内容教程案例apds

APDS-9900andAPDS-9901

DigitalProximityandAmbientLigh sor

DataSheet

Description

TheAPDS-9900/9901providesdigitalambientlightsensing(ALS),IRLEDandacompleteproximitydetectionsysteminasingle8pinpackage.Theproximityfunctionoffersplugandpdetectionto100mm(withoutfrontglass)thuseliminatingtheneedforfactorycalibrationofequipmentorsub-assembly.Theproximitydetectionfeatureoperateswellfrombrightsunlighttodarkrooms.Thewidedynamicrangealsoallowsforoperationinshortdistancedetectionbehinddarkglasssuchasa.Inaddition,aninternalstatemachineprovidestheabilitytoputthedeviceintoalowpowermodeinbetweenALSandproximitymeasurementsprovidingverylowaveragepowerconsumption.TheALSprovidesaphotopicresponsetolightintensityinverylowlightconditionorbehinrkfacete.

TheAPDS-9900/9901isparticularlyusefulfordisymanagementwiththepurposeofextendingbatterylifeandprovidingoptimumviewingindiverselightingcon-ditions.Disypanelandkeyboardbacklightingcanaccountforupto30to40percentoftotaltformpower.TheALSfeaturesareidealforuseinnotebookPCs,LCDmonitors,flat-paneltvisions,andc.

Theproximityfunctionistargetedspecificallytowardsnearfieldproximityapplications.Inc,theproximitydetectioncandetectwhentheuserpositionsthephoneclosetotheirear.Thedeviceisfastenoughtoprovideproximityinformationatahighrepetitionrateneededwhenansweringaphonecall.Thisprovidesbothimproved“green”powersavingcapabilityandtheaddedsecuritytolockthecomputerwhentheuserisnotpresent.Theadditionofthemicro-opticslenseswithinthemodule,providehighlyefficienttransmissionandreceptionofinfraredenergywhichlowersoverallpowerdissipation.

OrderingInformation

Features

ALS,IRLEDandProximityDetectorinanOpticalModule

AmbientLigh sing(ALS)

ApproximatesHumanEyeResponse

Progr bleInterruptFunctionwithUpperandLowerThreshold

Upto16-BitResolution

HighSensitivityOperatesBehindDarkenedGlass

Upto1,000,000:1DynamicRange

ProximityDetection

FullyCalibratedto100mmDetection

IntegratedIRLEDandSynchronousLEDDriver

Eliminates“FactoryCalibration”ofProx

Coversa2000:1DynamicRange

Progr bleWaitTimer

WaitStatePower–70ATypical

Progr blefrom2.72msto>6Sec

I2CInterfaceCompatible

Upto400kHz(I2CFast-Mode)

DedicatedInterruptPin

SleepModePower-2.5ATypical

SmallPackageL3.94xW2.36xH1.35mm

Applications

BacklightDimming

Touch-screenDisable

Notebook/MonitorSecurity

AutomaticSpeakerphoneEnable

Automatic Pop-up

DigitalCameraEyeSensor

8-VDD 1-SDA

PartNumber

Packaging

ty

APDS-9900

Tape&Reel

5000perreel

APDS-9901

Tape&Reel

5000perreel

7-SCL

6-GND

5-LEDA

2-INT

3-LDR

4-LEDK

PAGE

10

FunctionalBlockDiagram

VDD

Interrupt

INT

ALSADC

Data

Ch0

SCL

Ch1

SDA

Data

LowerThreshold

ProxIRLED

LEDRegulatedConstantCurrentSink

ProxDetectADC

ControlLogic

UpperThreshold

LowerThreshold

UpperThreshold

I2CInterface

LEDA

LEDK

LDR

GND

DetailedDescription

TheAPDS-9900/9901light-to-digitaldeviceprovideson-chipCh0andCh1diodes,integratingamplifiers,ADCs,accumulators,clocks,buffers,comparators,astatemachineandanI2Cinterface.EachdevicecombinesoneCh0photodiode(visibleplusinfrared)andoneCh1infra-red-responding(IR)photodiode.TwointegratingADCssi-multaneouslyconverttheamplifiedphotodiodecurrentstoadigitalvalueprovidingupto16-bitsofresolution.Uponcompletionoftheconversioncycle,theconversionresultistransferredtotheCh0andCH1dataregisters.Thisdigitaloutputcanbereadbyamicroprocessorwheretheilluminance(ambientlightlevel)inLuxisderivedusinganempiricalformulatoapproximatethehumaneyeresponse.

Communicationtothedeviceisplishedthroughafast(upto400kHz),two-wireI2Cserialbusforeasycon-nectiontoamicrocontrollerorembeddedcontroller.ThedigitaloutputoftheAPDS-9900/9901deviceisinherent-lymoreimmunetonoisewhencomparedtoanoginterface.

TheAPDS-9900/9901providesaseparatepinforlevel-styleinterrupts.Wheninterruptsareenabledandapre-setvalueiceeded,theinterruptpinisassertedandremainsasserteduntilclearedbythecontrollingfirmware.

Theinterruptfeaturesimplifiesandimprovessystemefficiencybyeliminatingtheneedtopollasensorforalightintensityorproximityvalue.AninterruptisgeneratedwhenthevalueofSorproximityconversionexceedseitheranupperorlowerthreshold.Additionally,apro-grbleinterruptpersistencefeatureallowstheusertodeterminehowmanyconsecutiveexceededthresholdsarenecessarytotriggeraninterrupt.InterruptthresholdsandpersistencesettingsareconfiguredindependentlyforbothALSandproximity.

Proximitydetectionisfullyprovidedwithan850nmIRLED.AninternalLEDdriver(LDR)pin,isjumperconnectedtotheLEDcathode(LEDK)toprovideafactorycalibratedproximityof100+/-20mm.Thisisplishedwithaproprietarycurrentcalibrationtechniquethcountsforallvariancesinsilicon,optics,packageandmostimpor-tantlyIRLEDoutputpower.Thiswilleliminateorgreatlyreducetheneedforfactorycalibrationthatisrequiredformostdiscreteproximitysensorsolutions.WhiletheAPDS-9900/9901isfactorycalibratedatagivenpulsecount,thenumberofproximityLEDpulsescanbeprogrammedfrom1to255pulses,whichwillallowgreaterproximitydistancestobeachieved.Eachpulsehasa16speriod.

I/OPinsConfiguration

PIN

NAME

TYPE

DESCRIPTION

1

SDA

I/O

I2CserialdataI/Oterminal–serialdataI/OforI2C.

2

INT

O

Interrupt–opendrain.

3

LDR

I

LEDdriverforproximityemitter–upto100mA,opendrain.

4

LEDK

O

LEDCathode,connecttoLDRpininmostsystemstouseinternalLEDdrivercircuit

5

LEDA

I

LEDAnode,connecttoVBATToB

6

GND

Powersupplyground.AllvoltagesarereferencedtoGND.

7

SCL

I

I2Cserialclockinputterminal–clocksignalforI2Cserialdata.

8

VDD

PowerSupplyvoltage.

AbsoluteumRatingsoveroperating-airtemperaturerange(unlessotherwisenoted)†

Parameter

Symbol

Min

Max

Units TestConditions

PowerSupplyvoltage

VDD

3.8

V [1]

Digitalvoltagerange

-0.5

3.8

V

Digitaloutputcurrent

IO

-1

20

mA

Storagetemperaturerange

Tstg

-40

85

°C

†Stressesbeyondthoselistedunder“absoluteumratings”maycausepermanentdamagetothedevice.Thesearestressratingsonlyandfunctionaloperationofthedeviceattheseoranyotherconditionsbeyondthoseindicatedunder“mendedoperatingconditions”isnotimplied.Exposuretoabsolute-um-ratedconditionsforextendedperiodsmayaffectdevicereliability.

Note:

AllvoltagesarewithrespecttoGND.

mendedOperatingConditions

Parameter

Symbol

Min

Typ

Max

Units

OperatingAmbientTemperature

TA

-30

85

°C

Supplyvoltage

VDD

2.5

3.0

3.6

V

SupplyVoltageAccuracy,VDDtotalerrorincludingtransients

-3

+3

%

LEDSupplyVoltage

VBATT

2.5

4.5

V

AvailableOptions

PartNumber InterfaceDescriptionAPDS-9901 I2CVBUS=VDDInterfaceAPDS-9900 I2C1.8VVBUSInterface

OperatingCharacteristics,VDD=3V,TA=25°C(unlessotherwisenoted)

Parameter

Symbol

Min

Typ

Max

Units

TestConditions

Supplycurrent[1]

IDD

175

250

A

Active(ATIME=0xdb,100ms)

70

WaitMode

2.5

4.0

SleepMode

INTSDAoutputlowvoltage

VOL

0

0.4

V

3mAsinkcurrent

0

0.6

6mAsinkcurrent

Leakagecurrent,SDA,SCL,INTpins

ILEAK

-5

5

A

Leakagecurrent,LDRpin

ILEAK

10

A

SCL,SDAinputhighvoltage

VIH

0.7VBUS

1.25

V

APDS-9901APDS-9900

SCL,SDAinputlowvoltage,

VIL

0.3VBUS

0.54

V

APDS-9901APDS-9900

Oscillatorfrequency

fosc

705

750

795

kHz

PON=1

Note:

ThepowerconsumptionisraisedbytheprogrammedamountofProximityLEDDriveduringthe8ustheLEDpulseison.ThenominalandumvaluesareshownunderProximityCharacteristics.TheretheIDDsupplycurrentisIDDActive+ProximityLEDDriveprogrammedvalue.

ALSCharacteristics,VDD=3V,TA=25°C,Gain=16,AEN=1(unlessotherwisenoted)

Parameter

Channel

Min

Typ

Max

Units

TestConditions

DarkALSADCcountvalue

Ch0

0

1

5

counts

Ee=0,AGAIN=120x,ATIME=0xDB(100ms)

Ch1

0

1

5

ALSADCIntegrationTimeStepSize

2.58

2.72

2.90

ms

ATIME=0xff

ALSADCNumberofIntegrationSteps

1

256

steps

FullScaleADCCountsperStep

1023

counts

FullscaleADCcountvalue

65535

counts

ATIME=0xC0

ALSADCcountvalue

Ch0

4000

5000

6000

counts

p=640nm,Ee=56W/cm2,

Ch1

790

ATIME=0xF6(27ms),GAIN=16x

Ch0

4000

5000

6000

p=850nm,Ee=79W/cm2,

Ch1

2800

ATIME=0xF6(27ms),GAIN=16x

ALSADCcountvalueratio:

10.8

15.8

20.8

%

p=640nm,ATIME=0xF6(27ms)

Ch1/Ch0

41

56

68

p=850nm,ATIME=0xF6(27ms)

IrradianceResponsivity:

Ch0

29.1

Countsper

p=640nm,ATIME=0xF6(27ms)

Re

Ch1

4.6

(W/cm2)

Ch0

22.8

p=850nm,ATIME=0xF6(27ms)

Ch1

12.7

Gainscaling,relativeto

-5

5

%

8x

1xgainsetting

-5

5

16x

-5

5

120x

Notes:

Opticalmeasurementsaremadeusingsmall-angleradiationfromlight-emittingdiodeopticalsources.Visible640nmLEDsandinfrared850nmLEDsareusedforfinalproducttestingforcompatibilitywithhigh-volumeproduction.

The640nmirradianceEeisdbyInGaPlight-emittingdiodewiththefollowingcharacteristics:peakwavelength=640nmandspectralhalfwidth½=17nm.

The850nmirradianceEeisdbyaGaAslight-emittingdiodewiththefollowingcharacteristics:peakwavelength=850nmandspectralhalfwidth½=40nm.

Thespecifiedlightintensityis100%modulatedbythepulseoutputofthedevicesothatduringthepulseoutputlowtime,thelightintensityisatthespecifiedlevel,andzerootherwise.

ProximityCharacteristics,VDD=3V,TA=25°C,PGAIN=1,PEN=1(unlessotherwisenoted)

Parameter

Min

Typ

Max

Units

TestConditions

IDDSupplycurrent–LDRPulseOn

3

mA

ADCConversionTimeStepSize

2.72

ms

PTIME=0xff

ADCNumberofIntegrationSteps

1

steps

PTIME=0xff

FullScaleADCCounts

1023

counts

PTIME=0xff

ProximityIRLEDPulseCount

0

255

pulses

ProximityPulsePeriod

16.3

s

ProximityPulse–LEDOnTime

7.2

s

ProximityLEDDrive

100

mA

PDRIVE=0

ISINKSinkcurrent@600mV,

50

PDRIVE=1

LDRPin

25

PDRIVE=2

12.5

PDRIVE=3

ProximityADCcountvalue,noobject

100

LEDdriving8pulses,PDRIVE=0,openview(noglass)andnoreflectiveobjectabovethemodule.

ProximityADCcountvalue,100mmdistanceobject

416

520

624

counts

Reflectingobject–73mmx83mmKodak90%greycard,100mmdistance,LEDdriving8pulses,PDRIVE=0,openview(noglass)abovethemodule.

IRLEDCharacteristics,VDD=3V,TA=25C

Parameter

Min

Typ

Max

Units

TestConditions

ForwardVoltage,VF

1.4

1.5

V

IF=20mA

ReverseVoltage,VR

5.0

V

IR=10A

RadiantPower,PO

4.5

mW

IF=20mA

PeakWavelength,P

850

nm

IF=20mA

SpectrumWidth,HalfPower,

40

nm

IF=20mA

OpticalRiseTime,TR

20

ns

IFP=100mA

OpticalFallTime,TF

20

ns

IFP=100mA

WaitCharacteristics,VDD=3V,TA=25°C,Gain=16,WEN=1(unlessotherwisenoted)

Parameter

Min

Typ

Max

Units

TestConditions

WaitStepSize

2.72

ms

WTIME=0xff

WaitNumberofStep

1

256

steps

CharacteristicsoftheSDAandSCLbuslines,VDD=3V,TA=25°C(unlessotherwisenoted)†

STANDARD-MODE FAST-MODE

Parameter Symbol

Min.

Max.

Min.

Max.

Units

SCLclockfrequency fSCL

0

100

0

400

kHz

Holdtime(repeated)STARTcondition. tHD;STAAfterthisperiod,thefirstclockpulseisgenerated

4.0

–

0.6

–

s

LOWperiodoftheSCLclock tLOW

4.7

–

1.3

–

s

HIGHperiodoftheSCLclock tHIGH

4.0

–

0.6

–

s

Set-uptimeforarepeatedSTARTcondition tSU;STA

4.7

–

0.6

–

s

Dataholdtime tHD;DAT

0

–

0

–

ns

Dataset-uptime tSU;DAT

250

–

100

–

ns

RisetimeofbothSDAandSCLsignals tr

20

1000

20

300

ns

FalltimeofbothSDAandSCLsignals tf

20

300

20

300

ns

Set-uptimeforSTOPcondition tSU;STO

4.0

–

0.6

–

s

Bus timebetweenaSTOPandSTARTcondition tBUF

4.7

–

1.3

–

s

Capacitiveloadforeachbusline Cb

–

400

–

400

pF

NoisemarginattheLOWlevelforeachconnected VnLdevice(includinghysteresis)

0.1VBUS

–

0.1VBUS

–

V

NoisemarginattheHIGHlevelforeachconnected VnHdevice(includinghysteresis)

02VBUS

–

02VBUS

–

V

†Specifiedbydesignandcharacterization;notproductiontested.

tf

tLOW

tr

tSU;DAT

tf

tHD;STA

tSP

tr

tBUF

S

tHD;STA

tHD;DAT

t

tSU;STA

tSU;STO

HIGH

Sr

P

S

SDA

SCL

MSC610

SCL

SDA

Figure1.I2CBusTimingDiagram

Ch0

Ch1

1.2

NORMALIZEDRESPONSITIVITY

1.0

0.8

0.6

0.4

0.2

0.0

300

400 500 600 700 800 900 1000 1100

WAVELENGTH(nm)

9000

8000

7000

AvgSensorLUX

6000

5000

4000

3000

2000

1000

00 10002000300040005000600070008000

MeterLUX

Figure2.SpectralResponse Figure3a.ALSSensorLUXvs.MeterLUXusingFluorescentLight

0.1

0.08

AvgSensorLUX

AvgSensorLUX

0.06

0.04

MeterLUX

Figure3b.ALSSensorLUXvs.MeterLUXusingIncandescentLight

1.1

1500

0.02

00 0.010.020.030.040.050.060.070.080.090.1

MeterLUX

Figure3c.ALSSensorLUXvs.MeterLUXusingLowLuxFluorescentLight

1.2

NORMALIZEDIDD@3V

1.1

NORMALIZEDIDD@3V25°C

1.0

1.0

0.9

0.9

0.8

2.4 2.6 2.8 3 3.2 3.4 3.6 3.8

VDD(V)

0.8

-60 -40 -20 0 20 40 60 80 100

TEMPERATURE(°C)

Figure4a.NormalizedIDDvs.VDD Figure4b.NormalizedIDDvs.Temperature

1.1

1.0

NORMALIZEDRESPONSITIVITY

0.9

0.8

0.7

0.6

0.5

0.4

0.3

0.2

0.1

0.0

-100 -80 -60 -40 -20 0 20 40 60 80 100

ANGLE(DEG)

Figure5.NormalizedALSResponsevs.AngularDiscement

PRINCIPLESOFOPERATION

SystemStateMachine

TheAPDS-9900/9901providescontrolofALS,proximitydetectionandpowermanagementfunctionalitythroughaninternalstatemachine.Afpower-on-reset,thedeviceisinthesleepmode.AssoonasthePONbitisset,thedevicewillmovetothestartstate.ItwillthencontinuethroughtheProx,WaitandALSstates.Ifthesestatesareenabled,thedevicewillexecuteeachfunction.IfthePONbitissettoa0,thestatemachinewillcontinueuntilallconversionsarecompletedandthengointoalowpowersleepmode.

Sleep

PON=1(rO:b0)

PON=0(rO:b0)

Start

Prox

ALS

Wait

Figure6.SimplifiedStateDiagram

NOTE:Inthis,thenomenclatureusesthebitfieldnameinitalicsfollowedbytheregisternumberandbitnumbertoallowtheusertoeasilyidentifytheregisterandbitthatcontrolsthefunction.Forexample,thepoweron(PON)isinregister0,bit0.ThisisrepresentedasPON(r0:b0).

Ch0andCh1Diodes

Conventionalsilicondetectorsrespondstronglytoinfraredlight,whichthehumaneyedoesnotsee.Thiscanleadtosignificanterrorwhentheinfraredcontentoftheambientlightishigh(suchaswithincandescentlighting)duetothedifferencebetweenthesilicondetectorresponseandthebrightnessperceivedbythehumaneye.

Thisproblemis eintheAPDS-9900/9901throughtheuseoftwophotodiodes.Oneofthephotodiodes,referredtoastheCh0channel,issensitivetobothvisibleandinfraredlightwhilethesecondphotodiodeissensitiveprimarilytoinfraredlight.TwointegratingADCsconvertthephotodiodecurrentstodigitaloutputs.TheCH1DATAdigitalvalueisusedtocompensatefortheeffectoftheinfraredcomponentoflightontheCH0DATAdigitalvalue.TheADCdigitaloutputsfromthetwochannelsareusedinaformulatoobtainavaluethatapproximatesthehumaneyeresponseinunitsofLux.

ALSOperation

TheALSenginecontainsALSgaincontrol(AGAIN)andtwointegratingog-to-digitalconverters(ADC)fortheCh0andCh1photodiodes.TheALSintegrationtime(ALSIT)impactsboththeresolutionandthesensitivityoftheALSreading.Integrationofbothchannelsoccurssimultaneouslyanduponcompletionoftheconversioncycle,theresultsaretransferredtotheCh0andCH1dataregisters(CDATAxandIRDATAx).Thisdataisalsoreferredtoaschannel“count”.Thetransfersaredouble-bufferedtoensurethatinvaliddataisnotreadduringthetransfer.Afterthetransfer,thedeviceautomaticallymovestothenextstateinaccordancewiththeconfiguredstatemachine.

Ch0

Ch1Data

Ch1ADC

ALSControl

Ch0Data

Ch0ADC

Ch1

CDATAH(r0x15),CDATAL(r0x14)

ATIME(r0x01),0xffto0x00

AGAIN(r0xOF,b1:0),1x,8x,16x,120xGainIRDATAH(r0x17),IRDATAL(r0x16)

Figure7.ALSOperation

TheALSTimingregistervalue(ATIME)forprogrammingtheintegrationtime(ALSIT)isa2’scomplementvalues.TheALSTimingregistervaluecanbecalculatedasfollows:

ATIME=256–ALSIT/2.72ms

Inversely,theintegrationtimecanbecalculatedfromtheregistervalueasfollows:ALSIT=2.72ms*(256–ATIME)

Forexample,ifa100msintegrationtimeisneeded,thedeviceneedstobeprogrammedto:ATIME=256–(100/2.72)=256–37=219=0xDB

Conversely,theprogrammedvalueof0xC0wouldcorrespondto:ALSIT=(256–0xC0)*2.72=64*2.72=172ms.

Note:2.72mscanbeestimatedas87/32.Multiplyby87theshiftby5bits.

CalculatingALSLux

Definition:

CH0DATA=256*CDATAH(r0x15)+CDATAL(r0x14)CH1DATA=256*IRDATAH(r0x17)+IRDATAL(r0x16)

IAC=IRAdjustedCountLPC=LuxperCount

ALSIT=ALSIntegrationTime(ms)AGAIN=ALSGain

DF=DeviceFactor,DF=52forAPDS-9900/9901GA=Glass(orLens)AttenuationFactor

B,C,D–Coefficients

LuxEquation:

IAC1=CH0DATA–BxCH1DATAIAC2=CxCH0DATA–DxCH1DATAIAC=Max(IAC1,IAC2,0)

LPC=GAxDF/(ALSIT×AGAIN)Lux=IACxLPC

Coefficientsinopenair:GA=0.48

B=2.23

C=0.7

D=1.42

SampleLuxCalculationinOpenAir

Assumethefollowingconstants:ALSIT=400

AGAIN=1

LPC=GAxDF/(ALSIT×AGAIN)LPC=0.48x52/(400x1)

LPC=0.06

Assumethefollowingmeasurements:CH0DATA=5000

CH1DATA=525

Then:

IAC1=5000–2.23x525=3829

IAC2=0.7x5000–1.42x525=2755

IAC=Max(3829,2755,0)=3829

Lux:

Lux=IACXLPCLux=3829X0.06

Lux=230

Note:pleaserefertoapplicationnoteforcoefficientGA,B,CandDcalculationwithwindow.

10000

1000

100

LUX

10

1

0.1

mendALSOperations

ProximityDetection

ProximitysensingusesaninternalIRLEDlightsourcetoemitlightwhichisthenviewedbytheintegratedlightdetectortomeasuretheamountofreflectedlightwhenanobjectisinthelightpath.Theamountoflightdetectedfromareflectedsurfacecanthenbeusedtodetermineanobject’sproximitytothesensor.TheAPDS-9900/9901isfactorycalibratedtomeettherequirementofproximitysensingof100+/-20mm,thuseliminatingtheneedforfactorycalibrationofequipment.WhentheAPDS-9900/9901iscedbehindatypicalglasssurface,theproximitydetectionachievedisaround25to40mm,thusprovidinganidealtouch-screendisable.

0.011 10 100 1000 10000 100000

Counts

Figure8.GainandIntegrationTimetoLuxwithoutIR

Withtheprogrammingversatilityoftheintegrationtimeandgain,itcanbedifficulttounderstandwhentousethedifferentmodes.Figure8showsalog-logplotoftheLuxvs.integrationtimeandgainwithaspectralfactorofunityandnoIRpresent.

Theumilluminancewhichcanbemeasuredis

~10kLuxwithnoIRpresent.Theinterceptwithacountof1showstheresolutionofeachsetting.TheLuxvaluesinthetableincreaseastheSFincreases(spectralattenu-ationincreases).Forexample,ifa10%transmissiveglassisused,theLuxvalueswouldallbemultipliedby10.TheLuxvaluesinthetabledecreaseastheIRFactordecreases.Forexample,witha10%IRFactor,whichcorrespondstoastrongincandescentlight,theLuxvaluewouldneedtobedividedby10.

Therearemanyfactorsthatwillimpactthedecisiononwhichvaluetouseforintegrationtimeandgain.Oneofthefirstfactorsis50/60Hzripplerejectionforfluorescentlighting.Theprogrammedvalueneedstobemultiplesof10/8.3msorthehalfcycletime.Bothfrequenciescanberejectedwithaprogrammedvalueof50ms(ATIME=0xED).Withthisvalue,theresolutionwillbe1.3Luxpercount.Ifhigherresolutionisneeded,alongerintegrationtimemaybeneeded.Inthiscase,theintegrationtimeshouldbeprogrammedinmultiplesof50.

Thelightlevelisthenextdeterminingfactorforconfig-uringdevicesettings.Underbrightconditions,thecountwillbefairlyhigh.Ifalowlightmeasurementisneeded,ahighergainand/orlongerintegrationtimewillbeneeded.Asageneralrule,itismendedtohaveaCh0channelcountofatleast10toaccurayapplytheLuxequation.

Thedigitalaccumulationislimitedto16bits,whichoccursatanintegrationtimeof173ms.Thisistheummendedprogrammedintegrationtimebeforeincreasingthegain.(150msisthe umtoreducethe

fluorescentripple.)

TheAPDS-9900/9901hascontrolsforthenumberofIRpulses(PPCOUNT),theintegrationtime(PTIME),theLEDdrivecurrent(PDRIVE)andthephotodiodeconfiguration(PDIODE).Atoftheintegrationcycle,theresultsarelatchedintotheproximitydata(PDATA)register.

TheLEDdrivecurrentiscontrolledbyaregulatedcurrentsinkontheLDRpin.ThisfeatureeliminatestheneedtouseacurrentlimitingresistortocontrolLEDcurrent.TheLEDdrivecurrentcanbeconfiguredfor12.5mA,25mA,50mA,or100mA.ForhigherLEDdriverequirements,anexternalPtypetransistorcanbeusedtocontroltheLEDcurrent.

ThenumberofLEDpulsescanbeprogrammedtoavalueof1to255pulsesasneeded.IncreasingthenumberofLEDpulsesatagivencurrentwillincreasethesensorsen-sitivity.Sensitivitygrowsbythesquarerootofthenumberofpulses.Eachpulsehasa16Speriod.

AddIR+ SubtractBackground Background

LEDOn LEDOff

16s

Theproximityintegrationtime(PTIME)istheperiodoftimethattheinternalADCconvertstheogsignaltoadigitalcount.ItismendthatthisbesettoaminimumofPTIME=0xFFor2.72ms.

IRLEDPulses

Figure9.ProximityIRLEDWaveform

OpticalDesignConsiderations

TheAPDS-9900/9901simplifiestheopticalsystemdesignbyeliminatingtheneedforlightpipesandimprovessystemopticalefficiencybyprovidingaperturesandpackageshieldingwhichwillreducecrosstalkwhencedinthefinalsystem.ByreducingtheIRLEDtoglasssurfacecrosstalk,proximityperformanceisgreatlyimprovedandenablesawiderangeofapplicationsutilizingtheAPDS-9900/9901.Themodulepackagedesignhasbeenoptimizedforminimumpackagefootprintandshortdistanceproximityof100mmtypical.Thespacingbetweentheglasssurfaceandpackagetopsurfaceiscriticaltocontrollingthecrosstalk.Ifthepackagetotopsurfacespacinggap,windowthicknessandtransmittancearemet,thereshouldbenoneedtoaddadditionalcom-ponents(suchasabarrier)betweentheLEDandphoto-diode.Thuswithsomesimplemechanicaldesignimple-mentations,theAPDS-9900/9901willperformwellintheendequipmentsystem.

APDS-9900/9901ModuleOptimizeddesignparameters

Windowthickness,t≤1.0mm

Airgap,g≤0.5mm

AssumingwindowIRtransmittance90%

TheAPDS-9900/9901isavailableinalowprofilepackagethatcontainsopticswhichprovidesopticalgainonbothttheLEDandthesensorsideofthepackage.ThedevicehasapackageZheightof1.35mmandwillsupportairgapof<=0.5mmbetweentheglassandthepackage.Theassumptionoftheopticalsystemleveldesignisthatglasssurfaceabovethemoduleis<=to1.0mm.

Byintegratingthemicro-opticsinthepackage,theIRenergyemittedcanbereducedthusconservingthepreciousbatterylifeintheapplication.

ThesystemdesignerhastheabilitytooptimizetheirdesignsforslimformfactorZheightaswellasimprovetheproximitysensing,savebatterypoweranddisablethetouchscreeninacellularphone.

stic/GlassWindow

AirGap,g

APDS-9900/9901

WindowsThickness,t

Figure10.ProximityDetection

6P(100mA)

8P(100mA)

4P(100mA)

16P(100mA)

8P(50mA)

1200

1000

800

1200

4P(100mA)

6P(100mA)

8P(100mA)

16P(100mA)

8P(50mA)

1000

800

PSCOUNT

PSCOUNT

600 600

400

200

0

0 2 4 6 8 10 12

DISTANCE(cm)

0 2 4 6 8 10 12 14 16

DISTANCE(cm)

18 20

Figure11a.PSOutputvs.Distance,atVariousPulsenumber(LEDdriveCurrent).Noglassinfrontofthemodule,18%KodakGreyCard.

Figure11b.PSOutputvs.Distance,atVariousPulsenumber(LEDdriveCurrent).Noglassinfrontofthemodule,90%KodakGreyCard.

Interrupts

TheinterruptfeatureoftheAPDS-9900/9901simplifiesandimprovessystemefficiencybyeliminatingtheneedtopollthesensorforalightintensityorproximityvalue.TheinterruptmodeisdeterminedbythePIENorAIENfieldintheENABLEregister.

TheAPDS-9900/9901implementsfour16-bit-wideinterruptthresholdregistersthatallowtheusertodefinethresholdsaboveandbelowadesiredlightlevel.ForALS,aninterruptcanbegeneratedwhentheALSCh0data(CDATA)exceedstheupperthresholdvalue(AIHTx)orfallsbelowthelowerthreshold(AILTx).Forproximity,

aninterruptcanbegeneratedwhentheproximitydata(PDATA)exceedstheupperthresholdvalue(PIHTx)orfallsbelowthelowerthreshold(PILTx).

Tofurthercontrolwhenaninterruptoccurs,theAPDS-9900/9901providesaninterruptpersistencefeature.ThisfeatureallowstheusertospecifyanumberofconversioncyclesforwhichaneventexceedingtheALSinterruptthresholdmustpersist(APERS)ortheproximityinterruptthresholdmustpersist(PPERS)beforeactuallygeneratinganinterrupt.Refertotheregisterdescriptionsfordetailsonthelengthofthepersistence.

PILTH(r09),PIHTL(r08)

AIHTH(r07),AIHTL(r06)

Ch0

Ch1

AILTH(r05),AILTL(r04)

LowerLimit

ALSPersistence

UpperLimit

LowerLimit

Ch1Data

Ch1ADC

Ch0Data

Ch0ADC

ProxPersistence

UpperLimit

ProxData

ProxADC

ProxIntegration

PIHTH(r0xOB),PIHTL(r0xOA) PPERS(r0xOC,b7:4)

APERS(r0xOC,b3:0)

Figure12.Progr bleInterrupt

StateDiagram

Thefollowingshowsamoredetailedflowforthestatemachine.Thedevicestartsinthesleepmode.ThePONbitiswrittentoenablethedevice.IfthePENbitisset,thestatemachinewillstepthroughtheproximitystatesofproximityaccumulateandthenproximityADCcon-version.Assoonastheconversioniscomplete,thestatemachinewillmovetothefollowingstate.

IftheWENbitisset,thestatemachinewillthencyclethroughthewaitstate.IftheWLONGbitisset,thewaitcyclesareextendedby12xovernormaloperation.Whenthewaitcounterterminates,thestatemachinewillsteptothe