LM4670

Features:

No output filter required for inductive loads
Externally configurable gain
Very fast turn on time: 1.35ms (typ)
Minimum external components
"Click and pop"suppression circuitry
Micro-power shutdown mode
Short circuit protection
Available in space-saving microSMD and LLP packages




Application

Mobile phones
PDAs
Portable electronic devices




Pinout






Specifications

Supply Voltage (Note1) 6.0V
Storage Temperature −65˚Cto+150˚C
Voltage at Any Input Pin V_DD+0.3VVGND-0.3V
Power Dissipation (Note3) InternallyLimited
ESD Susceptibility (Note4) 2.0kV
ESDSusceptibility(Note5) 200V
Junction Temperature(T_JMAX)150˚C
Thermal Resistance
_JA (micro SMD)220˚C/W
_JA(LLP) 64˚C/W
_JC(LLP) TBD˚C/W
Soldering Information
See AN-1112" micro SMD Wafers Level Chip Scale Package."
Operating Ratings (Note1)(Note2)
Temperature Range
T_MINT_AT_MAX−40˚CTA85˚C
Supply Voltage 2.4VV_DD5.5V




Description

The LM4670 is a fully integrated single-supplyhighefficiency switchingaudioamplifier.Itfeaturesaninnovativemodulator thateliminatestheLCoutputfilterusedwithtypicalswitching amplifiers.Eliminatingtheoutputfilterreducesexternalcom- ponentcount,simplifiescircuitdesign,andreducesboard area.TheLM4670processesanaloginputswithadelta-sigmamodulationtechniquethatlowersoutputnoiseand THDwhencomparedtoconventionalpulsewidthmodula-
tors. TheLM4670isdesignedtomeetthedemandsofmobile phonesandotherportablecommunicationdevices.Operat-ingonasingle5Vsupply,itiscapableofdrivinga4
Ω speakerloadatacontinuousaverageoutputof2.3Wwith lessthan1%THD+N.Itsflexiblepowersupplyrequirements allowoperationfrom2.4Vto5.5V.
TheLM4670hashighefficiencywithspeakerloadscom-paredtoatypicalClassABamplifier.Witha3.6Vsupply drivingan8Ω speaker,theIC'sefficiencyfora100mW
powerlevelis77%,reaching88%at600mWoutputpower.
TheLM4670featuresalow-powerconsumptionshutdown
mode.ShutdownmaybeenabledbydrivingtheShutdown
pintoalogiclow(GND).
ThegainoftheLM4670isexternallyconfigurablewhich
allowsindependentgaincontrolfrommultiplesourcesby
summingthesignals.