒƒƒƒƒƒƒVCM=(Ch1+Ch3)/2=Math1VDIFF=Ch1-Ch3=Math2D-=Ch3D+=Ch12008-6-13932008-6-1394ƒSMA–ƒ:ƒDUT50100ƒƒDeskewVCM=(Ch1+Ch3)/2=Math1VDIFF=Ch1-Ch3=Math2SerDesSerDesCh1Ch3D-=Ch3D+=Ch12008-6-1395TransmissionChannelSerDesSerDesDeviceAPackageBGAPinsECBCopperDifferentialTracesTxRxTxRxSerDesSerDesDeviceBLaneMechanicalExample12008-6-1396ƒƒƒƒVDIFF=Ch1RxVDIFFChannelChannelFromExample2FromExample2ActiveProbeCh1Tx2008-6-1397ƒƒƒƒDCM+DCM-D-=Ch3D+=Ch1VCM=(Ch1+Ch3)/2=Math1VDIFF=Ch1-Ch3=Math2AsymmetricSignalExampleChannelChannelTxRxD+D-Ch1Ch3ActiveProbeActiveProbe2008-6-1398ƒƒƒ2008-6-1399ffLVDSffPCI-ExpressUSB2008-6-13100199619982000200220042006StorageAreaNetwork(SAN)FibreChannel1.0625GbpsFibreChannel2.125GbpsInfiniBand2.5Gbps1,4,12chLocalAre