Datasheet

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9.2RecommendedOscillatorCircuit
Osc
Circuit
XO
XI
C
1
C
2
r
d
AVSS
TAS3108/TAS3108IA
S0114-01
9.3RecommendedPCBDesignforTAS3108IAApplications
TAS3108,TAS3108IA
AUDIODIGITALSIGNALPROCESSORS
SLES152B–OCTOBER2005–REVISEDNOVEMBER2007
•MCLKIandXTLIarelogicallyORedtogether,meaningthatwhentheXTALIpinisused,theMCLKIpin
mustbegrounded.
•Crystaltype=Parallel-mode,fundamental-modecrystal
•r
d
=Drive-levelcontrolresistor–vendorspecified
•C
L
=Crystalloadcapacitance(capacitanceofcircuitrybetweenthetwoterminalsofthecrystal)
•C
L
=(C
1
×C
2
)/C
1
+C
2
)+C
S
(whereC
S
=boardstraycapacitance,~2pF)
AutomotiveapplicationsrequirethattheTAS3108IAoperatesproperlywhileinanambienttemperature
rangeof–40°Cto105°C.Underthehigh-temperatureconditionof105°Cambient,theTAS3108IA
thermalpadmustbesolderedtoacopperareaonthePCBdesignedforthermalrelief.
High-temperatureapplicationsalsorequirethattheapplicationbebuiltonahigh-KdielectricPCB.
High-KdielectricPCBrequirementsforusingTAS3108IAwithsolderedthermalpad:
•0.062inthick
•Minimum3-in×3-inPCB
•2-ozcoppertraceslocatedontopoftheboard(0,071mmthick)
•CopperarealocatedonthetopandbottomofthePCBforsoldering
•Powerandgroundplanes,1-oz.copper(0,036mmthick)
•Thermalvias,0.3-mmdiameter,1.5-mmpitch
•Thermalisolationofpowerplane
Ifthetargetapplicationlimitstheambienttemperatureto0°Cto70°C(standardcommercial
temperaturerange),thethermalpaddoesnotneedtobesolderedtothePCB.
Formoreinformation,seePowerPAD™ThermallyEnhancedPackage(SLMA002 )andPowerPAD
TM
MadeEasy(SLMA004).
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Not Recommended for New Designs