心跳血氧(AFE4490)

LED2DataAmb(LED2)DataLED1DataAmb(LED1)DataAFESPI(LED2tAmb)Data(LED1tAmb)Data+BufferûADC+TIA+Stage2GainPhotodiodeCPDDigitalFilterRxSPIInterfaceDiagnosticPDOpenorShortCableOffLEDOpenorShortLEDDriverLEDCurrentControlDACTimingControllerOSC8MHzDiagnosticSignalsAFELED5-VSupplyTxDriverSupply2.2-VSupplyLED2AMBLED2LED1AMBLED1FilterAFE4490–DECEMBER2012–REVISEDMAY2013IntegratedAnalogFront-EndforPulseOximetersCheckforSamples:AFE44901FEATURES23•Fully-IntegratedAnalogFront-Endfor•Package:CompactQFN-40(6mm×6mm)PulseOximeterApplications:•SpecifiedTemperatureRange:–40°Cto+85°C–FlexiblePulseSequencingandTimingControlAPPLICATIONS•Transmit:•MedicalPulseOximeterApplications–IntegratedLEDDriver•IndustrialPhotometryApplications(H-BridgeorPush/Pull)DESCRIPTION–110-dBDynamicRangeAcrossFullRange(EnablesLowNoiseatLowLEDCurrent)TheAFE4490isafully-integratedanalogfront-end(AFE)thatisideallysuitedforpulse-oximeter–LEDCurrent:applications.Thedeviceconsistsofalow-noise–ProgrammableRangesof50mA,75mA,receiverchannelwitha22-bitanalog-to-digital100mA,150mA,and200mA,converter(ADC),anLEDtransmitsection,andEachwith8-BitCurrentResolutiondiagnosticsforsensorandLEDfaultdetection.TheAFE4490isaveryconfigurabletimingcontroller.This–LowPower:flexibilityenablestheusertohavecompletecontrolof–100µA+AverageLEDCurrentthedevicetimingcharacteristics.Toeaseclocking–LEDOn-TimeProgrammabilityfromrequirementsandprovidealow-jitterclocktothe(50µs+SettleTime)to4msAFE4490,anoscillatorisalsointegratedthatfunctionsfromanexternalcrystal.Thedevice–IndependentLED2andLED1CurrentcommunicatestoanexternalmicrocontrollerorhostReferenceprocessorusinganSPI™interface.•ReceiveChannelwithHighDynamicRange:TheAFE4490isacompleteAFEsolutionpackaged–Input-ReferredNoise:inasingle,compactQFN-40package(6mm×50pARMS(at5-µAPDCurrent)6mm)andisspecifiedovertheoperating–13.5Noise-FreeBits(at5-µAPDCurrent)temperaturerangeof–40°Cto+85°C.–AnalogAmbientCancellationSchemewithSelectable1-µAto10-µAAmbientCurrent–LowPower:2.3mAat3.0-VSupply–RxSampleTime:50µsto250µs–I-VAmplifierwithSevenSeparateLED2andLED1ProgrammableFeedbackRandCSettings–IntegratedDigitalAmbientEstimationandSubtraction•IntegratedFaultDiagnostics:–PhotodiodeandLEDOpenandShortDetection–CableOn/OffDetection•Supplies:–Rx=2.0Vto3.6V–Tx=3.0Vor5.25V1Pleasebeawarethatanimportantnoticeconcerningavailability,standardwarranty,anduseincriticalapplicationsofTexasInstrumentssemiconductorproductsanddisclaimerstheretoappearsattheendofthisdatasheet.2SPIisatrademarkofMotorola.3Allothertrademarksarethepropertyoftheirrespectiveowners.PRODUCTIONDATAinformationiscurrentasofpublicationdate.Copyright©2012–2013,TexasInstrumentsIncorporatedProductsconformtospecificationsperthetermsoftheTexasInstrumentsstandardwarranty.Productionprocessingdoesnotnecessarilyincludetestingofallparameters.AFE4490SBAS602D–DECEMBER2012–REVISEDMAY2013(mA,max)(V)RANGEAFE4490QFN-40Bridge,push-pull50,75,100,150,and2003to5.25–40°Cto+85°CAFE4400QFN-40Bridge,push-pull503to3.60°Cto+70°CABSOLUTEMAXIMUMRATINGS(1)Overoperatingfree-airtemperaturerange,unlessotherwisenoted.VALUEUNITAVDDtoAVSS–0.3to+7VDVDDtoDGND–0.3to+7VAGNDtoDGND–0.3to+0.3VAnaloginputtoAVSSAVSS–0.3toAVDD+0.3VDigitalinputtoDVDDDVSS–0.3toDVDD+0.3VInputcurrenttoanypinexceptsupplypins(2)±7mAMomentary±50mAInputcurrentContinuous±7mAOperatingtemperaturerange–40to+85°CStoragetemperaturerange,Tstg–60to+150°CMaximumjunctiontemperature,TJ+125°CHumanbodymodel(HBM)±4000VJEDECstandard22,testmethodA114-C.01,allpinsElectrostaticdischarge(ESD)ratingsChargeddevicemodel(CDM)±1500VJEDECstandard22,testmethodC101,allpins(1)StressesbeyondthoselistedunderAbsoluteMaximumRatingsmaycausepermanentdamagetothedevice.Thesearestressratingsonly,anddonotimplyfunctionaloperationofthedeviceattheseoranyotherconditionsbeyondthoseindicatedunderRecommendedOperatingConditions.Exposuretoabsolute-maximum-ratedconditionsforextendedperiodsmayaffectdevicereliability.(2)Inputterminalsarediode-clampedtothepower-supplyrails.Inputsignalsthatcanswingbeyondthesupplyrailsmustbecurrent-limitedto10mAorless.THERMALINFORMATIONAFE4490THERMALMETRIC(1)RHA(QFN)UNITS40PINSθJAJunction-to-ambientthermalresistance35θJCtopJunction-to-case(top)thermalresistance31θJBJunction-to-boardthermalresistance26°C/WψJTJunction-to-topcharacterizationparameter0.1ψJBJunction-to-boardcharacterizationparameterN/AθJCbotJunction-to-case(bottom)thermalresistanceN/A(1)Formoreinformationabouttraditionalandnewthermalmetrics,seetheICPackageThermalMetricsapplicationreport,S