Issue with 50G PAM4 C2M Specification - IEEE-SA - Working...
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Issue with 50G PAM4 C2M Specification Ali Ghiasi Ghiasi Quantum LLC IEEE 802.3cd Task Force Meeting Jan 11th, 2017
Transcript of Issue with 50G PAM4 C2M Specification - IEEE-SA - Working...
Issuewith50GPAM4C2MSpecification
AliGhiasiGhiasi QuantumLLC
IEEE802.3cdTaskForceMeeting
Jan11th,2017
q RichMellitz – Samtecq Yasuo Hidaka– Fujitsu
A.Ghiasi IEEE802.3CDTaskForce 2
Contributor/Supporter
Backgroundq Insupportofcomment116againstP802.3cdD1.1q TheIEEE802.3bsC2Msimulationshavenotdemonstratedoperationover10.2dBchannelwithmax
FEXT/NEXTq Thebasesimulationshaveconsistedof
– 6TEhypotheticalchannelswithcrosstalk~1/6ofMDIdefinitionofclause92andreferencedbyCL120.E– 2Ciscochannelswithnocrosstalk
q Historyofcommentsonthisissue– ThisissuewasfirstraisedwithComment128againstP802.3bsdraft1.4thatmatedboardofCL92
crosstalkisexcessiveinsupportof50GCucabling– Comments83and86aresubmittedagainstD2.0relatedtoexcessivecrosstalknotconsideredinthebaselineC2M– Comments135againstD2.1relatedtoexcessivecrosstalknotconsideredinthebaselineC2M
q Severaltimeshaverequestedrepresentativeclause92MDIdataformoreaccuratesimulationbutnonewdatahasbeenprovided
q Clause92MDIdatawithoutcrosstalkshowjustaboutpassesverticaleyeopening– Thereisverystrongindicationthatclause120.efailsbadlyfarendeyeopening– HavingMDIdatawhichincludecrosstalkdatawillimprovethesimulationresultsandaccuracy.
A.Ghiasi 3IEEE802.3cdTaskForce
50GMatedBoardReferencesLegacyCL92MCB/HCBSpecifications
q CurrentlyCL120E.4.1MCB/HCBspecificationsreferences– CL92.11.1forHCBspecifications– CL92.11.2fortheMCBspecifications– CL92.11.3.6definesmatedtextfixtureICN
• MDFEXTof4.8mVisexcessivefor50GPAM4link!
A.Ghiasi 4IEEE802.3cdTaskForce
BasesfortheMatedMCB/HCBMDFEXT/MDNEXTinCL92
q QSFP+connectorprovidedbasesfortheCL92MDFEXTandMDNEXT– QSFP28doesprovideslightimprovementbutin802.3cddecidedtostaywiththeselegacylimits– http://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 MDNEXTMDFEXT
IEEE802.3cdTaskForce
HypotheticalChannelUsedforC2MAnalysisHasSignificantlyLowerNEXT/FEXT
q CDAUI-8/CCAUI-4basechannels– http://www.ieee802.org/3/bs/public/adhoc/elect/24Aug_15/dallaire_01_082415_elect.pdf
A.Ghiasi 6
Testcase3and5HavingalosssimilartomatedboardareUsedforCrosstalkAnalysis
IEEE802.3cdTaskForce
CrosstalkforC2MTestCase3and5q MatedboardhadnoNEXTandwithexcellentFEXT
– http://www.ieee802.org/3/bs/public/channel/TEC/shanbhag_3bs_01_1014.pdf– C2Marebasedonchannelswith5-7xlowercrosstalkthanmatedboardreferencedcurrently!
A.Ghiasi 7
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IL, dB MDNEXT MDFEXT
TestCase3SMTConnectorMDFEXT=0.698mV
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TestCase5PressFitConnectorMDFEXT=1.044mV
IEEE802.3cdTaskForce
BaselineC2MSimulationSummary
q BaselineC2MsimulationCOManalysisforthehypotheticalchannelswith5-7xlowercrosstalkdoesn’tevenhavemarginevenwithCTLE+TXFIR+LFEQat1E-5BER!– Increasingcrosstalkby5-7xonchannelsbelowwithcurrentlinkconfigurationandequalizerwill
bedetrimental!– Summaryresultsfrom
http://www.ieee802.org/3/bs/public/adhoc/elect/24Aug_15/dallaire_01_082415_elect.pdf
A.Ghiasi IEEE802.3cdTaskForce 8
ResultswithMTFTestBoardq TP1aresponseoftheMTFtestboard+150mmtracehasoutputVEO=32.2mVwithout
anycrosstalkjustpassesthelimitinCL120.E!– MTFboardhttp://www.ieee802.org/3/bs/public/channel/mccom/diminico_3bs_01_0516.s4p
A.Ghiasi IEEE802.3CDTaskForce 9
UsingCOMversion165ResultsforMTFlikechannelwithIL_fit=10.25dBVEO=32.2mV,ICN=0mV,PeakISI=10.8mV,MDFEXTPeak=0mVCOM=5.13dB
4”TEStacked50GChannelMeetingMTFq BasedonTEhypotheticalconnectorwithIL_Fit of4.3dBbuthavingMDFEXTp-p=2.37mV
(MDFEXTRMSforBER1E-5=2.37/4.26=0.56mV)– ToaccountforworstcaseMDFEXT=4.8mVandMDNEXT=1.8mV(PSXT=5.13mVRMS)A_fe ininCOMwasadjusted
from0.45to4.12inordertogetMDFEXTp-pof21.84mVequivalenttoPSXTof5.13mVRMSpertable92-13– http://www.ieee802.org/3/bs/public/channel/TEC/shanbhag_3bs_01_1014.pdf
A.Ghiasi IEEE802.3cdTaskForce 10
UsingCOMversion165ResultsforMTFlikechannelwithIL_fit=4.3dBResultsforA_fe=0.45:VEO=58mV,ICN=1.237mV,PeakISI=21.5mV,MDFEXTPeak=2.37mVCOM=5.01dBResultswithA_fe=4.12:VEO=42.5mV,ICN=1.237mV,PeakISI=21.5mV,MDFEXTPeak=21.88mVCOM=3.36dB
10”TEStacked50GChannelq BasedonTEhypotheticalconnectorwithIL_Fit of8.8dBshyofclause120.Elossof10.2dB
– Sincethe4”and10”TEstackboardshavesimilarconstructionwithexceptionofonewithlongertrace,thecalibratedA_fe crosstalkofthe4”boardisusedforthe10”board
– http://www.ieee802.org/3/bs/public/channel/TEC/shanbhag_3bs_01_1014.pdf
A.Ghiasi IEEE802.3cdTaskForce 11
UsingCOMversion165ResultsforMTFlikechannelwithIL_fit=4.3dBResultsforA_Fe=0.45:VEO=37.5mV,ICN=0.759mV,PeakISI=11.55mV,MDFEXTPeak=1.39mVCOM=5.28dBResultswithA_Fe=4.14:VEO=28.2mV(failing),ICN=0.759mV,PeakISI=11.55mV,MDFEXTPeak=12.89mVCOM=3.65dB
10”TEStacked50GChannelq BasedonTEhypotheticalconnectorwithIL_Fit of8.8dBshyofclause120.Elossof10.2
dB,toincreasethelossto31mmofPCBtraceperclause120isadded– Sincethe4”and10”boardaresimilarwithexceptionofthelongertrace,calibratedA_fe
crosstalkiskeptat4.14forthe10”board+31mmPCBtrace
A.Ghiasi IEEE802.3cdTaskForce 12
UsingCOMversion165ResultswithA_fe=4.14:VEO=21.2mV(failing),ICN=0.759mV,PeakISI=11.38mV,MDFEXTPeak=12.84mV,COM=3.03dB
QSFPMTF+CrosstalkfromTE4”Stackedq QSFPMTF(diminico_3bs_01_0516.s4p)doesnothaveanycrosstalkdata
– TE4”stackedwithIL_Fit of⋍4.3isusedasthecrosstalksource– 150mmofPCBtraceisaddedperclause92toincreasethelossto10.2dB– ThecalibratedcrosstalksourceisA_fe=4.14
A.Ghiasi IEEE802.3cdTaskForce 13
UsingCOMversion165ResultswithA_fe=4.14:VEO=10.9mV(failing),ICN=1.237mV,PeakISI=10.7mV,MDFEXTPeak=20.87mVCOM=1.43dB
Summaryq P802.3cdclause135G50GAUI-1and100GAUI-2arereferencingP802.3bsclause120.Ewhichreference
CL92havingverylargeamountofMDFEXT(4.8mV)andMDNEXT(1.8mV)q 802.3bsC2Msimulationinsupportof50G/lanePAM4werebasedonaTEhypotheticalconnectorwith
~6xlowerFEXTandNEXTanddoesnotprovidedtechnicalfeasibilitywithcurrentMDIdefinitionq IEEEP802.3bsandcdneedtocollectivelyworktogethertoresolvethisissuesoonerthanlaterto
minimizetheimpact– Havingrepresentativeclause92MDIdatawithcrosstalkwillbeveryhelpful
q Potentialareaneedtobeconsideredinordertoclosethemajorholeinclause120.Especification– Clause92MDIcrosstalkwasbasedonthedataIpresentedin802.3bjover5yearsagoneedtobetighten
by~3xforrobustPAM4operation– TEhypotheticalconnectorisproofthatimprovedconnectorcanbedeveloped,couldTEorotherpossibly
developanimprovedconnectorcompatiblewithCL92MDI– CurrentfarendeyeopeningofEW1E-5=0.22andEH1E-5=32mVhasverylittleroomforfurthertightening– Tightentransmitterparameterssuchasjitterandrisetimecanprovidedsomereliefbutnotenoughto
closethelinkbudget– UseCOMasthetooltotradeoffloss,crosstalk,andISInowthatthereareseveralMDI’seachwith
somewhatdifferentcharacteristicsaretargetedfor802.3bs/cdimplementation– Defineamorepowerfulequalizerforthechip-to-module.
A.Ghiasi 14IEEE802.3cdTaskForce
