SNOSBW2F –NOVEMBER 1999–REVISED NOVEMBER 2015 …

1 ProductFolderSample &BuyTechnicalDocumentsTools &SoftwareSupport &CommunityLM13700 SNOSBW2F NOVEMBER1999 REVISEDNOVEMBER2015LM13700 Dual OperationalTransconductanceAmplifiersWit h LinearizingDiodesand Buffers1 Features3 DescriptionTheLM13700seriesconsistsof twocurrent-1 gmAdjustableOver6 Decadescontrolledtransconductanceamplifi ers,eachwith ExcellentgmLinearitydifferentialinputsan da ExcellentMatchingBetweenAmplifiersamplif ierssharecommonsuppliesbut LinearizingDiodesfor reducedoutputdistortionprovidedat the inputsto reducedistortionand allow resultis a 10-dBsignal-to- HighOutputSignal-to-NoiseRationoiseimpro vementreferencedto Applicationsespeciallydesignedto complementthe dynamicrangeof the the Current-ControlledAmplifiersLM13700diffe rfromthoseof the LM13600in that StereoAudioAmplifierstheirinputbiascurre nts(andthustheiroutputDC Current-ControlledImpedanceslevels)are independentof IABC.

2 Thismayresultinperformancesuperiorto that of the LM13600in audio Current-ControlledFiltersapplications. Current-ControlledOscillators MultiplexersDeviceInformation(1) TimersPARTNUMBERPACKAGEBODYSIZE(NOM)SOIC (16) Sample-and-HoldCircuitsLM13700 PDIP(16) (1) For all availablepackages,see the orderableaddendumatthe end of the IMPORTANTNOTICEat the end of this datasheetaddressesavailability,warranty, changes,use in safety-criticalapplications,intellectual propertymattersand NOVEMBER1999 Applicationand Pin Configurationand Deviceand Mechanical,Packaging,and RevisionHistoryNOTE:Pagenumbersfor previousrevisionsmay differfrompagenumbersin the (March2013)to RevisionFPage AddedESDR atingstable,FeatureDescriptionsection,De viceFunctionalModes,Applicationand Implementationsection,PowerSupplyRecomme ndationssection,Layoutsection,Deviceand DocumentationSupportsection,andMechanica l,Packaging,and (March2013)

3 To RevisionEPage Changedlayoutof NationalDataSheetto TI 1999 2015, NOVEMBER1999 REVISEDNOVEMBER20155 Pin Configurationand FunctionsD or NFGP ackage16-PinSOICor PDIPTop ViewPin input1, 16 ACurrentbias inputBufferinput7, 10 ABufferamplifierinputBufferoutput8, 9 ABufferamplifieroutputDiodebias2, 15 ALinearizingdiodebias inputInput+3, 14 APositiveinputInput 4, 13 ANegativeinputOutput5, 12 AUnbufferedoutputV+11 PPositivepowersupplyV 6 PNegativepowersupplyCopyright 1999 2015,TexasInstrumentsIncorporatedSubmitD ocumentationFeedback3 ProductFolderLinks:LM13700LM13700 SNOSBW2F NOVEMBER1999 (unlessotherwisenoted)(1)MINMAXUNITS upplyvoltage36 VDCor 18 VDC inputvoltage+VS VSVD ifferentialinputvoltage 5 VDiodebias current(ID)2mAAmplifierbias current(IABC)2mABufferoutputcurrent(2)20 mAPowerdissipation(3)TA= 25 C LM13700N570mWOutputshortcircuitdurationC ontinuousStoragetemperature,Tstg 65150 C(1)StressesbeyondthoselistedunderAbsolu teMaximumRatingsmay causepermanentdamageto the stressratingsonly,whichdo not implyfunctionaloperationof the deviceat theseor any otherconditionsbeyondthoseindicatedunder RecommendedOperatingConditions.

4 Exposureto absolute-maximum-ratedconditionsfor extendedperiodsmay affectdevicereliability.(2)Bufferoutputc urrentshouldbe limitedso as to not exceedpackagedissipation.(3)For operationat ambienttemperaturesabove25 C, the devicemustbe deratedbasedon a 150 C maximumjunctiontemperatureand athermalresistance,junctionto ambient,as follows:LM13700N,90 C/W;LM13700M,110 (unlessotherwisenoted)MINMAXUNITV+ (single-supplyconfiguration) + (dual-supplyconfiguration) (dual-supplyconfiguration) 16 ,TALM13700N070 (1)D (SOIC)NFG(PDIP)UNIT16 PINS16 PINSR C/WR JC(top)Junction-to-case(top) C/WR C/W C/W C/W(1)For moreinformationabouttraditionaland new thermalmetrics,see theSemiconductorand IC PackageThermalMetricsapplicationreport, 1999 2015, NOVEMBER1999 VS= 15 V, TA= 25 C, amplifierbias current(IABC) = 500 A, pins 2 and 15 inputsto the buffersare groundedand outputsare (VOS)mVIABC= 5 current(ID) = 500 A IABC 500 current AOverspecifiedtemperaturerange1867009600 13000 Forwardtransconductance(gm) 0, IABC= 5 A5 PeakoutputcurrentRL= 0, IABC= 500 A350500650 ARL= 0, OverSpecifiedTempRange300 SupplycurrentIABC= 500 A, 12 input(1)

5 Crosstalk100dB20 Hz < f < 20 kHzDifferentialinputcurrentIABC= 0, input= 4 0 (referto test circuit) Open-loopbandwidth2 MHzSlewrateUnitygain compensated50V/ sBufferinputcurrentSee(1) APeakbufferoutputvoltageSee(1)10 VPEAKOUTPUTVOLTAGEP ositiveRL= , 5 A IABC 500 , 5 A IABC 500 A 12 VOS/ V+20150 V/VNegative VOS/ V 20150 V/V(1)Thesespecificationsapplyfor VS= 15 V, IABC= 500 A, ROUT= 5-k connectedfromthe bufferoutputto VSand the inputof thebufferis connectedto the 1999 2015,TexasInstrumentsIncorporatedSubmitD ocumentationFeedback5 ProductFolderLinks:LM13700LM13700 SNOSBW2F NOVEMBER1999 InputOffsetCurrentFigure1. InputOffsetVoltageFigure3. InputBiasCurrentFigure4. PeakOutputCurrentFigure6. LeakageCurrentFigure5. PeakOutputVoltageand CommonModeRange6 SubmitDocumentationFeedbackCopyright 1999 2015, NOVEMBER1999 REVISEDNOVEMBER2015 TypicalCharacteristics(continued)Figure7 .

6 InputLeakageFigure8. TransconductanceFigure9. InputResistanceFigure10. AmplifierBiasVoltagevs. AmplifierBiasCurrentFigure11. Inputand OutputCapacitanceFigure12. OutputResistanceCopyright 1999 2015,TexasInstrumentsIncorporatedSubmitD ocumentationFeedback7 ProductFolderLinks:LM13700LM13700 SNOSBW2F NOVEMBER1999 (continued)Figure13. Distortionvs. DifferentialInputVoltageFigure14. Voltagevs. AmplifierBiasCurrentFigure15. OutputNoisevs Frequency8 SubmitDocumentationFeedbackCopyright 1999 2015, NOVEMBER1999 REVISEDNOVEMBER20157 LM13700is a two inputsincludelinearizingdiodesto reducedistortion,and the outputcurrentis controlledby adedicatedpin. The outputscan sustaina continuousshortto differentialtransistorpair Q4and Q5forma transconductancestagein that the ratioof theircollectorcurrentsis definedby the differentialinputvoltageaccordingto the transferfunction:(1)whereVINis the differentialinputvoltage,kT/qis approximately26 mV at 25 C and I5and I4are the collectorcurrentsof transistorsQ5and exceptionof Q12and Q13, all transistorsand diodesareidenticalin Q2with DiodeD1forma currentmirrorwhichforcesthe sumof currentsI4and I5to equalIABC:I4+ I5= IABC(2)whereIABCis the amplifierbias currentappliedto the gain smalldifferentialinputvoltagesthe ratioof I4and I5approachesunityand the Taylorseriesof the In functionis approximatedas:(3)(4)Copyright 1999 2015,TexasInstrumentsIncorporatedSubmitD ocumentationFeedback9 ProductFolderLinks.

7 LM13700LM13700 SNOSBW2F NOVEMBER1999 (continued)CollectorcurrentsI4and I5are not very usefulby themselvesand it is necessaryto subtractone remainingtransistorsand diodesformthreecurrentmirrorsthat producean outputcurrentequalto I5minusI4thus:(5)The termin bracketsis thenthe transconductanceof the amplifierand is proportionalto differentialvoltagesgreaterthana few millivolts,Equation3 becomesless validand the demonstrateshowthe internaldiodescan linearizethe transferfunctionof the convenienceassumethe diodesare biasedwithcurrentsourcesand the inputsignalis in the formof currentIS. Sincethe sum of I4and I5is IABCand the differenceis IOUT, currentsI4and I5iswrittenas follows:(6)Sincethe diodesand the inputtransistorshaveidenticalgeometriesa nd are subjectto similarvoltagesandtemperatures,the followingis true:(7)Noticethat in derivingEquation7 no approximationshavebeenmadeand thereare no limitationsare that the signalcurrentnot exceedID/ 2 and that the diodesbe biasedwith ,replacingthe currentsourceswith resistorswill singleendedor outputscan supporta sustainedshortto use of the LM13700in 5 V supplysystemsrequireswill reducesignaldynamicrange.

8 This is due to the PNPtransistorshavinga higherVBEthanthe separateoutputbufferwhichconsistsof a Darlingtonpair transistorthat can driveup 1999 2015, NOVEMBER1999 REVISEDNOVEMBER20158 Applicationand ImplementationNOTEI nformationin the followingapplicationssectionsis not partof the TI componentspecification,and TI doesnot warrantits accuracyor s customersareresponsiblefor determiningsuitabilityof componentsfor test theirdesignimplementationto OTAis a versatilebuildingblockanalogcomponenttha t can be consideredan LM13700can be usedin a widevarietyof applications,fromvoltage-controlledampli fiersand filtersto 2 well-matched,independentchannelsmakethe LDC13700well suitedfor this exampleapplication,the systemrequirementsprovidea volumecontrolfor a 1 VPinputsignalwith aTHD< 15 V volumecontrolvariesbetween-13 V and 15 V and needsto provideanadjustablegain rangeof > linearizingdiodesis recommendedfor mostapplications,as they greatlyreducethe requiredthat the diodebias current,IDbe greaterthantwicethe inputcurrent,IS.

9 As the inputvoltagehas aDC levelof 0 V, the DiodeBiasinputpins are 1 diodedropabove0 V, whichis + Tyingthe bias to thecleanV+ supply,resultsin a voltagedropof acrossRD. Usingthe recommended1mAfor IDis appropriatehere,and with VS=+15V, the voltagedropis , and so usingthe standardvalueof 13-k is acceptableandwill providethe desiredgain obtainthe < ,the differentialinputvoltagemustbe <60mVppwhenthe linearizingdiodesare inputdivideron the inputwill reducethe 1 VPinputto 33mVPP, whichis withinthe ,set IBIAS. The BiasInputpins (pins1 or 16), are 2 diodedropsabovethe negativesupply,and thereforeVBIAS= 2(VBE) + V- , whichfor this applicationis To set IBIASto 1mawhenVC= 15 V requiresa ;30-k is a standardvalueand is usedfor this gain will be linearwith the 1999 2015,TexasInstrumentsIncorporatedSubmitD ocumentationFeedback11 ProductFolderLinks:LM13700 Control Voltage (V)Signal Amplitude (dB)-15-10-5051015-35-30-25-20-15-10-50D 001LM13700 SNOSBW2F NOVEMBER1999 (continued) SignalAmplitudevs showshowthe linearizingdiodesis usedin a understandthe inputbiasing,it is bestto considerthe 13-k resistoras a currentsourceand use a Theveninequivalentcircuitasshownin Figure21.

10 This circuitis similarto Figure19 and operatesthe potentiometerin Figure20 isadjustedto minimizethe effectsof the controlsignalat the LinearizingDiodesFor optimumsignal-to-noiseperformance,IABC shouldbe as largeas possibleas shownby the inputsignalalso improvethe S/N linearizingdiodeshelp hereby allowinglargerinputsignalsfor the sameoutputdistortionas shownby the Distortionvs. may be optimizedby adjustingthe magnitudeof the inputsignalvia RIN(Figure20) untilthe outputdistortionis belowthe outputvoltageswingcan thenbe set at any levelby noisecontributionof the linearizingdiodesis negligiblerelativeto the contributionof the amplifier'sinternaltransistors,IDshouldb e as largeas dynamicjunctionresistanceof thediodes(re) and maximizestheirlinearizingactionwhenbalan cedagainstRIN. A valueof 1 mA is recommendedfor IDunlessthe 1999 2015, NOVEMBER1999 REVISEDNOVEMBER2015 SystemExamples(continued)Figure20.