LTC3210-2/LTC3210-3
MAIN/CAM LED Controllers
with 32-Step Brightness Control
in 3mm × 3mm QFN
FeaTures
DescripTion
TheꢀLTC®3210-2/LTC3210-3ꢀareꢀlowꢀnoiseꢀchargeꢀpumpꢀ
DC/DCꢀconvertersꢀdesignedꢀtoꢀdriveꢀthreeꢀorꢀfourꢀMAINꢀ
LEDsꢀandꢀoneꢀhighꢀcurrentꢀCAMꢀLEDꢀforꢀcameraꢀlighting.ꢀ
TheꢀLTC3210-2/LTC3210-3ꢀrequireꢀonlyꢀfourꢀsmallꢀceramicꢀ
capacitorsꢀandꢀtwoꢀcurrentꢀsetꢀresistorsꢀtoꢀformꢀaꢀcompleteꢀ
LEDꢀpowerꢀsupplyꢀandꢀcurrentꢀcontroller.
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ꢀ Low Noise Charge Pump Provides High Efficiency
with Automatic Mode Switching
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ꢀ Multimode Operation: 1x, 1.5x, 2x
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ꢀ Individual Full-Scale Current Set Resistors
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ꢀ Up to 500mA Total Output Current
ꢀ Single Wire EN/Brightness Control for MAIN and
CAM LEDs
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Built-inꢀsoft-startꢀcircuitryꢀpreventsꢀexcessiveꢀinrushꢀcur-
rentꢀduringꢀstart-upꢀandꢀmodeꢀchanges.ꢀHighꢀswitchingꢀ
frequencyꢀenablesꢀtheꢀuseꢀofꢀsmallꢀexternalꢀcapacitors.ꢀ
IndependentꢀMAINꢀandꢀCAMꢀfull-scaleꢀcurrentꢀsettingsꢀ
areꢀprogrammedꢀbyꢀtwoꢀexternalꢀresistors.ꢀ
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ꢀ 32:1 Linear Brightness Control Range for
MAIN Display
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ꢀ ThreeꢀorꢀFourꢀ25mAꢀLowꢀDropoutꢀMAINꢀLEDꢀOutputs
ꢀ Oneꢀ400mAꢀLowꢀDropoutꢀCAMꢀLEDꢀOutput
ꢀ LowꢀNoiseꢀConstantꢀFrequencyꢀOperation*
ꢀ LowꢀShutdownꢀCurrent:ꢀ3µAꢀ
ꢀ InternalꢀSoft-StartꢀLimitsꢀInrushꢀCurrentꢀDuringꢀ
StartupꢀandꢀModeꢀSwitching
Shutdownꢀmodeꢀandꢀcurrentꢀoutputꢀlevelsꢀareꢀselectedꢀ
viaꢀtwoꢀlogicꢀinputs.ꢀENMꢀandꢀENCꢀareꢀtoggledꢀtoꢀadjustꢀ
theꢀLEDꢀcurrentsꢀviaꢀinternalꢀcountersꢀandꢀDACs.ꢀAꢀ5-bitꢀ
linearꢀDACꢀ(32ꢀsteps)ꢀprovidesꢀhighꢀresolutionꢀbrightnessꢀ
controlꢀforꢀtheꢀMAINꢀdisplay.
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ꢀ Open/ShortꢀLEDꢀProtection
ꢀ NoꢀInductors
Theꢀchargeꢀpumpꢀoptimizesꢀefficiencyꢀbasedꢀonꢀtheꢀvolt-
ageꢀacrossꢀtheꢀLEDꢀcurrentꢀsources.ꢀTheꢀpartꢀpowersꢀupꢀ
inꢀ1xꢀmodeꢀandꢀwillꢀautomaticallyꢀswitchꢀtoꢀboostꢀmodeꢀ
wheneverꢀ anyꢀ enabledꢀ LEDꢀ currentꢀ sourceꢀ beginsꢀ toꢀ
enterꢀdropout.ꢀTheꢀLTC3210-2/LTC3210-3ꢀareꢀavailableꢀ
inꢀaꢀ3mmꢀ×ꢀ3mmꢀ16-leadꢀQFNꢀpackage.
ꢀ 3mmꢀ×ꢀ3mmꢀ16-LeadꢀPlasticꢀQFNꢀPackage
applicaTions
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ꢀ Multi-LEDꢀLightꢀSupplyꢀforꢀCellphones/DSCs/PDAs
L,ꢀLT,ꢀLTC,ꢀLTM,ꢀLinearꢀTechnologyꢀandꢀtheꢀLinearꢀlogoꢀareꢀregisteredꢀtrademarksꢀofꢀLinearꢀ
TechnologyꢀCorporation.ꢀAllꢀotherꢀtrademarksꢀareꢀtheꢀpropertyꢀofꢀtheirꢀrespectiveꢀowners.ꢀ
ProtectedꢀbyꢀU.S.ꢀPatentsꢀincludingꢀ6411531.
Typical applicaTion
C2
2.2µF
C3
2.2µF
4-LED MAIN Display
Efficiency vs VBAT Voltage
100
90
C1P C1M
BAT
C2P
C2M
MAIN
CAM
80
70
60
50
40
30
V
BAT
V
CPO
C1
2.2µF
C4
2.2µF
LTC3210-2
MLED1
MLED2
MLED3
MLED4
CLED
ENM
ENC
ENM
ENC
20
4 LEDs AT 9mA/LED
(TYP V AT 9mA = 3V, NICHIA NSCW100)
F
10
321023 TA01
T
= 25°C
A
0
RM
RC
GND
3.0 3.2 3.4 3.6 3.8 4.0 4.2 4.4
30.1k
1%
24.3k
1%
V
(V)
BAT
321023 TA01b
321023fb
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