ICS‐41350
BottomPortPDMLow‐PowerMulti‐Mode
MicrophoneWithHighAOPMode
InvenSensereservestherighttochangethedetail
specificationsasmayberequiredtopermit
improvementsinthedesignofitsproducts.
InvenSenseInc.
1745TechnologyDrive,SanJose,CA95110U.S.A
+1(408)988–7339
www.invensense.com
DocumentNumber:DS‐000047
Revision:1.1
RevDate:06/23/2016
GENERALDESCRIPTION
TheICS‐41350isalow‐power,low‐noisedigitalMEMS
microphoneinasmallpackage.TheICS‐41350consistsofa
MEMSmicrophoneelementandanimpedanceconverter
amplifierfollowedbyafourth‐orderΣ‐Δmodulator.Thepulse
densitymodulated(PDM)interfaceallowstwomicrophones
tobetimemultiplexedonadatalineusingasingleclock.
TheICS‐41350hasmultiplemodesofoperation:High
Performance,LowPower(AlwaysOn),StandardandSleep.
TheICS‐41350haslowpowerandhighSNRinalloperational
modes.Ithas126dBSPLAOPinHighPerformancemode,and
120dBSPLAOPinStandardandLow‐Powermodes.
TheICS‐41350supportsultrasoundapplicationsinHigh
PerformanceMode.Ithasanextendedultrasonicresponseupto
40kHzwithhighSNR.
TheICS‐41350isavailableinasmall3.5×2.65×0.98mm
surface‐mountpackage.Itisreflowsoldercompatiblewith
nosensitivitydegradation.
APPLICATIONS
Smartphones
MicrophoneArrays
Tablets
Cameras
BluetoothHeadsets
NotebookPCs
SecurityandSurveillance
FEATURES
SPECLOW‐POWER
MODE
STANDARD
MODE
HIGH
PERFORMANCE
MODE
Sensitivity−26dBFS±1dB−26dBFS±1dB−32dBFS±1dB
SNR63dBA64dBA64dBA
Current185µA430µA650µA
AOP120dBSPL120dBSPL126dBSPL
Clock400
–
800kHz1.0
–
3.3MHz4.1
–
4.8MHz
3.5×2.65×0.98mmsurface‐mountpackage
Lowpower:185µAinLow‐PowerMode
Extendedfrequencyresponsefrom50Hzto>20kHz
Ultrasoundsupportupto40kHz
SleepMode:12µA
Highpowersupplyrejection(PSR):−97dBFS
Fourth‐orderΣ‐Δmodulator
Digitalpulsedensitymodulation(PDM)output
CompatiblewithSn/PbandPb‐freesolderprocesses
RoHS/WEEEcompliant
FUNCTIONALBLOCKDIAGRAM
ORDERINGINFORMATION
PARTTEMPRANGEPACKAGING
ICS‐41350−40°Cto+85°C13”TapeandReel
EV_ICS‐41350‐FX—

ICS‐41350
ADC
POWER
MANAGEMENT
CLK
DAT
A
VDD
GND
PDM
MODULATOR
CHANNEL
SELECT
SELECT
ICS‐41350
DocumentNumber:DS‐000047
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TABLEOFCONTENTS
GeneralDescription.....................................................................................................................................................................1
Applications.................................................................................................................................................................................1
Features.......................................................................................................................................................................................1
FunctionalBlockDiagram............................................................................................................................................................1
OrderingInformation...................................................................................................................................................................1
TableofContents....................................................................................................................................................................................2
Specifications..........................................................................................................................................................................................4
Table1.Acoustical/ElectricalCharacteristics–General..............................................................................................................4
Table2.Acoustical/ElectricalCharacteristics–High‐PerformanceMode...................................................................................4
Table3.Acoustical/ElectricalCharacteristics–StandardMode..................................................................................................5
Table4.Acoustical/ElectricalCharacteristics–Low‐PowerMode..............................................................................................5
Table5.DigitalInput/OutputCharacteristics..............................................................................................................................6
Table6.PDMDigitalInput/Output..............................................................................................................................................6
TimingDiagram............................................................................................................................................................................7
AbsoluteMaximumRatings....................................................................................................................................................................8
Table7.AbsoluteMaximumRatings...........................................................................................................................................8
ESDCaution.................................................................................................................................................................................8
SolderingProfile...........................................................................................................................................................................9
Table8.RecommendedSolderingProfile*..................................................................................................................................9
PinConfigurationsAndFunctionDescriptions.....................................................................................................................................10
Table9.PinFunctionDescriptions.............................................................................................................................................10
TypicalPerformanceCharacteristics.....................................................................................................................................................11
TheoryOfOperation.............................................................................................................................................................................12
PDMDataFormat......................................................................................................................................................................12
Table10.ICS‐41350ChannelSetting.........................................................................................................................................12
PDMMicrophoneSensitivity.....................................................................................................................................................12
ApplicationsInformation......................................................................................................................................................................14
LowPowerMode.......................................................................................................................................................................14
DynamicRangeConsiderations.................................................................................................................................................14
ConnectingPDMMicrophones..................................................................................................................................................14
UltrasoundApplications............................................................................................................................................................16
SleepMode................................................................................................................................................................................16
Start‐UpTime.............................................................................................................................................................................16
SupportingDocuments.........................................................................................................................................................................17
ApplicationNotes......................................................................................................................................................................17
PCBDesignAndLandPatternLayout...................................................................................................................................................18
PCBMaterialAndThickness......................................................................................................................................................18
HandlingInstructions............................................................................................................................................................................19
ICS‐41350
DocumentNumber:DS‐000047
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PickAndPlaceEquipment.........................................................................................................................................................19
ReflowSolder.............................................................................................................................................................................19
BoardWash...............................................................................................................................................................................19
OutlineDimensions...............................................................................................................................................................................20
OrderingGuide..........................................................................................................................................................................20
RevisionHistory.........................................................................................................................................................................21
ComplianceDeclarationDisclaimer......................................................................................................................................................22
ICS‐41350
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SPECIFICATIONS
TABLE1.ACOUSTICAL/ELECTRICALCHARACTERISTICS–GENERAL
T
A
=25°C,VDD=1.8to3.3V,SCK=2.4MHz,50×decimation,C
LOAD
=30pFunlessotherwisenoted.Typicalspecificationsarenot
guaranteed.
PARAMETER CONDITIONSMINTYPMAXUNITSNOTES
PERFORMANCE
DirectionalityOmni
OutputPolarityInputacousticpressurevs.
outputdataNon‐Inverted
SupplyVoltage(V
DD
) 1.653.63V
SleepModeCurrent(I
S
)SCK<200kHz1220µA
TABLE2.ACOUSTICAL/ELECTRICALCHARACTERISTICS–HIGH‐PERFORMANCEMODE
T
A
=25°C,VDD=1.8to3.3V,SCK=4.8MHz,50×decimation,C
LOAD
=30pFunlessotherwisenoted.Typicalspecificationsarenot
guaranteed.
PARAMETER CONDITIONSMINTYPMAXUNITSNOTES
Sensitivity1kHz,94dBSPL−33−32−31dBFS1,2
Signal‐to‐NoiseRatio(SNR)20kHzbandwidth,A‐weighted 64dBA
EquivalentInputNoise(EIN)20kHzbandwidth,A‐weighted 30dBASPL
DynamicRangeDerivedfromEINandAOP96dB
Lowfrequency−3dBpoint 50 Hz3
UltrasoundBandwidth 40kHz
TotalHarmonicDistortion(THD)105dBSPL 0.21%
PowerSupplyRejection(PSR)217Hz,100mVp‐psquarewave
superimposedonVDD=1.8V,A‐
weighted
−97dBFS
PowerSupplyRejection—Swept
Sine
1kHzsinewave−100dBFS
AcousticOverloadPoint10%THD126dBSPL
Full‐ScaleAcousticLevel0dBFSoutput126dBSPL
SupplyCurrent(I
S
)V
DD
=1.8V,noload650750µA
Note1:SensitivityisrelativetotheRMSlevelofasinewavewithpositiveamplitudeequalto100%1sdensityandnegativeamplitudeequalto0%1sdensity.
Note2:Thesensitivityshallnotdeviatemorethan1.0dBfromitsinitialvalueafterreliabilitytests.
Note3:SeeFigure4.

ICS‐41350
DocumentNumber:DS‐000047
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TABLE3.ACOUSTICAL/ELECTRICALCHARACTERISTICS–STANDARDMODE
T
A
=25°C,VDD=1.8to3.3V,SCK=2.4MHz,50×decimation,C
LOAD
=30pFunlessotherwisenoted.Typicalspecificationsarenot
guaranteed.
PARAMETER CONDITIONSMINTYPMAXUNITSNOTES
Sensitivity1kHz,94dBSPL−27−26−25dBFS1,2
Signal‐to‐NoiseRatio(SNR)20kHzbandwidth,A‐weighted 64dBA
EquivalentInputNoise(EIN)20kHzbandwidth,A‐weighted 30dBASPL
DynamicRangeDerivedfromEINandAOP 90dB
Lowfrequency−3dBpoint50 Hz3
TotalHarmonicDistortion(THD)105dBSPL 0.21%
PowerSupplyRejection(PSR)217Hz,100mVp‐psquarewave
superimposedonVDD=1.8V,A‐
weighted
−97dBFS
PowerSupplyRejection—Swept
Sine
1kHzsinewave−104dBFS
AcousticOverloadPoint10%THD120dBSPL
Full‐ScaleAcousticLevel0dBFSoutput120dBSPL
SupplyCurrent(I
S
)V
DD
=1.8V,noload430500µA
Note1:SensitivityisrelativetotheRMSlevelofasinewavewithpositiveamplitudeequalto100%1sdensityandnegativeamplitudeequalto0%1sdensity.
Note2:Thesensitivityshallnotdeviatemorethan1.0dBfromitsinitialvalueafterreliabilitytests.
Note3:SeeSeeFigure4.
TABLE4.ACOUSTICAL/ELECTRICALCHARACTERISTICS–LOW‐POWERMODE
T
A
=25°C,VDD=1.8to3.3V,SCK=768kHz,50×decimation,C
LOAD
=30pFunlessotherwisenoted.Typicalspecificationsarenot
guaranteed.
PARAMETER CONDITIONSMINTYPMAXUNITSNOTES
Sensitivity1kHz,94dBSPL−27−26−25dBFS1,2
Signal‐to‐NoiseRatio(SNR)8kHzbandwidth,A‐weighted 63dBA
EquivalentInputNoise(EIN)8kHzbandwidth,A‐weighted 31dBASPL
DynamicRangeDerivedfromEINandAOP89dB
Lowfrequency−3dBpoint50 Hz3
TotalHarmonicDistortion(THD)105dBSPL 0.21%
PowerSupplyRejection(PSR)217Hz,100mVp‐psquarewave
superimposedonVDD=1.8V,A‐
weighted
−97dBFS
PowerSupplyRejection—Swept
Sine
1kHzsinewave−98dBFS
AcousticOverloadPoint10%THD120dBSPL
Full‐ScaleAcousticLevel0dBFSoutput120dBSPL
SupplyCurrent(I
S
)V
DD
=1.8V,noload185225µA
Note1:SensitivityisrelativetotheRMSlevelofasinewavewithpositiveamplitudeequalto100%1sdensityandnegativeamplitudeequalto0%1sdensity.
Note2:Thesensitivityshallnotdeviatemorethan1.0dBfromitsinitialvalueafterreliabilitytests.
Note3:SeeFigure4.

ICS‐41350
DocumentNumber:DS‐000047
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Revision:1.1
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TABLE5.DIGITALINPUT/OUTPUTCHARACTERISTICS
T
A
=25°C,1.8V<VDD<3.3V,unlessotherwisenoted.
PARAMETER CONDITIONSMINTYPMAXUNITSNOTES
InputVoltageHigh(V
IH
) 0.65xV
DD
 V
InputVoltageLow(V
IL
) 0.35xV
DD
V
OutputVoltageHigh(V
OH
)I
LOAD
=0.5mA0.7xV
DD
V
DD
 V
OutputVoltageLow(V
OL
)I
LOAD
=0.5mA00.3xV
DD
V
OutputDCOffsetPercentoffullscale3%
Latency <30µs
TABLE6.PDMDIGITALINPUT/OUTPUT
T
A
=25°C,1.8V<VDD<3.3V,unlessotherwisenoted.
PARAMETERCONDITIONSMINTYPMAXUNITSNOTES
MODESWITCHING
SleepTimeTimefromf
CLK
falling<200kHz1ms
Wake‐UpTimeHigh‐Performance&Standardmodes,
SleepModetof
CLK
>1MHz,output
within0.5dBoffinalsensitivity,power
on
20ms
Wake‐UpTimeLow‐PowerMode,SleepModetof
CLK
>400kHz,outputwithin0.5dBoffinal
sensitivity,poweron
20ms
SwitchingtimeBetweenLow‐PowerandStandard
Modes10ms
SwitchingtimeBetweenLow‐PowerandHigh‐
PerformanceModes10ms
INPUT
t
CLKIN
Inputclockperiod2082500ns
ClockFrequency(CLK)
SleepMode200kHz
Low‐PowerMode400 800kHz
StandardMode1.0 3.3MHz
High‐PerformanceMode4.1 4.8MHz
ClockDutyCyclef
CLK
<3.3MHz40 60%
f
CLK
>4.1MHz48 52%
t
RISE
CLKrisetime(10%to90%level)25ns1
t
FALL
CLKfalltime(90%to10%level)25ns1
OUTPUT
t
1OUTEN
DATA1(right)drivenafterfallingclock
edge
50ns
t
1OUTDIS
DATA1(right)disabledafterrising
clockedge
540ns
t
2OUTEN
DATA2(left)drivenafterrisingclock
edge
50ns
t
2OUTDIS
DATA2(left)disabledafterfallingclock
edge
540ns
Note1:Guaranteedbydesign
ICS‐41350
DocumentNumber:DS‐000047
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Revision:1.1
RevDate:06/23/2016
TIMINGDIAGRAM
Figure1.PulseDensityModulatedOutputTiming
t
CLKIN
CLK
DATA2
DATA1
t
2OUTDIS
t
1OUTDIS
t
2OUTEN
t
1OUTEN
t
RISE
t
FALL
ICS‐41350
DocumentNumber:DS‐000047
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ABSOLUTEMAXIMUMRATINGS
StressabovethoselistedasAbsoluteMaximumRatingsmaycausepermanentdamagetothedevice.Thesearestressratingsonly
andfunctionaloperationofthedeviceattheseconditionsisnotimplied.Exposuretotheabsolutemaximumratingsconditionsfor
extendedperiodsmayaffectdevicereliability.
TABLE7.ABSOLUTEMAXIMUMRATINGS
PARAMETER RATING
SupplyVoltage(V
DD
)−0.3Vto+3.63V
DigitalPinInputVoltage−0.3VtoV
DD
+0.3Vor3.63V,whicheverisless
SoundPressureLevel160dB
MechanicalShock10,000g
VibrationPerMIL‐STD‐883Method2007,TestConditionB
TemperatureRange
Biased−40°Cto+85°C
Storage−55°Cto+150°C
ESDCAUTION


ESD(electrostaticdischarge)sensitivedevice.
Chargeddevicesandcircuitboardscan
dischargewithoutdetection.Althoughthis
productfeaturespatentedorproprietary
protectioncircuitry,damagemayoccuron
devicessubjectedtohighenergyESD.
ThereforeproperESDprecautionsshouldbe
takentoavoidperformancedegradationor
lossoffunctionality.
ICS‐41350
DocumentNumber:DS‐000047
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Revision:1.1
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SOLDERINGPROFILE
Figure2.RecommendedSolderingProfileLimits
TABLE8.RECOMMENDEDSOLDERINGPROFILE*
PROFILEFEATURESn63/Pb37
Pb‐Free
AverageRampRate(T
L
toT
P
)1.25°C/secmax1.25°C/secmax
Preheat
MinimumTemperature
(T
SMIN
)100°C100°C
Maximum
Temperature(T
SMAX
)150°C200°C
Time(T
SMIN
toT
SMAX
),t
S
60secto75sec60secto75sec
Ramp‐UpRate(T
SMAX
toT
L
)1.25°C/sec1.25°C/sec
TimeMaintainedAboveLiquidous(t
L
)45secto75sec~50sec
LiquidousTemperature(T
L
)183°C217°C
PeakTemperature(T
P
)215°C+3°C/−3°C260°C+0°C/−5°C
TimeWithin+5°CofActualPeak
Temperature(t
P
)20secto30sec20secto30sec
Ramp‐DownRate3°C/secmax3°C/secmax
Time+25°C(t
25°C
)toPeakTemperature5minmax5minmax
*ThereflowprofileinTable8isrecommendedforboardmanufacturingwithInvenSenseMEMSmicrophones.Allmicrophonesare
alsocompatiblewiththeJ‐STD‐020profile
t
P
t
L
t
25°C
TO PEAK T EM P ERAT URE
t
S
PREHEAT
CRITIC
A
L ZO NE
T
L
TO T
P
TEMPE
R
A
TURE
TIME
RAMP-DOWN
RAMP-UP
T
SMIN
T
SMAX
T
P
T
L
ICS‐41350
DocumentNumber:DS‐000047
Page10of22
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Revision:1.1
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PINCONFIGURATIONSANDFUNCTIONDESCRIPTIONS
Figure3.PinConfiguration(TopView,TerminalSideDown)
TABLE9.PINFUNCTIONDESCRIPTIONS
PINNAMEFUNCTION
1DATADigitalOutputSignal(DATA1orDATA2)
2SELECT
LeftChannelorRightChannelSelect:
DATA1(right):SELECTtiedtoGND
DATA2(left):SELECTtiedtoVDD.Inthissetting,SELECTshouldbetiedtothesamevoltage
sourceastheVDD
p
in.
3GNDGround
4CLKClockInputtoMicrophone
5VDD
PowerSupply.Forbestperformanceandtoavoidpotentialparasiticartifacts,placea0.1µF
(100nF)ceramictypeX7RcapacitorbetweenPin5(VDD)andground.Placethecapacitoras
closetoPin5aspossible.
DATA
VDD
GND
1
2
3
5
4
SELECT
CLK
ICS‐41350
DocumentNumber:DS‐000047
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TYPICALPERFORMANCECHARACTERISTICS
Figure4.TypicalFrequencyResponse
Figure5.THD+Nvs.InputLevel

Figure6.PowerSupplyRejection(PSR)vs.Frequency
Figure7.Linearity



‐20
‐10
0
10
20
30
10 100 1000 10000
NORMALIZEDAMPLITUDE(dB)
FREQUENCY(Hz)
0.1
1
10
90 100 110 120 130
THD+N(%)
INPUTAMPLITUDE(dBSPL)
LowPowerMode
HighPerformanceMode
StandardMode
‐120
‐100
‐80
‐60
‐40
‐20
0
100 1000 10000
PSR(dBFS)
FREQUENCY(Hz)
‐40
‐30
‐20
‐10
0
90 100 110 120 130
OUTPUTAMPLITUDE(dBFS)
INPUTAMPLITUDE(dBSPL)
Standard&Low
PowerModes
HighPerformance
Mode
ICS‐41350
DocumentNumber:DS‐000047
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THEORYOFOPERATION
PDMDATAFORMAT
TheoutputfromtheDATApinoftheICS‐41350isinpulsedensitymodulated(PDM)format.Thisdataisthe1‐bitoutputofafourth‐
orderΣ‐Δmodulator.ThedataisencodedsothattheleftchannelisclockedonthefallingedgeofCLK,andtherightchannelisclocked
ontherisingedgeofCLK.AfterdrivingtheDATAsignalhighorlowintheappropriatehalfframeoftheCLKsignal,theDATAdriverof
themicrophonetristates.Inthisway,twomicrophones,onesettotheleftchannelandtheothertotheright,candriveasingleDATA
line.SeeFigure1foratimingdiagramofthePDMdataformat;theDATA1andDATA2linesshowninthisfigurearetwohalvesofthe
singlephysicalDATAsignal.Figure8showsadiagramofthetwostereochannelssharingacommonDATAline.
Figure8.StereoPDMFormat
IfonlyonemicrophoneisconnectedtotheDATAsignal,theoutputisonlyclockedonasingleedge(Figure9).Forexample,aleft
channelmicrophoneisneverclockedontherisingedgeofCLK.Inasinglemicrophoneapplication,eachbitoftheDATAsignalis
typicallyheldforthefullCLKperioduntilthenexttransitionbecausetheleakageoftheDATAlineisnotenoughtodischargetheline
whilethedriveristristated.
Figure9.MonoPDMFormat
SeeTable10forthechannelassignmentsaccordingtothelogiclevelontheSELECTpin.
TABLE10.ICS‐41350CHANNELSETTING
ForPDMdata,thedensityofthepulsesindicatesthesignalamplitude.Ahighdensityofhighpulsesindicatesasignalnearpositive
fullscale,andahighdensityoflowpulsesindicatesasignalnearnegativefullscale.Aperfectzero(dc)audiosignalshowsan
alternatingpatternofhighandlowpulses.
TheoutputPDMdatasignalhasadcoffsetofabout3%offullscale.Ahigh‐passfilterinthecodecthatisconnectedtothedigital
microphoneanddoesnotaffecttheperformanceofthemicrophonetypicallyremovesthisdcsignal.
PDMMICROPHONESENSITIVITY
ThesensitivityofaPDMoutputmicrophoneisspecifiedwiththeunitdBFS(decibelsrelativetodigitalfullscale).A0dBFSsine
waveisdefinedasasignalwhosepeakjusttouchesthefull‐scalecodeofthedigitalword(seeFigure10).Thismeasurement
conventionalsomeansthatsignalswithadifferentcrestfactormayhaveanRMSlevelhigherthan0dBFS.Forexample,afull‐scale
squarewavehasanRMSlevelof3dBFS.
Thisdefinitionofa0dBFSsignalmustbeunderstoodwhenmeasuringthesensitivityoftheICS‐41350.A1kHzsinewaveata
94dBSPLacousticinputtotheICS‐41350resultsinanoutputsignalwitha−26dBFSlevelinStandardModeand−32dBFSinHigh
DATA2 ( L ) DATA2 (L )DATA1 (R) DATA1 (R)
CLK
DATA
DATA1 (R) DATA1 (R) DATA1 (R)
CLK
DATA
SELECTPinSettingChannel
Low(tietoGND)Right(DATA1)
High(tietoVDD)Left(DATA2)
ICS‐41350
DocumentNumber:DS‐000047
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Revision:1.1
RevDate:06/23/2016
PerformanceMode.IntheStandardModeexample,theoutputdigitalwordpeaksat−26dBbelowthedigitalfull‐scalelevel.A
commonmisunderstandingisthattheoutputhasanRMSlevelof−29dBFS;however,thisisnottruebecauseofthedefinitionofthe
0dBFSsinewave.
Figure10.1kHz,0dBFSSineWave
Thereisnotacommonlyacceptedunitofmeasurementtoexpresstheinstantaneouslevel,asopposedtotheRMSlevelofthe
signal,ofadigitalsignaloutputfromthemicrophone.Somemeasurementsystemsexpresstheinstantaneouslevelofanindividual
sampleinunitsofD,where1.0Disdigitalfullscale.Inthiscase,a−26dBFSsinewavehaspeaksat0.05D.
1.0
–1.0
–0.8
–0.6
–0.4
–0.2
0
0.2
0.4
0.6
0.8
00.91.00.80.70.60.50.40.30.20.1
DIG IT AL AMP L I T UDE ( D)
TIME (ms)
ICS‐41350
DocumentNumber:DS‐000047
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APPLICATIONSINFORMATION
LOWPOWERMODE
LowPowerMode(LPM)enablestheICS‐41350tobeusedinanAlwaysOnlisteningmodeforkeywordspottingandambientsound
analysis.TheICS‐41350willenterLPMwhenthefrequencyofSCKisbetween400and800kHz.Inthismode,themicrophone
consumesonly185µAwhileretaininghighelectro‐acousticperformance.
WhenonemicrophoneisinLPMforAlwaysOnlistening,asecondmicrophonesharingthesamedatalinemaybepowereddown.In
thiscase,whereonemicrophoneispoweredupandanotherispowereddownbydisablingtheVDDsupplyorinsleepmodeby
reducingthefrequencyofaseparateclocksource,thedisabledmicrophonedoesnotpresentaloadtothesignalontheLPM
microphone’sDATApin.
DYNAMICRANGECONSIDERATIONS
Thefull‐scaledigitaloutput(0dBFS)oftheICS‐41350ismappedtoanacousticinputof126dBSPLinhigh‐performancemode.The
microphoneclips(THD=10%)at126dBSPL(seeFigure5);however,itcontinuestooutputanincreasinglydistortedsignalabove
thatpoint.Thepeakoutputlevel,whichiscontrolledbythemodulator,limitsat0dBFS(seeFigure7).
Tofullyusethe96dBdynamicrangeoftheoutputdataoftheICS‐41350inadesign,thedigitalsignalprocessor(DSP),analog‐to‐digital
converter(ADC),orcodeccircuitfollowingitmustbechosencarefully.ThedecimationfilterthatinputsthePDMsignalfromtheICS‐
41350musthaveadynamicrangesufficientlybetterthanthedynamicrangeofthemicrophonesothattheoverallnoise
performanceofthesystemisnotdegraded.Ifthedecimationfilterhasadynamicrangeof10dBbetterthanthemicrophone,the
overallsystemnoiseonlydegradesby0.4dB.This106dBfilterdynamicrangerequiresthefiltertohaveatleast18bitresolution.
CONNECTINGPDMMICROPHONES
APDMoutputmicrophoneistypicallyconnectedtoacodecwithadedicatedPDMinput.Thiscodecseparatelydecodestheleftandright
channelsandfiltersthehighsampleratemodulateddatabacktotheaudiofrequencyband.Thiscodecalsogeneratestheclockforthe
PDMmicrophonesorissynchronouswiththesourcethatisgeneratingtheclock.Figure11andFigure12showmonoandstereo
connectionsoftheICS‐41350toacodec.ThemonoconnectionshowsanICS‐41350settooutputdataontherightchannel.Tooutput
ontheleftchannel,tietheSELECTpintoVDDinsteadoftyingittoGND.
Figure11.MonoPDMMicrophone(RightChannel)ConnectiontoCodec
CLOCKOUTPUT
CODEC
0.1µF
1
.
8
VTO3
.
3V
GND
SELECT DATA
ICS‐41350 CLK
VDD
DATAINPUT
ICS‐41350
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Figure12.StereoPDMMicrophoneConnectiontoCodec
DecoupletheVDDpinoftheICS‐41350toGNDwitha0.1µFcapacitor.PlacethiscapacitorasclosetoVDDastheprintedcircuitboard
(PCB)layoutallows.
Donotuseapull‐uporpull‐downresistoronthePDMdatasignallinebecauseitcanpullthesignaltoanincorrectstateduringtheperiod
thatthesignallineistristated.
TheDATAsignaldoesnotneedtobebufferedinnormalusewhentheICS‐41350microphone(s)isplacedclosetothecodeconthePCB.If
theDATAsignalmustbedrivenoveralongcable(>15cm)orotherlargecapacitiveload,adigitalbuffermayberequired.Onlyuseasignal
bufferontheDATAlinewhenonemicrophoneisinuseorafterthepointwheretwomicrophonesareconnected(seeFigure13).The
DATAoutputofeachmicrophoneinastereoconfigurationcannotbeindividuallybufferedbecausethetwobufferoutputscannot
driveasinglesignalline.Ifabufferisused,takecaretoselectonewithlowpropagationdelaysothatthetimingofthedata
connectedtothecodecisnotcorrupted.

Figure13.BufferedConnectionsBetweenStereoICS‐41350sandaCodec
CLOCKOUTPUT
CODEC
0.1µF
1
.
8
VTO3
.
3V
GND
SELECT DATA
ICS‐41350 CLK
VDD
DATAINPUT
0.1µF
1.8V TO 3.3V
GND
SELECT DATA
ICS‐41350 CLK
VDD
CLOCKOUTPUT
CODEC
DATA
ICS‐41350
ICS‐41350
CLK
DATA
CLK
DATAINPUT
ICS‐41350
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WhenlongwiresareusedtoconnectthecodectotheICS‐41350,asourceterminationresistorcanbeusedontheclockoutputofthe
codecinsteadofabuffertominimizesignalovershootorringing.Matchthevalueofthisresistortothecharacteristicimpedanceof
theCLKtraceonthePCB.Dependingonthedrivecapabilityofthecodecclockoutput,abuffermaystillbeneeded,asshowninFigure
13.
ULTRASOUNDAPPLICATIONS
InitsHighPerformanceMode,theICS‐41350functionsasanultrasonicsensor,aswellasanaudiobandsensor.Thismicrophone’s
ultrasonicperformancewilldependontheclockfrequency,thelowpassdecimationfilter,thestrengthoftheultrasonicsignalbeing
sensed,andthedesignoftheacousticportthatiscoupledtothemicrophone.Theacousticportdesignisespeciallyimportantat
higherfrequencies,becausethesizeoftheportitselfisontheorderof¼thewavelengthofsoundandtheacousticmassloadingwill
besignificant.Thesewillbothcontributetotheporthavingaconsiderableeffectontheacousticsystem’sresponse.
SLEEPMODE
Themicrophoneenterssleepmodewhentheclockfrequencyfallsbelow200kHz.Inthismode,themicrophonedataoutputisinahigh
impedancestate.Thecurrentconsumptioninsleepmodeislessthan20µA.

TheICS‐41350enterssleepmodewithin1msoftheclockfrequencyfallingbelow200kHz.Themicrophonewakesupfromsleep
modeandbeginstooutputdatawithin20msofwhentheclockbecomesactive.
START‐UPTIME
Thestart‐uptimeoftheICS‐41350islessthan20ms.ThePDMdatafromthemicrophoneisvalidtobeusedassoonasthedatais
beingoutput.
ICS‐41350
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SUPPORTINGDOCUMENTS
Foradditionalinformation,seethefollowingdocuments.
APPLICATIONNOTES
AN‐000048,PDMDigitalOutputMEMSMicrophoneFlexEvaluationBoardUserGuide
AN‐100,MEMSMicrophoneHandlingandAssemblyGuide
AN‐1003,RecommendationsforMountingandConnectingtheInvensense,Bottom‐PortedMEMSMicrophones
AN‐1112,MicrophoneSpecificationsExplained
AN‐1124,RecommendationsforSealingInvenSenseBottom‐PortMEMSMicrophonesfromDustandLiquidIngress
AN‐1140,MicrophoneArrayBeamforming
ICS‐41350
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PCBDESIGNANDLANDPATTERNLAYOUT
TherecommendedPCBlandpatternfortheICS‐41350isa1:1ratioofthesolderpadsonthemicrophonepackage,asshowninFigure
14.AvoidapplyingsolderpastetothesoundholeinthePCB.AsuggestedsolderpastestencilpatternlayoutisshowninFigure15.
TheresponseoftheICS‐41350isnotaffectedbythePCBholesizeaslongastheholeisnotsmallerthanthesoundportofthe
microphone(0.375mmindiameter).A0.5mmto1mmdiameterfortheholeisrecommended.Takecaretoaligntheholeinthe
microphonepackagewiththeholeinthePCB.Theexactdegreeofthealignmentdoesnotaffectthemicrophoneperformanceaslong
astheholesarenotpartiallyorcompletelyblocked.
Figure14.RecommendedPCBLandPatternLayout
Figure15.SuggestedSolderPasteStencilPatternLayout
PCBMATERIALANDTHICKNESS
TheperformanceoftheICS‐41350isnotaffectedbyPCBthickness.TheICS‐41350canbemountedoneitherarigidorflexiblePCB.
AflexiblePCBwiththemicrophonecanbeattacheddirectlytothedevicehousingwithanadhesivelayer.Thismountingmethod
offersareliablesealaroundthesoundportwhileprovidingtheshortestacousticpathforgoodsoundquality.
Ø1.025
Ø1.625
0.522x0.725(4X)
1.252
0.822
1.675
0.838
1.2520.822
1.675
0.1(4x)
Ø1.125
Ø1.625
0.422x0.625(4X)
ICS‐41350
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HANDLINGINSTRUCTIONS
PICKANDPLACEEQUIPMENT
TheMEMSmicrophonecanbehandledusingstandardpick‐and‐placeandchipshootingequipment.Takecaretoavoiddamagetothe
MEMSmicrophonestructureasfollows:
Useastandardpickuptooltohandlethemicrophone.Becausethemicrophoneholeisonthebottomofthepackage,the
pickuptoolcanmakecontactwithanypartofthelidsurface.
Donotpickupthemicrophonewithavacuumtoolthatmakescontactwiththebottomsideofthemicrophone.
Donotpullairoutoforblowairintothemicrophoneport.
DonotuseexcessiveforcetoplacethemicrophoneonthePCB.
REFLOWSOLDER
Forbestresults,thesolderingprofilemustbeinaccordancewiththerecommendationsofthemanufacturerofthesolderpasteusedto
attachtheMEMSmicrophonetothePCB.Itisrecommendedthatthesolderreflowprofilenotexceedthelimitconditionsspecified
inFigure2andTable8.
BOARDWASH
WhenwashingthePCB,ensurethatwaterdoesnotmakecontactwiththemicrophoneport.Donotuseblow‐offproceduresor
ultrasoniccleaning.
ICS‐41350
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OUTLINEDIMENSIONS
Figure16.5‐TerminalChipArraySmallOutlineNoLeadCavity[LGA_CAV]
3.5mm×2.65mm×0.98mmBody
Dimensionsshowninmillimeters
Dimensiontoleranceis±0.15mmunlessotherwisespecified
Figure17.PackageMarkingSpecification(TopView)
ORDERINGGUIDE
PARTTEMPRANGEPACKAGEQUANTITYPACKAGING
ICS‐41350−40°Cto+85°C5‐TerminalLGA_CAV10,000 13”TapeandReel
EV_ICS‐41350‐FX—EvaluationBoard—

BOTTOMVIEW
SIDEVIEW
TOPVIEW
B
d0.10
A
(4X)
f0.10C
C
(2.45)
(3.30)
3.50
2.65
j0.10mCAB
0.522X0.725(4x)
PIN1
CORNER
(0.254)
0.98
1.040
1.33
Ø0.375
Ø1.025
Ø1.625
0.300
1.513
3.500
0.125
0.950
1.675
0.125
2.650
0.82
1
5
2
4
3
PIN1
CORNER
YYXXX
350
LOTTRACEABILITY CODE
PIN1INDIC
TION
P
R
TNUMBE
R
D
AT E CO D E
ICS‐41350
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REVISIONHISTORY
REVISIONDATEREVISIONDESCRIPTION
2/4/20161.0Initialversion
6/23/20161.1UpdatedOrderingGuidequantity
ICS‐41350
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COMPLIANCEDECLARATIONDISCLAIMER
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guaranteeaccuracyorcompleteness.Conformitydocumentssubstantiatingthespecificationsandcomponentcharacteristicsareon
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shouldnotbeusedorsoldinthedevelopment,storage,productionorutilizationofanyconventionalormass‐destructiveweapons
orforanyotherweaponsorlifethreateningapplications,aswellasinanyotherlifecriticalapplicationssuchasmedicalequipment,
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preventionequipment.
©2016InvenSense,Inc.Allrightsreserved.InvenSense,MotionTracking,MotionProcessing,MotionProcessor,MotionFusion,
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