Addressing the Gap in the 50G C2M Speciﬁcaons

AddressingtheGapinthe50GC2MSpecifica7ons

AliGhiasiGhiasiQuantumLLC

IEEE802.3bsVancouver

March12,2017

q  RichMellitz– Samtecq  YasuoHidaka–Fujitsu

A.Ghiasi IEEE802.3bsTaskForce 2

Contributor/Supporter

Overviewq  InsupportofD3.0commentsGhiasi94,95,96,97andMellitz77and78q  UpdatedsimulaSonevaluatesfarendeyeopeningfortheTEchannelsasfuncSonofICNq  UpdatedsimulaSonsnowincluderesultsfromYamaichiQSFP28connectorwithsignificantlylower

crosstalkthanlimitsofCL92q  ThebasesimulaSonshaveconsistedof

–  6TEhypothe7calchannelswithcrosstalk~1/6ofMDIdefini7onofclause92andreferencedbyCL120.E–  2Ciscochannelswithnocrosstalk

q  Historyofcommentsonthisissue–  ThisissuewasfirstraisedwithComment128againstP802.3bsdraR1.4thatmatedboardofCL92

crosstalkisexcessiveinsupportof50GCucabling–  Comments83and86aresubmiUedagainstD2.0relatedtoexcessivecrosstalknotconsideredinthebaselineC2M–  Comments135againstD2.1relatedtoexcessivecrosstalknotconsideredinthebaselineC2M

q  Clause120.especificaSonfarendeyeopeningcan’tbemetascurrentlydefined–  Aclause120.dtransmiUerwithmaxcrosstalkasdefinedbyclause92MDIcanonlysupportabout7.5dB

forgoodchannelsandnot10.2dB!–  AnengineeredC2MwithimprovetransmiUercoupledwithalowercrosstalkMDIcansupport10.2dB

objec7ve!

A.Ghiasi 3IEEE802.3bsTaskForce

50GMatedBoardReferencesLegacyCL92MCB/HCBSpecifica7ons

q  CurrentlyCL120E.4.1MCB/HCBspecificaSonsreferences–  CL92.11.1forHCBspecifica7ons–  CL92.11.2fortheMCBspecifica7ons–  CL92.11.3.6definesmatedtextfixtureICN

•  MDFEXTof4.8mVisexcessivefor50GPAM4link!

A.Ghiasi 4IEEE802.3bsTaskForce

BasesfortheMatedMCB/HCBMDFEXT/MDNEXTinCL92

q  QSFP+connectorprovidedbasesfortheCL92MDFEXTandMDNEXT–  QSFP28doesprovideslightimprovementbutin802.3cddecidedtostaywiththeselegacylimits–  hUp://www.ieee802.org/3/bj/public/sep12/ghiasi_3bj_01a_0912.pdf

A.Ghiasi 5

MCB-HCB Crosstalk10.3125 GBdICN (mV)

25.78 GBdICN (mV)

28.0 GBd ICN(mV)

Rise Time 20-80% (ps) 24.000 9.600 8.840

MDNEXT 0.323 1.390 1.612

MDFEXT 3.593 4.562 4.673

ICN 3.607 4.769 4.943

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IL, dB MDNEXT MDFEXT

IEEE802.3bsTaskForce

Hypothe7calChannelUsedforC2MAnalysisHasSignificantlyLowerNEXT/FEXT

q  CDAUI-8/CCAUI-4basechannels–  hUp://www.ieee802.org/3/bs/public/adhoc/elect/24Aug_15/dallaire_01_082415_elect.pdf

A.Ghiasi 6

Testcase3and5HavingalosssimilartomatedboardareUsedforCrosstalkAnalysis


CrosstalkforC2MTestCase3and5q MatedboardhadnoNEXTandwithexcellentFEXT

–  hUp://www.ieee802.org/3/bs/public/channel/TEC/shanbhag_3bs_01_1014.pdf–  C2Marebasedonchannelswith5-7xlowercrosstalkthanmatedboardreferencedcurrently!

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TestCase3SMTConnectorMDFEXT=0.698mV

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TestCase5PressFitConnectorMDFEXT=1.044mV


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YamaichiQSFP28q  BasedonmeasuredcurrentgeneraSonYamaichiQSFP28withlowercrosstalk

–  Matedboardlossisonly2.8dBexaspera7ngthecrosstalkvalue–  MDNEXT=0.523mV(RX1-RX4used4x)MDFEXT=2.49mV[NEXT/FEXTaggressor1200/900mVusedforsimula7on]–  MDNEXT=0.392mV(RX1-RX4used4x)MDFEXT=2.49mV[NEXT/FEXTaggressor900/900mVmoreinlineforC2M]–  MDNEXT=0.523mV(RX1-RX4used4x)MDFEXT=3.32mV[NEXT/FEXTaggressor1200/1200mVperCL92]

A.Ghiasi IEEE802.3BSTaskForce 8

RecentDataonMDICrosstalkq  Assuming1200mVfortheFEXT/NEXT

–  worstcaseMDFEXT=3.24mVRMSandMDNEXT=0.78mVRMS–  ProposingMDFEXT=3.4mVandPSXT=3.5mVtosupportallconnectors


QSFP28 µQSFP28

QSFP-dd

hUp://www.ieee802.org/3/bs/public/17_03/dudek_3bs_01_0317.pdf hUp://www.ieee802.org/3/cd/public/Mar17/palkert_3cd_03_0317.pdf

hUp://www.ieee802.org/3/cd/public/Mar17/tracy_3cd_01_317.pdf

BaselineC2MSimula7onSummary

q  BaselineC2MsimulaSonCOManalysisforthehypotheScalchannelswith5-7xlowercrosstalkdoesn’tevenhavemarginevenwithCTLE+TXFIR+LFEQat1E-5BER!–  Increasingcrosstalkby5-7xonchannelsbelowwithcurrentlinkconfigura7onandequalizerwill

bedetrimental!–  SummaryresultsfromhUp://www.ieee802.org/3/bs/public/adhoc/elect/24Aug_15/

dallaire_01_082415_elect.pdf

A.Ghiasi IEEE802.3bsTaskForce 10

IEEECOMRev165Parameters

A.Ghiasi 11hUp://www.ieee802.org/3/cd/public/channel/mellitz_3cd_01_1116_COM.zip

1AddsxyzmmPCB,0noextraPCB


ImprovetransmiUerusesA_dd=0.015UIandSNR_TX=33dB

HostIC[1230]

HowRealis7cisLowerJiUerTransmiUer

q  Improvetransmieer–  A_dd=0.015UIreducedfrom

0.02UI–  Sigma_RJ=0.01UIunchanged–  SNRincreasedto33dB–  Packagetracereducedto24

mmq  ButothercombinaSonmay

alsoyieldthesameresults–  AddingTP0aeyeopeningtest

couldpoten7allyallowtradeoffbetweenaboveparametersaswellotherparameters.


0.005

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A_dd(UI)

J4(UI)

A_ddasfunctionofJ4andJRMS

JRMS=0.015 JRMS=0.016 JRMS=0.017 JRMS=0.018 JRMS=0.019 JRMS=0.02 JRMS=0.021 JRMS=0.022 JRMS=0.023 JRMS=0.024 JRMS=0.025

Cl120.dlimit

ImproveTX

TP1aOutputasfunc7onofChannelILandICN

q  CollocaSonofresultswithmoredatapointsfromhep://www.ieee802.org/3/bs/public/adhoc/elect/30Jan_17/ghiasi_01_013017_elect.pdf

q  ChannelforthisanalysisistheTE4”stackedhypotheScalchannelswithaddiSonallossaddedperdefiniSonofCL92

hep://www.ieee802.org/3/bs/public/channel/TEC/shanbhag_3bs_01_1014.pdf

q  Resultsareforworstcaseandimprovedtransmieer–  WorstTXPKG=30mm,SNR=31,A_dd=0.02UI–  BeUerTXPKG=24mm,SNR=33,A_dd=0.015UI

q  WithCL92matedboardandstandardTXonly7.8dBchannelcanbesupported

q  ImproveTXwithlowercrosstalkmatedboardICNof2.9mVcansupportcurrentobjecSveof10.2dB

–  Otherconfigura7onmayalsosupport10.2dBobjec7ve

q  StandardTXwithCL92can’tsupport10.2dBandCL120.eshouldsuggestit!


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ICN-StdTX

ICN-betterTX

VEO-StdTX

VEO-betterTX

TP1aResultsforYamaichiQSFP28q  10.2dBchannelscanbesupportedwithnextGenQSFP28havinglowerICN

–  StdtransmieerPKG=30mm,A_dd=0.02,SNR=31dB,PKG_Zc=85Ω–  TX2PKG=24mm,A_dd=0.015,SNR=33dB,PKG_Zc=85Ω–  TX3PKG=30mm,A_dd=0.02,SNR=32.5dB,PKG_Zc=90Ω


ResultswithStdTX:VEO*=26.9mV(failing),ICN=1.435mV,PeakISI=9.77mV,MDFEXTPeak=2.6mV,MDNEXT=0.51,ILD(FOM)=0.042,COM=4.97dBResultswithImproveTX2:VEO*=31.58mV(failing),ICN=1.434mV,PeakISI=11.07mV,MDFEXTPeak=2.6mV,MDNEXT=0.51,ILD(FOM)=0.042,COM=5.97dBResultswithImproveTX3:VEO*=29.3mV(failing),ICN=1.434mV,PeakISI=10.2mV,MDFEXTPeak=2.12mV,MDNEXT=0.51,ILD(FOM)=0.042,COM=5.56dBVEOatTP1aneedtobereducedto30mVtosupport10.2dBchannels.

TP4/TP5ResultsforYamaichiQSFP28*

q  10.2dBchannelscanbesupportedwithanexisSngQSFP28withlowerICN–  StdtransmiUerPKG=[612]mm,A_dd=0.02,SNR=31dB–  ImprovetransmiUerPKG=[612]mm,A_dd=0.015,SNR=33dB


ResultswithStdTX:TP4:VEO*=67.8mV(failing),ICN=1.435mV,PeakISI=22.22mV,MDFEXTPeak=5.5mV,MDNEXT=1.28,ILD(FOM)=0.044,COM=4.99dBTP5:VEO=28.3mV(failing)ResultswithImproveTX:TP4:VEO*=71.2mV(failing),ICN=1.434mV,PeakISI=11.07mV,MDFEXTPeak=5.5mV,MDNEXT=1.28,ILD(FOM)=0.042,COM=5.99dBTP5:VEO=33.2mVResultsforimprovetransmieerwithA_fe=0.9,A_ne=1.26(doublecrosstalk):VEO*=67.5mV(failing),ICN=2.64mV,PeakISI=22.2mV,MDFEXTPeak=10.54mV,MDNEXT=2.61,ILD(FOM)=0.045,COM=5.56dBTP5:VEO=31.67mVLoweringEHatTP4from90mVto70mVshouldbesufficientfor30mVatTP5!

*Matedboardhadlossofonly2.8dBloss,1dBextradBaddtoincreaselossto3.8dBandmayresultinexcesscrosstalk.

TP4ResultsfordiminicoMTFwithYamaichiQSFP28Crosstalk

q  10.2dBchannelscanbesupportedwithanexisSngQSFP28withlowerICN–  StdtransmiUerPKG=[612]mm,A_dd=0.02,SNR=31dB–  ImprovetransmiUerPKG=[612]mm,A_dd=0.015,SNR=33dB


ResultsforstdtransmieerwithA_fe=0.9,A_ne=1.26:VEO*=67.7mV(failing),ICN=2.9mV,PeakISI=24.1mV,MDFEXTPeak=12.2mV,MDNEXT=2.95,ILD(FOM)=0.055,COM=5.8dBTP5:VEO=31.2mVResultsforimprovetransmieer:TP4:VEO*=81.6mV(failing),ICN=2.927mV,PeakISI=11.07mV,MDFEXTPeak=6.38mV,MDNEXT=1.47,ILD(FOM)=0.055,COM=6.38dBTP5:VEO=38.2mVResultsforimprovetransmieerwithA_fe=0.9,A_ne=1.26(doublecrosstalk):VEO*=77.3mV(failing),ICN=2.927mV,PeakISI=24.1mV,MDFEXTPeak=12.2mV,MDNEXT=2.95,ILD(FOM)=0.055,COM=5.9dBTP5:VEO=36.24mVLoweringEHatTP4from90mVto70mVshouldbesufficientfor30mVatTP5!

Summaryq  802.3bsC2MsimulaSoninsupportof50G/lanePAM4werebasedonaTEhypotheScalconnectorwith~6x

lowerFEXTandNEXTanddoesnotprovidedtechnicalfeasibilitywithcurrentMDIdefiniSon–  Currently10.2dBchannelcanbesupportedonlywithnocrosstalk!

q  P802.3bsclause120.EwhichreferenceCL92hasexcessiveamountofMDFEXT(4.8mV)andMDNEXT(1.8mV)whichdoesnotsupport10.2dBchannelassumingclause120.dtransmieer

q  ArepresentaSveQSFP28fromYamaichiwith~40%lowercrosstalkthanlimitsofCL92MDIcansupport10.2dBchannels

q  Basedonstrongfeedbackreceivedduringadhoccallfollowingconstrainwillsupport10.2dBC2M:–  TP1acompliancecanbemetbyfollowingrequirements

•  NeedtoreduceVEOto30mVfrom32mV•  Combina7onofbeUerpackage,lowerjiUer,lowercrosstalk,improveSNR,etccoulddeliver30mV

–  TP5at30mVdrivenfromansmallICinthemoduleshouldnotbelimi7ngfactor–  TP4withVEOof90mVisexcessivelylarge,notconsistenttodeliver30mV,andwilladdburdenonthemoduleIC

•  ReduceVEOfrom90mVto70mV–  ReducematedboardcrosstalkMDFEXT=3.4mVandPSXT=3.5mV(assuming1200mVFEXT/NEXT)

q  DesigningandbuildingC2Mproductwith10.2dBwillbesomewhathitormissmeeSngTP1agivenILD,reflecSons,andlackofmargin–  Addinganinforma7veTP0atestpointwithVEOof90mVcanprovideaddi7onalconfidencelevelmee7ngTP1a.

A.Ghias 17IEEE802.3bsTaskForce

Addressing the Gap in the 50G C2M Speciﬁcaons

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