ValidationandTestingofDesignHardeningforSingleEventEffectsUsingthe8051MicrocontrollerAbstractWiththedearthofdedicatedradiationhardenedfoundries,newandnoveltechniquesarebeingdevelopedforhardeningdesignsusingnon-dedicatedfoundryservices.Inthispaper,wewilldiscusstheimplicationsofvalidatingthesemethodsforthesingleeventeffects(SEE)inthespaceenvironment.Topicsincludethetypesofteststhatarerequiredandthedesigncoverage(i.e.,designlibraries:dotheyneedvalidatingforeachapplication?).Finally,an8051microcontrollercorefromNASAInstituteofAdvancedMicroelectronics(IAμE)CMOSUltraLowPowerRadiationTolerant(CULPRiT)designisevaluatedforSEEmitigativetechniquesagainsttwocommercial8051devices.IndexTermsSingleEventEffects,Hardened-By-Design,microcontroller,radiationeffects.I.INTRODUCTIONNASAconstantlystrivestoprovidethebestcaptureofsciencewhileoperatinginaspaceradiationenvironmentusingaminimumofresources[1,2].Witharelativelylimitedselectionofradiation-hardenedmicroelectronicdevicesthatareoftentwoormoregenerationsofperformancebehindcommercialstate-ofthe-arttechnologies,NASA’sperformanceofthistaskisquitechallenging.Onemethodofalleviatingthisisbytheuseofcommercialfoundryalternativeswithnoorminimallyinvasivedesigntechniquesforhardening.Thisisoftencalledhardened-by-design(HBD).Buildingcustom-typeHBDdevicesusingdesignlibrariesandautomateddesigntoolsmayprovideNASAthesolutionitneedstomeetstringentscienceperformancespecificationsinatimely,cost-effective,andreliablemanner.However,onequestionstillexists:traditionalradiation-hardeneddeviceshavelotand/orwaferradiationqualificationtestsperformed;whattypesoftestsarerequiredforHBDvalidation?II.TESTINGHBDDEVICESCONSIDERATIONSTestmethodologiesintheUnitedStatesexisttoqualifyindividualdevicesthroughstandardsandorganizationssuchasASTM,JEDEC,andMIL-STD-883.Typically,TID(Co-60)andSEE(heavyionand/orproton)arerequiredfordevicevalidation.SowhatisuniquetoHBDdevices?Asopposedtoa“regular”commercial-off-the-shelf(COTS)deviceorapplicationspecificintegratedcircuit(ASIC)wherenohardeninghasbeenperformed,oneneedstodeterminehowvalidatedisthedesignlibraryasopposedtodeterminingthedevicehardness.Thatis,byusingtestchips,canwe“qualify”afuturedeviceusingthesamelibrary?ConsiderifVendorAhasdesignedanewHBDlibraryportabletofoundriesBandC.Atestchipisdesigned,tested,anddeemedacceptable.NinemonthslateraNASAflightprojectentersthemixbydesigninganewdeviceusingVendorA’slibrary.Doesthisdevicerequirecompleteradiationqualificationtesting?Toanswerthis,otherquestionsmustbeasked.Howcompletewasthetestchip?Wastheresufficientstatisticalcoverageofalllibraryelementstovalidateeachcell?IfthenewNASAdesignusesapartiallyorinsufficientlycharacterizedportionofthedesignlibrary,fulltestingmightberequired.Ofcourse,ifpartoftheHBDwasrelyingoninherentradiationhardnessofaprocess,someofthetests(likeSELintheearlierexample)maybewaived.Otherconsiderationsincludespeedofoperationandoperatingvoltage.Forexample,ifthetestchipwastestedstaticallyforSEEatapowersupplyvoltageof3.3V,isthedataapplicabletoa100MHzoperatingfrequencyat2.5V?Dynamicconsiderations(i.e.,nonstaticoperation)includethepropagatedeffectsofSingleEventTransients(SETs).Thesecanbeagreaterconcernathigherfrequencies.Thepointoftheconsiderationsisthatthedesignlibrarymustbeknown,thecoverageusedduringtestingisknown,thetestapplicationmustbethoroughlyunderstoodandthecharacteristicsofthefoundrymustbeknown.Ifalltheseareapplicableorhavebeenvalidatedbythetestchip,thennotestingmaybenecessary.AtaskwithinNASA’sElectronicPartsandPackaging(NEPP)Programwasperformedtoexplorethesetypesofconsiderations.III.HBDTECHNOLOGYEVALUATIONUSINGTHE8051MICROCONTROLLERWiththeirincreasingcapabilitiesandlowerpowerconsumption,microcontrollersareincreasinglybeingusedinNASAandDODsystemdesigns.ThereareexistingNASAandDoDprogramsthataredoingtechnologydevelopmenttoprovideHBD.Microcontrollersareonesuchvehiclethatisbeinginvestigatedtoquantifytheradiationhardnessimprovement.Examplesoftheseprogramsarethe8051microcontrollerbeingdevelopedbyMissionResearchCorporation(MRC)andtheIAμE(thefocusofthisstudy).AstheseHBDtechnologiesbecomeavailable,validationofthetechnology,inthenaturalspaceradiationenvironment,forNASA’suseinspaceflightsystemsisrequired.The8051microcontrollerisanindustrystandardarchitecturethathasbroadacceptance,wide-rangingapplicationsanddevelopmenttoolsavailable.Therearenumerouscommercialvendorsthatsupplythiscontrollerorhaveitintegratedintosometypeofsystem-on-a-chipstructure.BothMRCandIAμEchosethisdevicetodemonstratetwodistinctlydifferenttechnologiesforhardening.TheMRCexampleofthisistousetemporallatchesthatrequirespecifictimingtoensurethatsingleeventeffectsareminimized.TheIAμEtechnologyusesultralowpower,andlayoutandarchitectureHBDdesignrulestoachievetheirresults.ThesearefundamentallydifferentthantheapproachbyAeroflex-UnitedTechnologiesMicroelectronicsCenter(UTMC),thecommercialvendorofaradiation–hardened8051,thatbuilttheir8051microcontrollerusingradiationhardenedprocesses.Thisbroadrangeoftechnologywithinonedevicestructuremakesthe8051anidealvehiclefo