ADXL345英文

3-Axis,±2g/±4g/±8g/±16gDigitalAccelerometerADXL345Rev.BInformationfurnishedbyAnalogDevicesisbelievedtobeaccurateandreliable.However,noresponsibilityisassumedbyAnalogDevicesforitsuse,norforanyinfringementsofpatentsorotherrightsofthirdpartiesthatmayresultfromitsuse.Specificationssubjecttochangewithoutnotice.NolicenseisgrantedbyimplicationorotherwiseunderanypatentorpatentrightsofAnalogDevices.Trademarksandregisteredtrademarksarethepropertyoftheirrespectiveowners.Seethelastpagefordisclaimers.OneTechnologyWay,P.O.Box9106,Norwood,MA02062-9106,U.S.A.Tel:[phone]©2009–2010AnalogDevices,Inc.Allrightsreserved.FEATURESUltralowpower:aslowas23μAinmeasurementmodeand0.1μAinstandbymodeatVS=2.5V(typical)PowerconsumptionscalesautomaticallywithbandwidthUser-selectableresolutionFixed10-bitresolutionFullresolution,whereresolutionincreaseswithgrange,upto13-bitresolutionat±16g(maintaining4mg/LSBscalefactorinallgranges)Patentpending,embeddedmemorymanagementsystemwithFIFOtechnologyminimizeshostprocessorloadSingletap/doubletapdetectionActivity/inactivitymonitoringFree-falldetectionSupplyvoltagerange:2.0Vto3.6VI/Ovoltagerange:1.7VtoVSSPI(3-and4-wire)andI2CdigitalinterfacesFlexibleinterruptmodesmappabletoeitherinterruptpinMeasurementrangesselectableviaserialcommandBandwidthselectableviaserialcommandWidetemperaturerange(−40°Cto+85°C)10,000gshocksurvivalPbfree/RoHScompliantSmallandthin:3mm×5mm×1mmLGApackageAPPLICATIONSHandsetsMedicalinstrumentationGamingandpointingdevicesIndustrialinstrumentationPersonalnavigationdevicesHarddiskdrive(HDD)protectionGENERALDESCRIPTIONTheADXL345isasmall,thin,ultralowpower,3-axisaccelerometerwithhighresolution(13-bit)measurementatupto±16g.Digitaloutputdataisformattedas16-bittwoscomplementandisacces-siblethrougheitheraSPI(3-or4-wire)orI2Cdigitalinterface.TheADXL345iswellsuitedformobiledeviceapplications.Itmeasuresthestaticaccelerationofgravityintilt-sensingappli-cations,aswellasdynamicaccelerationresultingfrommotionorshock.Itshighresolution(3.9mg/LSB)enablesmeasurementofinclinationchangeslessthan1.0°.Severalspecialsensingfunctionsareprovided.Activityandinactivitysensingdetectthepresenceorlackofmotionbycomparingtheaccelerationonanyaxiswithuser-setthresholds.Tapsensingdetectssingleanddoubletapsinanydirection.Free-fallsensingdetectsifthedeviceisfalling.Thesefunctionscanbemappedindividuallytoeitheroftwointerruptoutputpins.Anintegrated,patentpendingmemorymanagementsystemwitha32-levelfirstin,firstout(FIFO)buffercanbeusedtostoredatatominimizehostprocessoractivityandloweroverallsystempowerconsumption.Lowpowermodesenableintelligentmotion-basedpowermanagementwiththresholdsensingandactiveaccelerationmeasurementatextremelylowpowerdissipation.TheADXL345issuppliedinasmall,thin,3mm×5mm×1mm,14-lead,plasticpackage.FUNCTIONALBLOCKDIAGRAM3-AXISSENSORSENSEELECTRONICSDIGITALFILTERADXL345POWERMANAGEMENTCONTROLANDINTERRUPTLOGICSERIALI/OINT1VSVDDI/OINT2SDA/SDI/SDIOSDO/ALTADDRESSSCL/SCLKGNDADC32LEVELFIFOCS07925-001Figure1.ADXL345Rev.B|Page2of40TABLEOFCONTENTSFeatures..............................................................................................1 Applications.......................................................................................1 GeneralDescription.........................................................................1 FunctionalBlockDiagram..............................................................1 RevisionHistory...............................................................................3 Specifications.....................................................................................4 AbsoluteMaximumRatings............................................................6 ThermalResistance......................................................................6 PackageInformation....................................................................6 ESDCaution..................................................................................6 PinConfigurationandFunctionDescriptions.............................7 TypicalPerformanceCharacteristics.............................................8 TheoryofOperation......................................................................13 PowerSequencing......................................................................13 PowerSavings.............................................................................14 SerialCommunications.................................................................15 SPI.................................................................................................15 I2C.................................................................................................18 Interrupts.....................................................................................20 FIFO.............................................................................................21 Self-Test.......................................................................................22 RegisterMap.....................