Product Sample & Technical Tools & Support & Folder Buy Documents Software Community VCA820 SBOS395D–OCTOBER2007–REVISEDSEPTEMBER2015 VCA820 Wideband, > 40-dB Adjust Range, Linear in dB Variable Gain Amplifier 1 Features The VCA820 internal architecture consists of two input buffers and an output current feedback amplifier • 150-MHzSmall-SignalBandwidth 1 stage, integrated with a multiplier core to provide a • 137-MHz,5-VPPBandwidth(G=+10V/V) complete variable gain amplifier (VGA) system that • 0.1-dBGainFlatnessto28MHz does not require external buffering. The maximum gain is set externally with two resistors, providing • 1700-V/μsSlewRate flexibility in designs. The maximum gain is intended • >40-dBGainAdjustRange to be set between +2 V/V and +100 V/V. Operating • HighGainAccuracy:20dB ±0.4dB from ±5-V supplies, the gain control voltage for the VCA820 adjusts the gain linearly in dB as the control • HighOutputCurrent:160mA voltage varies from 0 V to +2 V. For example, set for a maximum gain of +10 V/V, the VCA820 provides 20 2 Applications dB, at +2-V input, to –20 dB at 0-V input of gain • AGCReceiversWithRSSI control range. The VCA820 offers excellent gain • DifferentialLineReceivers linearity. For a 20-dB maximum gain, and a gain- control input voltage varying between 1 V and 2 V, • PulseAmplitudeCompensation the gain does not deviate by more than ±0.4dB • VariableAttenuators (maximumat+25°C). 3 Description DeviceInformation(1) The VCA820 is a dc-coupled, wideband, linear in dB, PARTNUMBER PACKAGE BODYSIZE(NOM) continuously variable, voltage-controlled gain SOIC(14) 8.65mm×3.91mm amplifier. The VCA820 provides a differential input to VCA820 VSSOP(10) 3.00mm×3.00mm single-ended conversion with a high-impedance gain control input, used to vary the gain down 40 dB from (1) For all available packages, see the orderable addendum at the nominal maximum gain set by the gain resistor theendofthedatasheet. (R )andfeedbackresistor(R ). G F space space space WidebandDifferentialtoSingle-EndedAmplifier Common-ModeRejectionRatio 1 kΩ V +V 95 IN+ IN R RG+ FB B) 90 S d 200Ω VCA820 o ( 85 VIN- R R-VGI-N 20Ω ection Rati 787500 S ej R 65 Av = 20 dB e od 60 M n- 55 o m 50 m Co 45 Input-Referred 40 100k 1M 10M 100M Frequency (Hz) 1 An IMPORTANT NOTICE at the end of this data sheet addresses availability, warranty, changes, use in safety-critical applications, intellectualpropertymattersandotherimportantdisclaimers.PRODUCTIONDATA.

VCA820 SBOS395D–OCTOBER2007–REVISEDSEPTEMBER2015 www.ti.com Table of Contents 1 Features.................................................................. 1 8.2 FunctionalBlockDiagram.......................................23 2 Applications........................................................... 1 8.3 FeatureDescription.................................................23 3 Description............................................................. 1 8.4 DeviceFunctionalModes........................................24 4 RevisionHistory..................................................... 2 9 ApplicationandImplementation........................ 27 9.1 ApplicationInformation............................................27 5 DeviceOptions....................................................... 3 9.2 TypicalApplications................................................29 6 PinConfigurationandFunctions......................... 3 9.3 SystemExamples...................................................35 7 Specifications......................................................... 4 10 PowerSupplyRecommendations..................... 37 7.1 AbsoluteMaximumRatings......................................4 11 Layout................................................................... 37 7.2 ESDRatings..............................................................4 11.1 LayoutGuidelines.................................................37 7.3 RecommendedOperatingConditions.......................4 11.2 LayoutExample....................................................38 7.4 ThermalInformation..................................................4 11.3 ThermalConsiderations........................................38 7.5 ElectricalCharacteristics:V =±5V.........................5 S 12 DeviceandDocumentationSupport................. 39 7.6 TypicalCharacteristics:V =±5V,DCParameters.9 S 7.7 TypicalCharacteristics:V =±5V,DCandPower- 12.1 DeviceSupport......................................................39 S SupplyParameters..................................................10 12.2 CommunityResources..........................................39 7.8 TypicalCharacteristics:V =±5V,A =6dB..11 12.3 Trademarks...........................................................39 S VMAX 7.9 TypicalCharacteristics:V =±5V,A =20dB 15 12.4 ElectrostaticDischargeCaution............................39 S VMAX 7.10 TypicalCharacteristics:V =±5V,A =40 12.5 Glossary................................................................39 S VMAX dB.............................................................................19 13 Mechanical,Packaging,andOrderable 8 DetailedDescription............................................ 23 Information........................................................... 39 8.1 Overview.................................................................23 4 Revision History NOTE:Pagenumbersforpreviousrevisionsmaydifferfrompagenumbersinthecurrentversion. ChangesfromRevisionC(October2009)toRevisionD Page • AddedESDRatingstable,FeatureDescriptionsection,DeviceFunctionalModes,ApplicationandImplementation section,PowerSupplyRecommendationssection,Layoutsection,DeviceandDocumentationSupportsection,and Mechanical,Packaging,andOrderableInformationsection.................................................................................................. 1 ChangesfromRevisionB(December2008)toRevisionC Page • DeletedleadtemperaturespecificationfromAbsoluteMaximumRatingstable ................................................................... 4 • ChangedFigure13;correctedy-axisunitsfromV (mV)toV (mV).............................................................................. 11 IN OUT • ChangedFigure14;correctedy-axisunitsfromV (mV)toV (V)................................................................................. 11 IN OUT • ChangedFigure33;correctedy-axisunitsfromV (mV)toV (mV).............................................................................. 15 IN OUT • ChangedFigure34;correctedy-axisunitsfromV (mV)toV (V)................................................................................. 15 IN OUT • ChangedFigure54;correctedy-axisunitsfromV (mV)toV (mV).............................................................................. 19 IN OUT • ChangedFigure55;correctedy-axisunitsfromV (mV)toV (V),correctedV valueingraph.................................. 19 IN OUT IN ChangesfromRevisionA(August2008)toRevisionB Page • RevisedsecondparagraphoftheWidebandVariableGainAmplifierOperationsectiondescribingpin9......................... 29 2 SubmitDocumentationFeedback Copyright©2007–2015,TexasInstrumentsIncorporated ProductFolderLinks:VCA820

VCA820 www.ti.com SBOS395D–OCTOBER2007–REVISEDSEPTEMBER2015 5 Device Options Table1.WidebandVariableGainAmplifiers-VGAs GAINADJUSTRANGE INPUTNOISE SINGLES DUALS (dB) (nV/√Hz) SIGNALBANDWIDTH(MHz) VCA810 — 80 2.4 35 — VCA2612 45 1.25 80 — VCA2613 45 1 80 — VCA2615 52 0.8 50 — VCA2617 48 4.1 50 VCA820 — 40 8.2 150 VCA821 — 40 7.0 420 VCA822 — 40 8.2 150 VCA824 — 40 7.0 420 6 Pin Configuration and Functions DPackage 14-PinSOIC DGSPackage TopView 10-PinVSSOP TopView V+ 1 14 V+ I- 1 10 GND V 2 13 NC G +V 2 9 V OUT +V 3 12 I- IN V 3 8 -V G +R 4 11 GND G +V 4 7 -V IN IN -R 5 10 V G OUT +R 5 6 -R G G -V 6 9 V IN REF V- 7 8 V- PinFunctions PIN I/O DESCRIPTION NAME SOIC VSSOP GND 11 10 — Ground I– 12 1 I FeedbackResistorInput –R 5 6 I GainSetResistor G +R 4 5 I GainSetResistor G V– 7,8 — P NegativeSupply V+ 1,14 — P PositiveSupply –V — 8 P NegativeSupply +V — 2 P PositiveSupply V 2 3 I GainControl G –V 6 7 I InvertingInput IN +V 3 4 I NoninvertingInput IN V 10 9 O Output OUT V 9 — I OutputVoltageReference REF Copyright©2007–2015,TexasInstrumentsIncorporated SubmitDocumentationFeedback 3 ProductFolderLinks:VCA820

VCA820 SBOS395D–OCTOBER2007–REVISEDSEPTEMBER2015 www.ti.com 7 Specifications 7.1 Absolute Maximum Ratings overoperatingfree-airtemperaturerange(unlessotherwisenoted)(1) MIN MAX UNIT Powersupply ±6.3 V Internalpowerdissipation SeeThermalInformation Inputvoltage ±V V S Junctiontemperature(T) 150 °C J Junctiontemperature(T),maximumcontinuousoperation 140 °C J Storagetemperature –65 125 °C (1) StressesbeyondthoselistedunderAbsoluteMaximumRatingsmaycausepermanentdamagetothedevice.Thesearestressratings only,whichdonotimplyfunctionaloperationofthedeviceattheseoranyotherconditionsbeyondthoseindicatedunderRecommended OperatingConditions.Exposuretoabsolute-maximum-ratedconditionsforextendedperiodsmayaffectdevicereliability. 7.2 ESD Ratings VALUE UNIT Humanbodymodel(HBM),perANSI/ESDA/JEDECJS-001(1) ±2000 Chargeddevicemodel(CDM),perJEDECspecificationJESD22- ±500 V(ESD) Electrostaticdischarge C101(2) V Machinemodel(MM) ±200 (1) JEDECdocumentJEP155statesthat500-VHBMallowssafemanufacturingwithastandardESDcontrolprocess. (2) JEDECdocumentJEP157statesthat250-VCDMallowssafemanufacturingwithastandardESDcontrolprocess. 7.3 Recommended Operating Conditions overoperatingfree-airtemperaturerange(unlessotherwisenoted) MIN NOM MAX UNIT Operatingvoltage 7 10 12 V Operatingtemperature –40 25 85 °C 7.4 Thermal Information VCA820 THERMALMETRIC(1) D[SOIC] DGS[VSSOP] UNIT 14PINS 10PINS R Junction-to-ambientthermalresistance 80 130 °C/W θJA R Junction-to-case(top)thermalresistance 49.8 46.6 °C/W θJC(top) R Junction-to-boardthermalresistance 44.9 94.3 °C/W θJB ψ Junction-to-topcharacterizationparameter 13.8 2.2 °C/W JT ψ Junction-to-boardcharacterizationparameter 44.6 92.7 °C/W JB R Junction-to-case(bottom)thermalresistance n/a n/a °C/W θJC(bot) (1) Formoreinformationabouttraditionalandnewthermalmetrics,seetheSemiconductorandICPackageThermalMetricsapplication report,SPRA953. 4 SubmitDocumentationFeedback Copyright©2007–2015,TexasInstrumentsIncorporated ProductFolderLinks:VCA820

VCA820 www.ti.com SBOS395D–OCTOBER2007–REVISEDSEPTEMBER2015 7.5 Electrical Characteristics: V = ±5 V S AtA =20dB,R =1kΩ,R =200Ω,andR =100Ω,unlessotherwisenoted. VMAX F G L TEST PARAMETER TESTCONDITIONS MIN TYP MAX UNIT LEVEL(1) ACPERFORMANCE A =6dB,V =1 VMAX O T =25°C 168 V ,V =+2V J PP G Small-signalbandwidth(SO-14 A =20dB,V =1 VMAX O T =25°C 150 MHz C package) V ,V =+2V J PP G A =40dB,V =1 VMAX O T =25°C 118 V ,V =+2V J PP G A =20dB,V =5 Large-signalbandwidth VMAX O T =25°C 137 MHz C V ,V =+2V J PP G T =25°C 170 200 J T =0°Cto70°C(2) 170 Gaincontrolbandwidth V =1V +10mV J MHz B G DC PP T =–40°Cto 85J°C(2) 165 A =20dB,V =1 Bandwidthfor0.1dBflatness VMAX O T =25°C 28 MHz C V ,V =+2V J PP G T =25°C 1500 1700 J A =20dB,V =5-V T =0°Cto70°C(2) 1500 Slewrate VMAX O J V/μs B step,V =+2V G T =–40°Cto 85J°C(2) 1450 T =25°C 2.5 3.1 J A =20dB,V =5-V T =0°Cto70°C(2) 3.2 Rise-and-falltime VMAX O J ns B step,V =+2V G T =–40°Cto 85J°C(2) 3.2 A =20dB,V =5-V Settlingtimeto0.01% VMAX O T =25°C 11 ns C step,V =+2V J G Harmonicdistortion T =25°C –60 –62 J T =0°Cto70°C(2) –60 2nd-harmonic V =2V ,f=20MHz J dBc B O PP T =–40°Cto 85J°C(2) –60 T =25°C –66 –68 J T =0°Cto70°C(2) –66 3rd-harmonic V =2V ,f=20MHz J dBc B O PP T =–40°Cto 85J°C(2) –66 Inputvoltagenoise f>100kHz T =25°C 8.2 nV/√Hz C J Inputcurrentnoise f>100kHz T =25°C 2.6 pA/√Hz J GAINCONTROL T =25°C ±0.1 ±0.4 J T =0°Cto70°C(2) ±0.5 Absolutegainerror A =20dB,V =2V J dB A VMAX G T =–40°Cto 85J°C(2) ±0.6 V T =25°C 0.85 V C CTRL0 J V T =25°C 0.09 V C SLOPE J T =25°C ±0.3 ±0.4 J A =20dB,V =1V, T =0°Cto70°C(2) ±0.5 Absolutegainerror VMAX G J dB A (G=18.06dB) T =–40°Cto 85J°C(2) ±0.6 (1) Testlevels:(A)100%testedat+25°C.Overtemperaturelimitssetbycharacterizationandsimulation.(B)Limitssetbycharacterization andsimulation.(C)Typicalvalueonlyforinformation. (2) Junctiontemperature=ambientatlowtemperaturelimit;junctiontemperature=ambient+23°Cathightemperaturelimitforover temperaturespecifications. Copyright©2007–2015,TexasInstrumentsIncorporated SubmitDocumentationFeedback 5 ProductFolderLinks:VCA820

VCA820 SBOS395D–OCTOBER2007–REVISEDSEPTEMBER2015 www.ti.com Electrical Characteristics: V = ±5 V (continued) S AtA =20dB,R =1kΩ,R =200Ω,andR =100Ω,unlessotherwisenoted. VMAX F G L TEST PARAMETER TESTCONDITIONS MIN TYP MAX UNIT LEVEL(1) T =25°C –26 –24 J T =0°Cto70°C(2) –24 GainatV =0.2V Relativetomaximumgain J dB A G T =–40°Cto 85J°C(2) –23 T =25°C –26 –24 J T =0°Cto70°C(2) –24 GainatV =0.2V Relativetomaximumgain J dB A G T =–40°Cto 85J°C(2) –23 T =25°C 10 16 J T =0°Cto70°C(2) 16.6 Gaincontrolbiascurrent J μA A T =–40°Cto 85J°C(2) 16.7 T =0°Cto70°C(2) ±12 J Averagegaincontrol biascurrentdrift T85J°=C–(24)0°Cto ±12 nA/°C B Gaincontrolinputimpedance T =25°C 70||1 kΩ||pF C J DCPERFORMANCE T =25°C ±4 ±17 J A =20dB,V =0 T =0°Cto70°C(2) ±17.8 Inputoffsetvoltage VMAX CM J mV A V,V =1V G T =–40°Cto 85J°C(2) ±19 T =0°Cto70°C(2) 30 J Averageinputoffset A =20dB,V =0 voltagedrift VV,MVAGX=1V CM T85J°=C–(24)0°Cto 30 μV/°C B T =25°C 19 25 J A =20dB,V =0 T =0°Cto70°C(2) 29 Inputbiascurrent VMAX CM J μA A V,V =1V G T =–40°Cto 85J°C(2) 31 T =0°Cto70°C(2) 90 J Averageinputbias A =20dB,V =0 currentdrift VV,MVAGX=1V CM T85J°=C–(24)0°Cto 90 nA/°C B T =25°C ±0.5 ±2.5 J A =20dB,V =0 T =0°Cto70°C(2) ±3.2 Inputoffsetcurrent VMAX CM J μA A V,V =1V G T =–40°Cto 85J°C(2) ±3.5 T =0°Cto70°C(2) ±16 J Averageinputoffset A =20dB,V =0 currentdrift VV,MVAGX=1V CM T85J°=C–(24)0°Cto ±16 nA/°C B T =25°C ±2.6 ±2.55 J Maximumcurrentthroughgain T =0°Cto70°C(2) ±2.55 J mA B resistance T =–40°Cto 85J°C(2) ±2.5 6 SubmitDocumentationFeedback Copyright©2007–2015,TexasInstrumentsIncorporated ProductFolderLinks:VCA820

VCA820 www.ti.com SBOS395D–OCTOBER2007–REVISEDSEPTEMBER2015 Electrical Characteristics: V = ±5 V (continued) S AtA =20dB,R =1kΩ,R =200Ω,andR =100Ω,unlessotherwisenoted. VMAX F G L TEST PARAMETER TESTCONDITIONS MIN TYP MAX UNIT LEVEL(1) INPUT T =25°C +1.6 +1.6 J Mostpositivecommon-mode T =0°Cto70°C(2) +1.6 R =100Ω J V A inputvoltage L T =–40°Cto 85J°C(2) +1.6 T =25°C –2.1 –2.1 J Mostnegativecommon-mode T =0°Cto70°C(2) –2.1 R =100Ω J V A inputvoltage L T =–40°Cto 85J°C(2) –2.1 T =25°C 65 80 J T =0°Cto70°C(2) 60 Common-moderejectionratio V =±0.5V J dB A CM T =–40°Cto 85J°C(2) 60 Inputimpedance Differential T =25°C 0.5||1 MΩ||pF C J Common-mode T =25°C 0.5||2 MΩ||pF C J OUTPUT T =25°C ±3.8 ±4.0 J T =0°Cto70°C(2) ±3.75 R =1kΩ J V A L T =–40°Cto 85J°C(2) ±3.7 Outputvoltageswing T =25°C ±3.7 ±3.9 J T =0°Cto70°C(2) ±3.6 R =100Ω J V A L T =–40°Cto 85J°C(2) ±3.5 T =25°C ±140 ±160 J T =0°Cto70°C(2) ±130 Outputcurrent V =0V,R =5Ω J mA A O L T =–40°Cto 85J°C(2) ±130 A =20dB,f>100 Outputimpedance VMAX T =25°C 0.01 Ω C kHz,V =+2V J G POWERSUPPLY Specifiedoperatingvoltage T =25°C ±5 V C J Minimumoperatingvoltage T =25°C ±3.5 V C J T =25°C ±6 J T =0°Cto70°C(2) ±6 Maximumoperatingvoltage J V A T =–40°Cto 85J°C(2) ±6 T =25°C 34 35 J T =0°Cto70°C(2) 35.5 Maximumquiescentcurrent V =1V J mA A G T =–40°Cto 85J°C(2) 36 T =25°C 34 32.5 J T =0°Cto70°C(2) 32 Minimumquiescentcurrent V =1V J mA A G T =–40°Cto 85J°C(2) 31.5 Copyright©2007–2015,TexasInstrumentsIncorporated SubmitDocumentationFeedback 7 ProductFolderLinks:VCA820

VCA820 SBOS395D–OCTOBER2007–REVISEDSEPTEMBER2015 www.ti.com Electrical Characteristics: V = ±5 V (continued) S AtA =20dB,R =1kΩ,R =200Ω,andR =100Ω,unlessotherwisenoted. VMAX F G L TEST PARAMETER TESTCONDITIONS MIN TYP MAX UNIT LEVEL(1) T =25°C –61 –68 J Power-supplyrejectionratio T =0°Cto70°C(2) –59 J dB A (–PSRR) T =–40°Cto 85J°C(2) –58 8 SubmitDocumentationFeedback Copyright©2007–2015,TexasInstrumentsIncorporated ProductFolderLinks:VCA820

VCA820 www.ti.com SBOS395D–OCTOBER2007–REVISEDSEPTEMBER2015 7.6 Typical Characteristics: V = ±5 V, DC Parameters S AtT =+25°C,R =100Ω,V =+1V,andV =single-endedinputon+V with–V atground,unlessotherwisenoted. A L G IN IN IN 10 40 )P IVRIGN MMAAXX(=V P2P.6) m= A2´RG´IRGMAX(AP) dB) 35 IARVGM=A X2(.V6/mVA) = 2´[RF/VIN(VPP)]´2´IRG(AP) VP e ( e ( ng 30 g a a R erential Input Volt 1 mum Gain Adjust 22115050 VO=V 2OV=P P1VPP VO= 4VPP Diff Maxi 5 VO= 3VPP 0.1 0 10 100 1k 100 1k 10k Gain Resistor (W) Feedback Resistor (W) Figure1.MaximumDifferentialInputVoltagevsGain Figure2.MaximumGainAdjustRangevsFeedback Resistor Resistor 60 12 I = 2.6mA Absolute B) A (V/V) = 2´[R/V (V )]´R2G´I (A ) Error e (d 50 VMAX F IN PP RG P 10 Gain Adjust Rang 4300 RF= 500W RF= 3kWRF= 4kW RF= 5kW Gain (V/V) 86 AbsEolruroter RMealaxtiimveu mEr Groar itno m 20 4 mu RF= 1kW xi 10 2 Ma RF= 1.5kW R = 2kW F 0 0 0.1 1 10 0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0 Output Voltage (VPP) Control Voltage (V) Figure3.MaximumGainAdjustRangevsPeak-to-Peak Figure4.GainErrorBandvsGainControlVoltage OutputVoltage 40 1500 20 1400 W) 1300 Gain (V/V) --24000 Equation A(V/V) = K´RRGF ´ 1 + e(V1VGS0L-O PVEG) back Resistor ( 111210000000 d -60 Fee 900 Data -80 VCTRL0= 0.85V 800 NOTE:-3dB bandwidth will vary with the package. V = 90mV See the Application section for more details. -100 SLOPE 700 0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0 1 10 100 Control Voltage (V) AVMAX(V/V) Figure5.NominalGainvsCalculatedGain Figure6.RecommendedR andR vsA F G VMAX Copyright©2007–2015,TexasInstrumentsIncorporated SubmitDocumentationFeedback 9 ProductFolderLinks:VCA820

VCA820 SBOS395D–OCTOBER2007–REVISEDSEPTEMBER2015 www.ti.com 7.7 Typical Characteristics: V = ±5 V, DC and Power-Supply Parameters S AtT =+25°C,R =100Ω,V =+1V,andV =single-endedinputon+V with–V atground,unlessotherwisenoted. A L G IN IN IN 36 36 35 35 div) -IQ div) -IQ A/ 34 A/ 34 nt (m 33 +IQ nt (m 33 e e urr urr nt C 32 nt C 32 ce ce +IQ s 31 s 31 e e ui ui Q Q 31 31 29 29 0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0 0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0 Gain Control Voltage (V) Gain Control Voltage (V) Figure7.SupplyCurrentvsControlVoltage(A =6dB) Figure8.SupplyCurrentvsControlVoltage(A =20dB) VMAX VMAX 36 0 25 V = +1V G mA/div) 3354 -IQ e (mV) --01..50 Input Bias Current 2105 Input Bias Quiescent Current ( 33333211 +IQ Input Offset Voltag ---122...505 Input Offset Voltage 1500 m and Offset Current ( Input Offset Current A ) 29 -3.0 -5 0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0 -50 -25 0 25 50 75 100 125 Gain Control Voltage (V) Temperature (°C) Figure9.SupplyCurrentvsControlVoltage(A =40dB) Figure10.TypicalDCDriftvsTemperature VMAX 10 SubmitDocumentationFeedback Copyright©2007–2015,TexasInstrumentsIncorporated ProductFolderLinks:VCA820

VCA820 www.ti.com SBOS395D–OCTOBER2007–REVISEDSEPTEMBER2015 7.8 Typical Characteristics: V = ±5 V, A = 6 dB S VMAX AtT =+25°C,R =100Ω,R =1.33kΩ,R =1.33kΩ,V =+2V,V =single-endedinputon+V with–V atground,and A L F G G IN IN IN SO-14package,unlessotherwisenoted. 3 3 0 0 V = 1V O PP B) -3 B) -3 d d n ( VG= +2V n ( ai -6 ai -6 G G d d VO= 2VPP malize -9 malize -9 VO= 5VPP or-12 or-12 N N -15 VAVM=AX 1=V 6dB VG= +1V -15 VO= 7VPP IN PP -18 RL= 100W -18 AVMAX= 6dB 1M 10M 100M 1G 1M 10M 100M 1G Frequency (Hz) Frequency (Hz) Figure11.Small-SignalFrequencyResponse Figure12.Large-SignalFrequencyResponse 300 3 200 2 100 1 mV) V) V(OUT 0 V(OUT 0 -100 -1 -200 -2 V = 250mV V = 2.5V IN PP IN PP f = 20MHz f = 20MHz -300 -3 Time (10ns/div) Time (10ns/div) Figure13.Small-SignalPulseResponse Figure14.Large-SignalPulseResponse 0 0 0 0 -dP, V = +1V A = 6dB -0.05 G -0.02 --00..0150 VMVAGX= +2V --00..0150 Dev Differential Gain (%) ----0000....11220505 -dG, VG= +2V -dP-,d VGG, V= G+2=V +1V ----0000....00014680 Differential Phase ()°Magnitude (dB) -------0000000.......12233445050505 -------0000000.......12233445050505 iation from Linear Phase ()° -0.30 -0.12 -0.50 -0.50 1 2 3 4 0 10 20 30 40 50 Video Loads Frequency (MHz) Figure15.VideoDifferentialGainandDifferentialPhase Figure16.GainFlatness,DeviationFromLinearPhase Copyright©2007–2015,TexasInstrumentsIncorporated SubmitDocumentationFeedback 11 ProductFolderLinks:VCA820

VCA820 SBOS395D–OCTOBER2007–REVISEDSEPTEMBER2015 www.ti.com Typical Characteristics: V = ±5 V, A = 6 dB (continued) S VMAX AtT =+25°C,R =100Ω,R =1.33kΩ,R =1.33kΩ,V =+2V,V =single-endedinputon+V with–V atground,and A L F G G IN IN IN SO-14package,unlessotherwisenoted. -45 -60 -50 VG= +2V A = 6dB 2nd-Harmonic n (dBc) --5650 VRVOLM==A X120V0PWP 2nd-Harmonic n (dBc) -65 stortio --6750 stortio -70 Di 3rd-Harmonic Di c -75 c -75 ni ni Harmo --8805 Harmo -80 VAG= +2=V 6dB 3rd-Harmonic VMAX -90 VO= 2VPP f = 20MHz -95 -85 0.1 1 10 100 100 1k Frequency (MHz) Resistance (W) Figure17.HarmonicDistortionvsFrequency Figure18.HarmonicDistortionvsLoadResistance -50 -40 V = +2V V = 2V G O PP dBc) -55 ARf =VL M=2A0 X1M0=H0 6WzdB dBc) -45 AVRfM =LA X=2 =01 M060dHWBz n ( -60 n ( -50 o o storti -65 storti -55 Maximum Current Through RGLimited Di Di c 2nd-Harmonic 3rd-Harmonic c oni -70 oni -60 m m ar ar 2nd-Harmonic H -75 H -65 3rd-Harmonic -80 -70 0.1 1 10 0.8 1.0 1.2 1.4 1.6 1.8 2.0 Output Voltage Swing (V ) Gain Control Voltage (V) PP Figure19.HarmonicDistortionvsOutputVoltage Figure20.20-MHzHarmonicDistortionvsGainControl Voltage 45 40 Constant Output Voltage 38 40 36 m) m) B B 34 Point (+d 35 Point (+d 3320 Constant Input Voltage Intercept 3205 Intercept 222864 f = 20MHz At 50ΩMatched Load 22 At 50WMatched Load 20 20 0 10 20 30 40 50 60 70 0.8 1.0 1.2 1.4 1.6 1.8 2.0 Frequency (MHz) Gain Control Voltage (V) Figure21.2-Tone,3rd-OrderIntermodulationIntercept Figure22.2-Tone,3rd-OrderIntermodulationInterceptvs GainControlVoltage 12 SubmitDocumentationFeedback Copyright©2007–2015,TexasInstrumentsIncorporated ProductFolderLinks:VCA820

VCA820 www.ti.com SBOS395D–OCTOBER2007–REVISEDSEPTEMBER2015 Typical Characteristics: V = ±5 V, A = 6 dB (continued) S VMAX AtT =+25°C,R =100Ω,R =1.33kΩ,R =1.33kΩ,V =+2V,V =single-endedinputon+V with–V atground,and A L F G G IN IN IN SO-14package,unlessotherwisenoted. 2.2 3 2.0 1.8 0 1.6 B) V/V) 11..42 Gain (d -3 Gain ( 10..08 alized -6 0.6 m 0.4 Nor -9 0.2 0 V = 1V + 10mV G DC PP -0.2 -12 0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0 1M 10M 100M 1G Gain Control Voltage (V) Frequency (Hz) Figure23.GainvsGainControlVoltage Figure24.FrequencyResponse 2.5 10 2.0 0 V = 2V 1.5 V -10 G O 1.0 UT B) -20 0.5 (V) n (d -30 0 ai G -40 (V)N 2211....5050 -0.5 Normalized ---567000 VG= 0V VI 0.5 -80 0 -90 V = 2V -0.5 -100 O PP Time (10ns/div) 1M 10M 100M 1G Frequency (Hz) Figure25.GainControlPulseResponse Figure26.Fully-AttenuatedResponse 12 2.5 1MHz 10 2.0 s) 8 s) n n ay ( 10MHz ay ( 1.5 el 6 el D D up up 1.0 Gro 4 Gro 0.5 2 V = +2V G 20MHz V = 1V O PP 0 0 0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0 0 20 40 60 80 100 Gain Control Voltage (V) Frequency (MHz) Figure27.GroupDelayvsGainControlVoltage Figure28.GroupDelayvsFrequency Copyright©2007–2015,TexasInstrumentsIncorporated SubmitDocumentationFeedback 13 ProductFolderLinks:VCA820

VCA820 SBOS395D–OCTOBER2007–REVISEDSEPTEMBER2015 www.ti.com Typical Characteristics: V = ±5 V, A = 6 dB (continued) S VMAX AtT =+25°C,R =100Ω,R =1.33kΩ,R =1.33kΩ,V =+2V,V =single-endedinputon+V with–V atground,and A L F G G IN IN IN SO-14package,unlessotherwisenoted. 100 d (dB) 96 VO= 0.5VPP CL= 22pF CL= 10pF a o L ve 3 citi CL= 47pF a W) ap 0 R(S 10 n to C -3 CL= 100pF malized Gai --96 VIN 1.33kW +-VVIVINNCA820 RF RS 20W 1kW(1) VOUT 0.1dB Flatness Targeted or NOTE: (1) 1kWis optional. 0 N -12 1 10 100 1k 1M 10M 100M 1G Capacitive Load (pF) Frequency (Hz) Figure29.RecommendedR vsCapacitiveLoad Figure30.FrequencyResponsevsCapacitiveLoad S 1000 10 Öage Noise Density (nV/)Hz 100 VG= V0GV= +2V VG= +1V √ent Noise Density (pA/Hz utput Volt nput Curr O I 10 1 100 1k 10k 100k 1M 10M 100 1k 10k 100k 1M 10M Frequency (Hz) Frequency (Hz) Figure31.OutputVoltageNoiseDensity Figure32.InputCurrentNoiseDensity 14 SubmitDocumentationFeedback Copyright©2007–2015,TexasInstrumentsIncorporated ProductFolderLinks:VCA820

VCA820 www.ti.com SBOS395D–OCTOBER2007–REVISEDSEPTEMBER2015 7.9 Typical Characteristics: V = ±5 V, A = 20 dB S VMAX AtT =+25°C,R =100Ω,R =1kΩ,R =200Ω,V =+2V,andV =single-endedinputon+V with–V atground, A L F G G IN IN IN unlessotherwisenoted. 300 3 V = 50mV V = 0.5V IN PP IN PP f = 20MHz f = 20MHz 200 2 100 1 mV) V) V(OUT 0 V(OUT 0 -100 -1 -200 -2 -300 -3 Time (10ns/div) Time (10ns/div) Figure33.Small-SignalPulseResponse Figure34.Large-SignalPulseResponse 0.05 0.08 1000 )z H 0 0.06 D Ö Magnitude (dB) ------000000......011223505050 VAGVM=A X+2=V 20dB 000---000..00...24642 eviation From Linear Phase ()° Output Voltage Noise Density (nV/ 100 VVGG== + +12VV VG= 0V -0.35 -0.8 10 0 10 20 30 40 50 100 1k 10k 100k 1M 10M Frequency (MHz) Frequency (Hz) Figure35.GainFlatness,DeviationFromLinearPhase Figure36.OutputVoltageNoiseDensity -45 -60 V = +2V -50 AG = 20dB 2nd-Harmonic VMAX -65 -55 RVO== 120V0PWP Bc) L d Gain (dB) ---667050 2nd-Harmonic3rd-Harmonic onic Distortion ( ---778050 3rd-Harmonic -75 Harm -85 VAGVM=A X+2=V 20dB -80 VO= 2VPP f = 20MHz -85 -90 0.1 1 10 100 100 1k Frequency (MHz) Resistance (W) Figure37.HarmonicDistortionvsFrequency Figure38.HarmonicDistortionvsLoadResistance Copyright©2007–2015,TexasInstrumentsIncorporated SubmitDocumentationFeedback 15 ProductFolderLinks:VCA820

VCA820 SBOS395D–OCTOBER2007–REVISEDSEPTEMBER2015 www.ti.com Typical Characteristics: V = ±5 V, A = 20 dB (continued) S VMAX AtT =+25°C,R =100Ω,R =1kΩ,R =200Ω,V =+2V,andV =single-endedinputon+V with–V atground, A L F G G IN IN IN unlessotherwisenoted. -55 -40 V = 2V O PP Bc) -60 Bc) -45 AVMRALX== 12000dWB n (d 2nd-Harmonic n (d -50 f = 20MHz stortio -65 stortio -55 Maximum Current Through RGLimited Di Di c -70 c oni oni -60 m V = +2V 3rd-Harmonic m Har -75 ARGVM=A X10=0 2W0dB Har -65 2nd-Harmonic L f = 20MHz 3rd-Harmonic -80 -70 0.1 1 10 0.8 1.0 1.2 1.4 1.6 1.8 2.0 Output Voltage Swing (V ) Gain Control Voltage (V) PP Figure39.HarmonicDistortionvsOutputVoltage Figure40.20-MHzHarmonicDistortionvsGainControl Voltage 45 40 Constant 38 Output Voltage 40 36 m) m) B B 34 d d nt (+ 35 nt (+ 32 oi oi 30 pt P 30 pt P 28 Constant Input Voltage e e c c er er 26 nt nt I 25 I 24 f = 20MHz At 50WMatched Load 22 At 50WMatched Load 20 20 5 10 15 20 25 30 35 40 45 50 55 60 65 70 0.8 1.0 1.2 1.4 1.6 1.8 2.0 Frequency (MHz) Gain Control Voltage (V) Figure41.2-Tone,3rd-OrderIntermodulationIntercept Figure42.2-Tone,3rd-OrderIntermodulationInterceptvs (G =+10V/V) GainControlVoltage(f =20MHz) MAX IN 11 3 10 9 0 8 B) V) 76 ain (d -3 V/ G n ( 5 ed Gai 4 aliz -6 3 m or 2 N -9 1 0 V = 1V + 10mV G DC PP -1 -12 0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0 1M 10M 100M 1G Gain Control Voltage (V) Frequency (Hz) Figure43.GainvsGainControlVoltage Figure44.GainControlFrequencyResponse 16 SubmitDocumentationFeedback Copyright©2007–2015,TexasInstrumentsIncorporated ProductFolderLinks:VCA820

VCA820 www.ti.com SBOS395D–OCTOBER2007–REVISEDSEPTEMBER2015 Typical Characteristics: V = ±5 V, A = 20 dB (continued) S VMAX AtT =+25°C,R =100Ω,R =1kΩ,R =200Ω,V =+2V,andV =single-endedinputon+V with–V atground, A L F G G IN IN IN unlessotherwisenoted. 2.5 5 2.0 4 1.5 V 100W 2.5 100-0..05.5OUT(V) Voltage (V) 3210 Power 1DWis sInipteartinoanl LoaLdo aL2di5n WLeine50W 2.0 put -1 Load Line V) 1.5 Out -2 1PWow Ienrt eDrnisaslipation ( 1.0 VG0.5 -3 0 -4 -0.5 -5 Time (10ns/div) -300 -200 -100 0 100 200 300 Output Current (mA) Figure45.GainControlPulseResponse Figure46.OutputVoltageandCurrentLimitations 30 2.0 8 A = 20dB 2100 VG= +2V 1.5 InpLuet fVt oSltcaaglee VMVAGX=-0.3V 6 B) 1.0 4 d 0 alized Gain ( ---123000 VO= 2VPP V(V)IN -00..550 02-2 OUTV(V) m or -40 Output Voltage N -50 V = 0V -1.0 Right Scale -4 -60 G -1.5 -6 -70 -2.0 -8 1M 10M 100M 1G Time (40ns/div) Frequency (Hz) Figure47.Fully-AttenuatedResponse Figure48.I LimitedOverdriveRecovery RG 2.0 8 12 A = 20dB Output Voltage VMAX 1MHz 1.5 Right Scale VG= +1V 6 10 1.0 4 put Voltage (V) -00..550 InpLuet fVt oSltcaaglee 20-2 OUTV(V) Group Delay (ns) 864 10MHz n I -1.0 -4 2 -1.5 -6 20MHz -2.0 -8 0 Time (40ns/div) 0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0 Gain Control Voltage (V) Figure49.OutputLimitedOverdriveRecovery Figure50.GroupDelayvsGainControlVoltage Copyright©2007–2015,TexasInstrumentsIncorporated SubmitDocumentationFeedback 17 ProductFolderLinks:VCA820

VCA820 SBOS395D–OCTOBER2007–REVISEDSEPTEMBER2015 www.ti.com Typical Characteristics: V = ±5 V, A = 20 dB (continued) S VMAX AtT =+25°C,R =100Ω,R =1kΩ,R =200Ω,V =+2V,andV =single-endedinputon+V with–V atground, A L F G G IN IN IN unlessotherwisenoted. 3.0 2.5 s) 2.0 n y ( a el 1.5 D p u Gro 1.0 0.5 V = +2V G V = 1V 0 O PP 0 20 40 60 80 100 Frequency (MHz) Figure51.GroupDelayvsFrequency 18 SubmitDocumentationFeedback Copyright©2007–2015,TexasInstrumentsIncorporated ProductFolderLinks:VCA820

VCA820 www.ti.com SBOS395D–OCTOBER2007–REVISEDSEPTEMBER2015 7.10 Typical Characteristics: V = ±5 V, A = 40 dB S VMAX AtT =+25°C,R =100Ω,R =845Ω,R =16.9Ω,V =+2V,V =single-endedinputon+V with–V atground,and A L F G G IN IN IN SO-14package,unlessotherwisenoted. 3 3 V = +2V G 0 0 V = 2V B) -3 -3 O PP d Gain ( -6 VG= +1V dB) -6 zed -9 ain ( -9 VO= 5VPP ormali-12 G-12 VO= 7VPP N V = 20mV IN PP -15 A = 40dB -15 VMAX R = 100W -18 L -18 1M 10M 100M 500M 0 50 100 150 200 250 300 Frequency (Hz) Frequency (MHz) Figure52.Small-SignalFrequencyResponse Figure53.Large-SignalFrequencyResponse 300 3 V = 5mV V = 50mV IN PP IN PP f = 20MHz f = 20MHz 200 2 100 1 mV) (V) (UT 0 OUT 0 O V V -100 -1 -200 -2 -300 -3 Time (10ns/div) Time (10ns/div) Figure54.Small-SignalPulseResponse Figure55.Large-SignalPulseResponse 0.10 0.1 1000 VG= +1V )Hz V = +2V Magnitude (dB) ----00000.....00112550500 AVMAX= 40dB 0-----00000.....12345 Deviation from Linear Pha Öoltage Noise Density (nV/ 100 VG= +1V VG= 0V s V G -0.25 -0.6 e ()° utput O -0.30 -0.7 10 0 10 20 30 40 50 100 1k 10k 100k 1M 10M Frequency (MHz) Frequency (Hz) Figure56.GainFlatness Figure57.OutputVoltageNoiseDensity Copyright©2007–2015,TexasInstrumentsIncorporated SubmitDocumentationFeedback 19 ProductFolderLinks:VCA820

VCA820 SBOS395D–OCTOBER2007–REVISEDSEPTEMBER2015 www.ti.com Typical Characteristics: V = ±5 V, A = 40 dB (continued) S VMAX AtT =+25°C,R =100Ω,R =845Ω,R =16.9Ω,V =+2V,V =single-endedinputon+V with–V atground,and A L F G G IN IN IN SO-14package,unlessotherwisenoted. -35 -40 V = +2V 2nd-Harmonic -40 AG = 40dB -45 VMAX c) -45 VO= 2VPP c) -50 n (dB -50 RL= 100W n (dB -55 3rd-Harmonic stortio -55 2nd-Harmonic stortio --6605 Di -60 Di c c -70 moni -65 moni -75 Har -70 3rd-Harmonic Har -80 VAGVM=A X+2=V 40dB -75 -85 VO= 2VPP f = 20MHz -80 -90 0.1 1 10 100 100 1k Frequency (MHz) Resistance (W) Figure58.HarmonicDistortionvsFrequency Figure59.HarmonicDistortionvsLoadResistance -40 -35 2nd-Harmonic 2nd-Harmonic c) -45 c) -40 B B d d n ( n ( -45 ortio -50 ortio c Dist -55 3rd-Harmonic c Dist -50 Maximum Current Through RGLimited oni oni -55 Harm -60 VARGVLM==A X1+02=0V 4W0dB Harm -60 VAROVLM==A X120V=0 P4WP0dB 3rd-Harmonic f = 20MHz f = 20MHz -65 -65 0.1 1 10 0.8 1.0 1.2 1.4 1.6 1.8 2.0 Output Voltage Swing (V ) Gain Control Voltage (V) PP Figure60.HarmonicDistortionvsOutputVoltage Figure61.20-MHzHarmonicDistortionvsGainControl Voltage 33 35 31 30 Intercept Point (+dBm) 222221975319 Intercept Point (+dBm) 22115050 Constant Output Voltage Constant Input Voltage 17 5 f = 20MHz At 50WMatched Load At 50WMatched Load 15 0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 0.8 1.0 1.2 1.4 1.6 1.8 2.0 Frequency (MHz) Gain Control Voltage (V) Figure62.2-Tone,3rd-OrderIntermodulationIntercept Figure63.2-Tone,3rd-OrderIntermodulationInterceptvs GainControlVoltage(f =20MHz) IN 20 SubmitDocumentationFeedback Copyright©2007–2015,TexasInstrumentsIncorporated ProductFolderLinks:VCA820

VCA820 www.ti.com SBOS395D–OCTOBER2007–REVISEDSEPTEMBER2015 Typical Characteristics: V = ±5 V, A = 40 dB (continued) S VMAX AtT =+25°C,R =100Ω,R =845Ω,R =16.9Ω,V =+2V,V =single-endedinputon+V with–V atground,and A L F G G IN IN IN SO-14package,unlessotherwisenoted. 110 3 100 90 0 80 B) V/V) 7600 Gain (d -3 Gain ( 5400 alized -6 30 m 20 Nor -9 10 V = 10mV IN DC 0 V = 1V + 10mV G DC PP -10 -12 0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0 1M 10M 100M 1G Gain Control Voltage (V) Frequency (Hz) Figure64.GainvsGainControlVoltage Figure65.GainControlFrequency 2.5 50 2.0 40 1.5 OV 30 VG= +2V 1.0 UT B) 0.5 (V) n (d 20 0 ai 10 G 2.5 -0.5 d 0 e 2.0 aliz -10 (V)N 11..50 Norm -20 Input-Referred VI 0.50 --3400 VO= 2VPP VG= 0V -0.5 -50 Time (10ns/div) 1M 10M 100M 1G Frequency (Hz) Figure66.GainControlPulseResponse Figure67.Fully-AttenuatedResponse 0.3 6 0.20 8 Input Voltage A = 40dB 0.2 Left Scale ORiugthptu St cVaolletage 4 0.15 ORiugthptu St cVaolletage VMAVXG= +2V 6 0.10 4 Input Voltage (V) -00..101 20-2 Output Voltage (V) Input Voltage (mV) --000...0015500 InpLuet fVt oSltcaaglee 20--86 Output Voltage (V) -0.2 AVMAX= 40dB -4 -0.15 -4 V = 0.85V G -0.3 -6 -0.20 -2 Time (40ns/div) Time (40ns/div) Figure68.InputLimitedOverdriveRecovery Figure69.OutputLimitedOverdriveRecovery Copyright©2007–2015,TexasInstrumentsIncorporated SubmitDocumentationFeedback 21 ProductFolderLinks:VCA820

VCA820 SBOS395D–OCTOBER2007–REVISEDSEPTEMBER2015 www.ti.com Typical Characteristics: V = ±5 V, A = 40 dB (continued) S VMAX AtT =+25°C,R =100Ω,R =845Ω,R =16.9Ω,V =+2V,V =single-endedinputon+V with–V atground,and A L F G G IN IN IN SO-14package,unlessotherwisenoted. 14 4.0 12 3.5 1MHz 3.0 s) 10 s) ay (n 8 ay (n 2.5 Del 10MHz Del 2.0 p 6 p ou ou 1.5 Gr Gr 4 1.0 2 0.5 VG= +2V 20MHz V = 1V O PP 0 0 0 0.2 0.4 0.6 0.8 1.0 0 20 40 60 80 100 Gain Control Voltage (V) Frequency (MHz) Figure70.GroupDelayvsGainControlVoltage Figure71.GroupDelayvsFrequency 22 SubmitDocumentationFeedback Copyright©2007–2015,TexasInstrumentsIncorporated ProductFolderLinks:VCA820

VCA820 www.ti.com SBOS395D–OCTOBER2007–REVISEDSEPTEMBER2015 8 Detailed Description 8.1 Overview The VCA820 is a voltage controlled variable gain amplifier with differential inputs and a single ended output. The maximum gain is set by external resistors while the gain range is controlled by an external analog voltage. The maximum gain is designed for gains of 2 V/V up to 100 V/V and the analog control allows a gain range of over 40 dB. The VCA820 Input consists of two buffers which, together create a fully symmetrical, high impedance differential input with a typical common mode rejection of 80 dB. The gain set resistor is connected between the two input buffer output pins, so that the input impedance is independent of the gain settings. The bipolar inputs have a input voltage range of +1.6 and –2.1 V on ±5-V supplies. The amplifier maximum gain is set by external resistors, but the internal gain control circuit is controlled by a continuously variable, analog voltage. The gain control is a multiplier stage which is linear in dB. The gain control input pin operates over a voltage range of 0 V to 2 V. The VCA820 contains a high-speed, high-current output buffer. The output stage can typically swing ±3.9 Vandsourceandsink±160mA.TheVCA820canbeoperatedoveravoltagerangeof ±3.5Vto ±6V. 8.2 Functional Block Diagram V G +V V IN IN 20 x1 FB I R RG G+ R F R 1k G 200 R x2 V G- OUT V OUT x1 -V V VCA820 20 IN REF 20 8.3 Feature Description The VCA820 can be operated with both single ended or differential input signals. The inputs present consistently high impedance across all gain configurations. By using an analog control signal the amplifier gain is continuously variable for smooth, glitch-free gain changes. With a large signal bandwidth of 137 MHz and a slew rate of 1700 V/µs the VCA820 offers linear performance over a wide range of signal amplitudes and gain settings. The low-impedance/high-current output buffer can drive loads ranging from low impedance transmission lines to high-impedance, switched-capacitor analog to digital converters. By using closely matched internal componentstheVCA820offersgainaccuracyof±0.4dB. Copyright©2007–2015,TexasInstrumentsIncorporated SubmitDocumentationFeedback 23 ProductFolderLinks:VCA820

VCA820 SBOS395D–OCTOBER2007–REVISEDSEPTEMBER2015 www.ti.com 8.4 Device Functional Modes The VCA820 functions as a differential input, single-ended output variable gain amplifier. This functional mode is enabledbyapplyingpowertotheamplifiersupplypinsandisdisabledbyturningthepoweroff. The gain is continuously variable through the analog gain control input. While the gain range is fixed the maximum gain is set by two external components, Rf and Rg as shown in the Functional Block Diagram. The maximumgainisequalto2x(Rf/Rg).Thisgainisachievedwitha2-VvoltageonthegainadjustpinVG.Asthe voltagedecreasesontheVGpin,thegaindecreasesinalinearindBfashionwithover40dBofgainrangefrom 2-Vto0-Vcontrolvoltage. As with most other differential input amplifiers, inputs can be applied to either one or both of the amplifier inputs. Theamplifiergainiscontrolledthroughthegaincontrolpin. 8.4.1 MaximumGainofOperation ThissectiondescribestheuseoftheVCA820inafixed-gainapplicationinwhichtheV controlpinissetatV = G G +2V.Thetradeoffsdescribedherearewithbandwidth,gain,andoutputvoltagerange. In the case of an application that does not make use of the V , but requires some other characteristic of the GAIN VCA820, the R resistor must be set such that the maximum current flowing through the resistance I is less G RG than ±2.6-mA typical, or 5.2 mA as defined in the Electrical Characteristics: V = ±5 V table, and must follow PP S Equation1. V OUT I = RG A ´R VMAX G (1) As illustrated in Equation 1, once the output dynamic range and maximum gain are defined, the gain resistor is set. This gain setting in turn affects the bandwidth, because in order to achieve the gain (and with a set gain element), the feedback element of the output stage amplifier is set as well. Keeping in mind that the output amplifieroftheVCA820isacurrent-feedbackamplifier,thelargerthefeedbackelement,thelowerthebandwidth asthefeedbackresistoristhecompensationelement. Limiting the discussion to the input voltage only and ignoring the output voltage and gain, Figure 1 illustrates the tradeoffbetweentheinputvoltageandthecurrentflowingthroughthegainresistor. 8.4.2 OutputCurrentandVoltage The VCA820 provides output voltage and current capabilities that are unsurpassed in a low-cost monolithic VCA. Under no-load conditions at +25°C, the output voltage typically swings closer than 1 V to either supply rails; the +25°C swing limit is within 1.2 V of either rails. Into a 15-Ω load (the minimum tested load), it is tested to deliver morethan±160mA. The specifications described above, though familiar in the industry, consider voltage and current limits separately. In many applications, it is the voltage × current, or V-I product, that is more relevant to circuit operation.RefertotheOutputVoltageandCurrentLimitations plot(Figure46)intheTypicalCharacteristics.The X- and Y-axes of this graph show the zero-voltage output current limit and the zero-current output voltage limit, respectively. The four quadrants give a more detailed view of the VCA820 output drive capabilities, noting that the graph is bounded by a Safe Operating Area of 1W maximum internal power dissipation. Superimposing resistor load lines onto the plot shows that the VCA820 can drive ±2.5 V into 25 Ω or ±3.5 V into 50 Ω without exceeding the output capabilities or the 1-W dissipation limit. A 100-Ω load line (the standard test circuit load) showsthefull±3.9-Voutputswingcapability,asshownintheTypicalCharacteristics. The minimum specified output voltage and current over-temperature are set by worst-case simulations at the coldtemperatureextreme.Onlyatcoldstartupdotheoutputcurrentandvoltagedecreasetothenumbersshown in the Electrical Characteristics tables. As the output transistors deliver power, the respective junction temperaturesincrease,increasingtheavailableoutputvoltageswing,andincreasingtheavailableoutputcurrent. In steady-state operation, the available output voltage and current is always greater than that temperature shown in the over-temperature specifications because the output stage junction temperatures are higher than the specifiedoperatingambient. 24 SubmitDocumentationFeedback Copyright©2007–2015,TexasInstrumentsIncorporated ProductFolderLinks:VCA820

VCA820 www.ti.com SBOS395D–OCTOBER2007–REVISEDSEPTEMBER2015 Device Functional Modes (continued) 8.4.3 InputVoltageDynamicRange TheVCA820hasainputdynamicrangelimitedto+1.6Vand –2.1V.Increasingtheinputvoltagedynamicrange can be done by using an attenuator network on the input. If the VCA820 is trying to regulate the amplitude at the output,suchasinanAGCapplication,theinputvoltagedynamicrangeisdirectlyproportionaltoEquation2. V = R ´I IN(PP) G RG(PP) (2) As such, for unity-gain or under-attenuated conditions, the input voltage must be limited to the CMIR of ±1.6 V (3.2 V ) and the current (I ) must flow through the gain resistor, ±2.6 mA (5.2 mA ). This configuration sets a PP RQ PP minimumvalueforR suchthatthegainresistorhastobegreaterthanEquation3. E 3.2V R = PP = 615.4W GMIN 5.2mA PP (3) Values lower than 615.4Ω are gain elements that result in reduced input range, as the dynamic input range is limited by the current flowing through the gain resistor R (I ). If the I current is limiting the performance of G RG RG the circuit, the input stage of the VCA820 goes into overdrive, resulting in limited output voltage range. Such I - RG limitedoverdriveconditionsareshowninFigure48forthegainof20dBandFigure68 forthe40-dBgain. 8.4.4 OutputVoltageDynamicRange With its large output current capability and its wide output voltage swing of ±3.9-V typical on 100-Ω load, it is easy to forget other types of limitations that the VCA820 can encounter. For these limitations, careful analysis must be done to avoid input stage limitation, either voltage or I current; also, consider the gain limitation, as RG thecontrolpinV varies,affectingotheraspectsofthecircuit. G 8.4.5 Bandwidth The output stage of the VCA820 is a wideband current-feedback amplifier. As such, the external feedback resistance is the compensation of the last stage. Reducing the feedback element and maintaining the gain constant limits the useful range of I , and therefore reducing the gain adjust range. For a given gain, reducing RG thegainelementlimitsthemaximumachievableoutputvoltageswing. 8.4.6 OffsetAdjustment As a result of the internal architecture used on the VCA820, the output offset voltage originates from the output stage and from the input stage and multiplier core. Figure 87 illustrates how to compensate both sources of the output offset voltage. Use this procedure to compensate the output offset voltage: starting with the output stage compensation, set V = 0 V to eliminate all offset contribution of the input stage and multiplier core. Adjust the G output stage offset compensation potentiometer. Finally, set V = +1 V to the maximum gain and adjust the input G stage and multiplier core potentiometer. This procedure effectively eliminates all offset contribution at the maximum gain. Because adjusting the gain modifies the contribution of the input stage and the multiplier core, someresidualoutputoffsetvoltageremains. 8.4.7 Noise The VCA820 offers 8.2-nV/√Hz input-referred voltage noise density at a gain of 20 dB and 1.8-pA/√Hz input- referred current noise density. The input-referred voltage noise density considers that all noise terms, except the inputcurrentnoiseoneachofthetwoinputpinsbutincludingthethermalnoiseofboththefeedbackresistorand thegainresistor,areexpressedasoneterm. ThismodelisformulatedinEquation4andFigure86. e = A ´ 2´(R ´i )2+ e 2+ 2´4kTR O VMAX S n n S (4) A more complete model is illustrated in Figure 88. For additional information on this model and the actual modelednoiseterms,pleasecontacttheHigh-SpeedProductApplicationSupportteamatwww.ti.com. Copyright©2007–2015,TexasInstrumentsIncorporated SubmitDocumentationFeedback 25 ProductFolderLinks:VCA820

VCA820 SBOS395D–OCTOBER2007–REVISEDSEPTEMBER2015 www.ti.com Device Functional Modes (continued) 8.4.8 InputandESDProtection The VCA820 is built using a very high-speed complementary bipolar process. The internal junction breakdown voltagesarerelativelylowfortheseverysmallgeometrydevices.Thesebreakdownsarereflectedinthetable. All pins on the VCA820 are internally protected from ESD by means of a pair of back-to-back reverse-biased diodes to either power supply, as shown in Figure 72. These diodes begin to conduct when the pin voltage exceeds either power supply by approximately 0.7 V. This situation can occur with loss of the amplifier power supplies while a signal source is still present. The diodes can typically withstand a continuous current of 30 mA without destruction. To ensure long-term reliability, however, diode current should be externally limited to 10 mA wheneverpossible. ESD Protection diodes internally +VS connected to all pins. External Internal Pin Circuitry -V S Figure72. InternalESDProtection 26 SubmitDocumentationFeedback Copyright©2007–2015,TexasInstrumentsIncorporated ProductFolderLinks:VCA820

VCA820 www.ti.com SBOS395D–OCTOBER2007–REVISEDSEPTEMBER2015 9 Application and Implementation NOTE Information in the following applications sections is not part of the TI component specification, and TI does not warrant its accuracy or completeness. TI’s customers are responsible for determining suitability of components for their purposes. Customers should validateandtesttheirdesignimplementationtoconfirmsystemfunctionality. 9.1 Application Information The VCA820 has flexible maximum gain which is set by the Rf and Rg resistors shown in Functional Block Diagram. The maximum gain is equal to 2x (Rf / Rg). This gain is achieved with a 2-V voltage on the gain adjust pin VG. As the voltage decreases on the VG pin, the gain decreases in a linear in dB fashion with over 40 dB of gainrangefrom2-Vto0-Vcontrolvoltage. 9.1.1 Design-InTools 9.1.1.1 DemonstrationBoards Two printed circuit boards (PCBs) are available to assist in the initial evaluation of circuit performance using the VCA820 in its two package options. Both of these are offered free of charge as unpopulated PCBs, delivered withauser'sguide.ThesummaryinformationforthesefixturesisshowninTable2. Table2.EVMOrderingInformation PRODUCT PACKAGE BOARDPARTNUMBER LITERATUREREQUESTNUMBER VCA820ID SO-14 DEM-VCA-SO-1B SBOU050 VCA820IDGS MSOP-10 DEM-VCA-MSOP-1A SBOU051 The demonstration fixtures can be requested at the Texas Instruments web site (www.ti.com) through the VCA820productfolder. 9.1.1.2 MacromodelsandApplicationsSupport Computer simulation of circuit performance using SPICE is often useful when analyzing the performance of analog circuits and systems. This principle is particularly true for video and RF amplifier circuits where parasitic capacitance and inductance can play a major role in circuit performance. A SPICE model for the VCA820 is available through the TI web page. The applications group is also available for design assistance. The models available from TI predict typical small-signal ac performance, transient steps, dc performance, and noise under a wide variety of operating conditions. The models include the noise terms found in the electrical specifications of therelevantproductdatasheet. 9.1.2 OperatingSuggestions Operating the VCA820 optimally for a specific application requires trade-offs between bandwidth, input dynamic range and the maximum input voltage, the maximum gain of operation and gain, output dynamic range and the maximum input voltage, the package used, loading, and layout and bypass recommendations. The Typical Characteristics have been defined to cover a wide range of external and operating conditions to describe the VCA820operation.TherearefoursectionsintheTypicalCharacteristics: • V =±5VDCParametersandV =±5VDCandPower-SupplyParameters,whichincludeDCoperationand S S theintrinsiclimitationofaVCA820design • V =±5V,A =6dBGainof6-dBOperation S VMAX • V =±5V,A =20dBGainof20-dBOperation S VMAX • V =±5V,A =40dBGainof40-dBOperation S VMAX Where the Typical Characteristics describe the actual performance that can be achieved by using the amplifier properly,thefollowingsectionsdescribeindetailthetrade-offsneededtoachievethislevelofperformance. Copyright©2007–2015,TexasInstrumentsIncorporated SubmitDocumentationFeedback 27 ProductFolderLinks:VCA820

VCA820 SBOS395D–OCTOBER2007–REVISEDSEPTEMBER2015 www.ti.com Application Information (continued) 9.1.2.1 PackageConsiderations The VCA820 is available in both SO-14 and MSOP-10 packages. Each package has, for the different gains used in the typical characteristics, different values of R and R in order to achieve the same performance detailed in F G theElectricalCharacteristicstable. Figure 73 shows a test gain circuit for the VCA820. Table 3 lists the recommended configuration for the SO-14 andMSOP-10package. +V V IN R IN F R 50W 1 RG+ Source 50W R V G OUT R G- 50W R Load 3 -V R IN 2 50W V G Figure73. TestCircuit Table3.SO-14andMSOP-10R andR Configurations F G G=2 G=10 G=100 R 1.33kΩ 1kΩ 845Ω F R 1.33kΩ 200Ω 16.9Ω G There are no differences between the packages in the recommended values for the gain and feedback resistors. However, the bandwidth for the VCA820IDGS (MSOP-10 package) is lower than the bandwidth for the VCA820ID (SO-14 package). This difference is true for all gains, but especially true for gains greater than 5 V/V, ascanbeseeninFigure74andFigure75.Thescalemustbechangedtoalinearscaletoviewthedetails. 3 3 0 0 B) AVMAX= 6dB B) AVMAX= 20dB ain (d -3 ain (d -3 AVMAX= 6dB G G malized -6 AVMAAXVM=A X14=d 2B0dB malized -6 AVMAX= 26dB Nor -9 AVMAX= 26dB Nor -9 AVMAX= 34dB AVMAX= 34dB AVMAX= 40dB -12 AVMAX= 40dB -12 AVMAX= 14dB 0 50 100 150 200 0 50 100 150 200 Frequency (MHz) Frequency (MHz) Figure74.SO-14RecommendedR andR vsA Figure75.MSOP-10RecommendedR andR vsA F G VMAX F G VMAX 28 SubmitDocumentationFeedback Copyright©2007–2015,TexasInstrumentsIncorporated ProductFolderLinks:VCA820

VCA820 www.ti.com SBOS395D–OCTOBER2007–REVISEDSEPTEMBER2015 9.2 Typical Applications 9.2.1 WidebandVariableGainAmplifierOperation 0.1µF +5V X2Y@Cap -5V + 2.2µF 2.2µF + V G +V V IN IN 50W x1 FB I R RG G+ R F R 1kW G 200W RG- x2 VOUT V OUT x1 -V V VCA820 50W IN REF 50W Figure76. DC-Coupled,A =20dB,BipolarSupplySpecificationandTestCircuit VMAX 9.2.1.1 DesignRequirements The design shown in Figure 76 supports a single-ended input, continuously variable gain control and a single- ended output. This configuration is used to achieve the best performance with a bipolar supply. This circuit also requiresamaximumgainof10V/Vandlownoise. 9.2.1.2 DetailedDesignProcedure The VCA820 provides an exceptional combination of high output power capability with a wideband, greater than 40-dB gain adjust range, linear in dB variable gain amplifier. The VCA820 input stage places the transconductance element between two input buffers, using the output currents as the forward signal. As the differential input voltage rises, a signal current is generated through the gain element. This current is then mirrored and gained by a factor of two before reaching the multiplier. The other input of the multiplier is the voltage gain control pin, V . Depending on the voltage present on V , up to two times the gain current is G G provided to the transimpedance output stage. The transimpedance output stage is a current-feedback amplifier providing high output current capability and high slew rate, 1700 V/μs. This exceptional full-power performance comes at the price of a relatively high quiescent current (34mA), but a low input voltage noise for this type of architecture(8.2nV/√Hz). Figure 76 shows the dc-coupled, gain of 20 dB, dual power-supply circuit used as the basis of the ±5 V and . For test purposes, the input impedance is set to 50 Ω with a resistor to ground and the output impedance is set to 50 Ω with a series output resistor. Voltage swings reported in the table are taken directly at the input and output pins,whileoutputpower(dBm)isatthematched50-Ωload.ForthecircuitinFigure76,thetotaleffectiveloadis 100 Ω ∥ 1 kΩ. Note that for the SO-14 package, there is a voltage reference pin, V (pin 9). For the SO-14 REF package, this pin must be connected to ground through a 20-Ω resistor in order to avoid possible oscillations of the output stage. In the MSOP-10 package, this pin is internally connected to ground and does not require such precaution. An X2Y® capacitor has been used for power-supply bypassing. The combination of low inductance, high resonance frequency, and integration of three capacitors in one package (two capacitors to ground and one across the supplies) of this capacitor contributes to the low second-harmonic distortion reported in the Electrical Characteristicstable.MoreinformationonhowtheVCA820operatescanbefoundinthesection. Copyright©2007–2015,TexasInstrumentsIncorporated SubmitDocumentationFeedback 29 ProductFolderLinks:VCA820

VCA820 SBOS395D–OCTOBER2007–REVISEDSEPTEMBER2015 www.ti.com 9.2.1.3 ApplicationCurves 3 3 0 0 V = +2V Gain (dB) --36 G Gain (dB) --36 VO= 2VPP malized -9 malized -9 VO= 5VPP Nor -12 A = 20dB Nor -12 V = 7V VMAX O PP -15 VIN= 0.2VPP -15 -18 RL= 100W VG= +1V -18 1M 10M 100M 1G 0 50 100 150 200 250 300 350 400 Frequency (Hz) Frequency (MHz) Figure77.Small-SignalFrequencyResponse Figure78.Large-SignalFrequencyResponse 30 SubmitDocumentationFeedback Copyright©2007–2015,TexasInstrumentsIncorporated ProductFolderLinks:VCA820

VCA820 www.ti.com SBOS395D–OCTOBER2007–REVISEDSEPTEMBER2015 9.2.2 DifferenceAmplifier R F V +V IN+ IN R R G+ FB S RG VCA820 R G- V -V IN- IN 20W R S Figure79. WidebandDifferentialtoSingle-EndedAmplifier 9.2.2.1 DesignRequirements For a difference amplifier, the design requirements are differential voltage gain, common mode rejection, and loaddrivecapability.Thiscircuitdeliversdifferentialgainof2*(Rf/Rg),andCMRRasshowninFigure80. 9.2.2.2 DetailedDesignProcedure Because both inputs of the VCA820 are high-impedance, a difference amplifier can be implemented without any major problem. This implementation is shown in Figure 79. This circuit provides excellent common-mode rejection ratio (CMRR) as long as the input is within the CMRR range of –2.1 V to +1.6 V. Note that this circuit does not make use of the gain control pin, V . Also, it is recommended to choose R such that the pole formed G S by R and the parasitic input capacitance does not limit the bandwidth of the circuit. The common-mode rejection S ratio for this circuit implemented in a gain of 20 dB for V = +2 V is shown in Figure 80. Note that because the G gain control voltage is fixed and is normally set to +2 V, the feedback element can be reduced in order to increase the bandwidth. When reducing the feedback element make sure that the VCA820 is not limited by common-modeinputvoltage,thecurrentflowingthroughR ,oranyotherlimitationdescribedinthisdatasheet. G 9.2.2.3 ApplicationCurve 95 B) 90 d o ( 85 Rati 80 on 75 ecti 70 ej R 65 e od 60 M n- 55 o m 50 m Co 45 Input-Referred 40 100k 1M 10M 100M Frequency (Hz) Figure80.Common-ModeRejectionRatio Copyright©2007–2015,TexasInstrumentsIncorporated SubmitDocumentationFeedback 31 ProductFolderLinks:VCA820

VCA820 SBOS395D–OCTOBER2007–REVISEDSEPTEMBER2015 www.ti.com 9.2.3 DifferentialEqualizer R V +V F IN1 IN R R G+ S R FB 1 RG VCA820 C 1 R G- VIN2 -VIN 20W R S Figure81. DifferentialEqualizer 9.2.3.1 DesignRequirements Signals that travel over a length of cable experience an attenuation that is proportional to the square root of the frequency. For this reason, a flat response amplifier will not restore the original signal. To replicate the original signal, the higher frequency signal components require more gain. The circuit in Figure 81 has one stage of frequency shaping to help restore a signal transmitted along a cable. If needed, additional frequency shaping stagescanbeaddedasshowninFigure82. 9.2.3.2 DetailedDesignProcedure If the application requires frequency shaping (the transition from one gain to another), the VCA820 can be used advantageouslybecauseitsarchitectureallowstheapplicationtoisolatetheinputfromthegainsettingelements. Figure81showsanimplementationofsuchaconfiguration.ThetransferfunctionisshowninEquation5. R 1 + sR C G = 2´ F ´ G 1 R 1 + sR C G 1 1 (5) Thistransferfunctionhasonepole,P (locatedatR C ),andonezero,Z (locatedatR C ).Whenequalizingan 1 G 1 1 1 1 RC load, R and C , compensate the pole added by the load located at R C with the zero Z . Knowing R , C , L L L L 1 L L and R allows the user to select C as a first step and then calculate R . Using R = 75 Ω, C = 100 pF and G 1 1 L L wanting the VCA820 to operate at a gain of +2 V/V, which gives R = R = 1.33 kΩ, allows the user to select C F G 1 = 5 pF to ensure a positive value for the resistor R . With all these values known, R can be calculated to be 170 1 1 Ω. The frequency response for both the initial, unequalized frequency response and the resulting equalized frequencyresponseareillustratedinFigure82. 9.2.3.3 ApplicationCurve 9 Equalized Frequency 6 Response 3 0 -3 dB) -6 Gain ( -9 Inoift iaVlC FAre8q2u0e wncityh RReCs pLoonasde -12 -15 -18 -21 -24 1M 10M 100M 1G Frequency (Hz) Figure82.DifferentialEqualizationofanRCLoad 32 SubmitDocumentationFeedback Copyright©2007–2015,TexasInstrumentsIncorporated ProductFolderLinks:VCA820

VCA820 www.ti.com SBOS395D–OCTOBER2007–REVISEDSEPTEMBER2015 9.2.4 DifferentialCableEqualizer R 2 1.33kW V +V IN IN R8 RG+ R 50W R401k8W R171.75kW R8.271kW R1.927kW R1.333kW VCA820 VFB VOUT 751W0 VOUT C7 REF 100nF GND 75WLoad C6 R-VGIN- VG R201W 120nF R 5 50W C 5 V = +2V 1.42pF G DC C 9 10µF Figure83. DifferentialCableEqualizer 9.2.4.1 DesignRequirements Signals that travel over a length of cable experience an attenuation that is proportional to the square root of the frequency. For this reason, a fixed bandwidth amplifier will not restore the original signal. To replicate the original signal, the higher frequency signal components require more gain. The circuit in Figure 83 has multiple stages of frequency shaping to help restore a signal transmitted along a cable. This circuit is similar to the one shown in Figure81,butismuchmoreaccurateinreplicatingthe1/(sqrt(f))frequencyresponseshape. 9.2.4.2 DetailedDesignProcedure A differential cable equalizer can easily be implemented using the VCA820. An example of a cable equalization for 100 feet of Belden Cable 1694F is illustrated in Figure 83, with the result for this implementation shown in Figure84.Thisimplementationhasamaximumerrorof0.2dBfromdcto40MHz. Notethatthisimplementationshowsthecableattenuationside-by-sidewiththeequalizationinthesameplot.For a given frequency, the equalization function realized with the VCA820 matches the cable attenuation. The circuit in Figure 83 is a driver circuit. To implement a receiver circuit, the signal is received differentially between the +V and–V inputs. IN IN Foradetaileddesignprocedure,refertotoSBOA124. 9.2.4.3 ApplicationCurve 2.0 Cable Attenuations B) 1.5 d on (B) uatin (d 1.0 F Cable AttenEqualizer Gai 0.05 VECqAua8l2iz0a twioitnh 4 9 6 -0.5 1 -1.0 1 10 100 Frequency (MHz) Figure84.CableAttenuationversusEqualizerGain Copyright©2007–2015,TexasInstrumentsIncorporated SubmitDocumentationFeedback 33 ProductFolderLinks:VCA820

VCA820 SBOS395D–OCTOBER2007–REVISEDSEPTEMBER2015 www.ti.com 9.2.5 AGCLoop 1kW V +V IN IN R FB 50W G+ 50W 200W VCA820 Out 50W RG- VG OPA695 VOUT -VIN 50W 950W 100W 50W 0.1mF 1kW 1N4150 OPA820 V REF Figure85. AGCLoop 9.2.5.1 DesignRequirements When dynamic signal amplitude correction is required, an AGC loop will provide real-time gain control. The requirements for this circuit are fast gain control response and linear in dB gain control. The time constant of the loop is set with the 0.1-µF capacitor and the 1-kΩ resistor. The OPA695 provides additional load driving capability. 9.2.5.2 DetailedDesignProcedure In the typical AGC loop shown in Figure 85, the OPA695 follows the VCA820 to provide 40 dB of overall gain. The output of the OPA695 is rectified and integrated by an OPA820 to control the gain of the VCA820. When the output level exceeds the reference voltage (V ), the integrator ramps down reducing the gain of the AGC loop. REF Conversely,iftheoutputistoosmall,theintegratorrampsupincreasingthenetgainandtheoutputvoltage. 34 SubmitDocumentationFeedback Copyright©2007–2015,TexasInstrumentsIncorporated ProductFolderLinks:VCA820

VCA820 www.ti.com SBOS395D–OCTOBER2007–REVISEDSEPTEMBER2015 9.3 System Examples R F +V IN R i R e G+ FB n S i RG VCA820 eO ∗ R 4kTRS -VGI-N i R n S ∗ 4kTRS NOTE: R and R are noiseless. F G Figure86. SimpleNoiseModel +5V Output Stage Offset 10kW Compensation Circuit 0.1mF 4kW -5V R F V +V IN IN R 50W G+ FB RG VCA820 VOUT R G- +5V -VIN 50W 1kW 10kW 0.1mF Input Stage and Multiplexer Core -5V Offset Compensation Circuit Figure87. AdjustingtheInputandOutputVoltageSources Copyright©2007–2015,TexasInstrumentsIncorporated SubmitDocumentationFeedback 35 ProductFolderLinks:VCA820

VCA820 SBOS395D–OCTOBER2007–REVISEDSEPTEMBER2015 www.ti.com V G i V nINPUT G +V IN V+ R S1 * enINPUT * 4kTRS1 FB x1 R F +RG * inINPUT * 4kTRF V OUT R e G O (Noiseless) ICORE iinOUTPUT -RG VREF x1 R F e i nOUTPUT niOUTPUT * enINPUT * 4kTRF -V IN V- RS2 inINPUT GND * 4kTRS2 Figure88. FullNoiseModel 36 SubmitDocumentationFeedback Copyright©2007–2015,TexasInstrumentsIncorporated ProductFolderLinks:VCA820

VCA820 www.ti.com SBOS395D–OCTOBER2007–REVISEDSEPTEMBER2015 10 Power Supply Recommendations High-speed amplifiers require low inductance power supply traces and low ESR bypass capacitors. The power supply voltage should be centered on the desired amplifier output voltage, so for ground referenced output signals,splitsuppliesarerequired.Thepowersupplyvoltageshouldbefrom7Vto12V. 11 Layout 11.1 Layout Guidelines Achievingoptimumperformancewithahigh-frequencyamplifiersuchastheVCA820requirescarefulattentionto printed circuit board (PCB) layout parasitics and external component types. Recommendations to optimize performanceinclude: • Minimize parasitic capacitance to any ac ground for all of the signal I/O pins. This recommendation includes the ground pin (pin 2). Parasitic capacitance on the output can cause instability: on both the inverting input and the noninverting input, it can react with the source impedance to cause unintentional band limiting. To reduceunwantedcapacitance,awindowaroundthesignalI/Opinsshouldbeopenedinallofthegroundand power planes around those pins. Otherwise, ground and power planes should be unbroken elsewhere on the board. Place a small series resistance (greater than 25 Ω) with the input pin connected to ground to help decouplepackageparasitics. • Minimize the distance (less than 0.25”) from the power-supply pins to high-frequency 0.1-μF decoupling capacitors. At the device pins, the ground and power plane layout should not be in close proximity to the signal I/O pins. Avoid narrow power and ground traces to minimize inductance between the pins and the decoupling capacitors. The power-supply connections should always be decoupled with these capacitors. Larger (2.2 μF to 6.8 μF) decoupling capacitors, effective at lower frequencies, should also be used on the main supply pins. These capacitors may be placed somewhat farther from the device and may be shared amongseveraldevicesinthesameareaofthePCB. • Careful selection and placement of external components preserve the high-frequency performance of the VCA820. Resistors should be a very low reactance type. Surface-mount resistors work best and allow a tighter overall layout. Metal-film and carbon composition, axially-leaded resistors can also provide good high- frequency performance. Again, keep the leads and PCB trace length as short as possible. Never use wire- wound type resistors in a high-frequency application. Because the output pin is the most sensitive to parasitic capacitance, always position the series output resistor, if any, as close as possible to the output pin. Other network components, such as inverting or non-inverting input termination resistors, should also be placed closetothepackage. • Connections to other wideband devices on the board may be made with short direct traces or through onboard transmission lines. For short connections, consider the trace and the input to the next device as a lumped capacitive load. Relatively wide traces (50 mils to 100 mils, or 1.27 mm to 2.54 mm) should be used, preferablywithgroundandpowerplanesopeneduparoundthem. • Socketing a high-speed part like the VCA820 is not recommended. The additional lead length and pin-to-pin capacitance introduced by the socket can create an extremely troublesome parasitic network, which can make it almost impossible to achieve a smooth, stable frequency response. Best results are obtained by solderingtheVCA820ontotheboard. Copyright©2007–2015,TexasInstrumentsIncorporated SubmitDocumentationFeedback 37 ProductFolderLinks:VCA820

VCA820 SBOS395D–OCTOBER2007–REVISEDSEPTEMBER2015 www.ti.com 11.2 Layout Example Figure89. VCA820RecommendedLayout 11.3 Thermal Considerations The VCA820 does not require heatsinking or airflow in most applications. The maximum desired junction temperature sets the maximum allowed internal power dissipation as described in this section. In no case should themaximumjunctiontemperaturebeallowedtoexceed+150°C. Operatingjunctiontemperature(T )isgivenbyEquation6: J T = T + P ´q J A D JA (6) The total internal power dissipation (P ) is the sum of quiescent power (P ) and additional power dissipated in D DQ the output stage (P ) to deliver load power. Quiescent power is simply the specified no-load supply current DL times the total supply voltage across the part. P depends on the required output signal and load; for a DL grounded resistive load, however, it is at a maximum when the output is fixed at a voltage equal to one-half of eithersupplyvoltage(forequalbipolarsupplies).Underthisworst-casecondition,P =V 2/(4× R ),whereR is DL S L L theresistiveload. Note that it is the power in the output stage and not in the load that determines internal power dissipation. As a worst-case example, compute the maximum T using a VCA820ID (SO-14 package) in the circuit of Figure 76 J operating at maximum gain and at the maximum specified ambient temperature of +85°C with a DC output voltageathalfthesupplyintoa100-ohmload. P = 10V(38mA) + 52/(4´100W) = 442.5mW D (7) Maximum T = +85°C + (0.449W´80°C/W) = 120.5°C J (8) This maximum operating junction temperature is well below most system level targets. Most applications should be lower because an absolute worst-case output stage power was assumed in this calculation of V /2, which is CC beyondtheoutputvoltagerangefortheVCA820. 38 SubmitDocumentationFeedback Copyright©2007–2015,TexasInstrumentsIncorporated ProductFolderLinks:VCA820

VCA820 www.ti.com SBOS395D–OCTOBER2007–REVISEDSEPTEMBER2015 12 Device and Documentation Support 12.1 Device Support 12.1.1 Third-PartyProductsDisclaimer TI'S PUBLICATION OF INFORMATION REGARDING THIRD-PARTY PRODUCTS OR SERVICES DOES NOT CONSTITUTE AN ENDORSEMENT REGARDING THE SUITABILITY OF SUCH PRODUCTS OR SERVICES OR A WARRANTY, REPRESENTATION OR ENDORSEMENT OF SUCH PRODUCTS OR SERVICES, EITHER ALONEORINCOMBINATIONWITHANYTIPRODUCTORSERVICE. 12.2 Community Resources The following links connect to TI community resources. Linked contents are provided "AS IS" by the respective contributors. They do not constitute TI specifications and do not necessarily reflect TI's views; see TI's Terms of Use. TIE2E™OnlineCommunity TI'sEngineer-to-Engineer(E2E)Community.Createdtofostercollaboration amongengineers.Ate2e.ti.com,youcanaskquestions,shareknowledge,exploreideasandhelp solveproblemswithfellowengineers. DesignSupport TI'sDesignSupport QuicklyfindhelpfulE2Eforumsalongwithdesignsupporttoolsand contactinformationfortechnicalsupport. 12.3 Trademarks E2EisatrademarkofTexasInstruments. X2YisaregisteredtrademarkofX2YAttenuatorsLLC. Allothertrademarksarethepropertyoftheirrespectiveowners. 12.4 Electrostatic Discharge Caution Thesedeviceshavelimitedbuilt-inESDprotection.Theleadsshouldbeshortedtogetherorthedeviceplacedinconductivefoam duringstorageorhandlingtopreventelectrostaticdamagetotheMOSgates. 12.5 Glossary SLYZ022—TIGlossary. Thisglossarylistsandexplainsterms,acronyms,anddefinitions. 13 Mechanical, Packaging, and Orderable Information The following pages include mechanical, packaging, and orderable information. This information is the most current data available for the designated devices. This data is subject to change without notice and revision of thisdocument.Forbrowser-basedversionsofthisdatasheet,refertotheleft-handnavigation. Copyright©2007–2015,TexasInstrumentsIncorporated SubmitDocumentationFeedback 39 ProductFolderLinks:VCA820

PACKAGE OPTION ADDENDUM www.ti.com 6-Feb-2020 PACKAGING INFORMATION Orderable Device Status Package Type Package Pins Package Eco Plan Lead/Ball Finish MSL Peak Temp Op Temp (°C) Device Marking Samples (1) Drawing Qty (2) (6) (3) (4/5) VCA820ID ACTIVE SOIC D 14 50 Green (RoHS NIPDAU Level-2-260C-1 YEAR -40 to 85 VCA820ID & no Sb/Br) VCA820IDGSR ACTIVE VSSOP DGS 10 2500 Green (RoHS NIPDAUAG Level-2-260C-1 YEAR -40 to 85 BOQ & no Sb/Br) VCA820IDGST ACTIVE VSSOP DGS 10 250 Green (RoHS NIPDAUAG Level-2-260C-1 YEAR -40 to 85 BOQ & no Sb/Br) VCA820IDR ACTIVE SOIC D 14 2500 Green (RoHS NIPDAU Level-2-260C-1 YEAR -40 to 85 VCA820ID & no Sb/Br) (1) The marketing status values are defined as follows: ACTIVE: Product device recommended for new designs. LIFEBUY: TI has announced that the device will be discontinued, and a lifetime-buy period is in effect. NRND: Not recommended for new designs. Device is in production to support existing customers, but TI does not recommend using this part in a new design. PREVIEW: Device has been announced but is not in production. Samples may or may not be available. OBSOLETE: TI has discontinued the production of the device. (2) RoHS: TI defines "RoHS" to mean semiconductor products that are compliant with the current EU RoHS requirements for all 10 RoHS substances, including the requirement that RoHS substance do not exceed 0.1% by weight in homogeneous materials. Where designed to be soldered at high temperatures, "RoHS" products are suitable for use in specified lead-free processes. TI may reference these types of products as "Pb-Free". RoHS Exempt: TI defines "RoHS Exempt" to mean products that contain lead but are compliant with EU RoHS pursuant to a specific EU RoHS exemption. Green: TI defines "Green" to mean the content of Chlorine (Cl) and Bromine (Br) based flame retardants meet JS709B low halogen requirements of <=1000ppm threshold. Antimony trioxide based flame retardants must also meet the <=1000ppm threshold requirement. (3) MSL, Peak Temp. - The Moisture Sensitivity Level rating according to the JEDEC industry standard classifications, and peak solder temperature. (4) There may be additional marking, which relates to the logo, the lot trace code information, or the environmental category on the device. (5) Multiple Device Markings will be inside parentheses. Only one Device Marking contained in parentheses and separated by a "~" will appear on a device. If a line is indented then it is a continuation of the previous line and the two combined represent the entire Device Marking for that device. (6) Lead/Ball Finish - Orderable Devices may have multiple material finish options. Finish options are separated by a vertical ruled line. Lead/Ball Finish values may wrap to two lines if the finish value exceeds the maximum column width. Important Information and Disclaimer:The information provided on this page represents TI's knowledge and belief as of the date that it is provided. TI bases its knowledge and belief on information provided by third parties, and makes no representation or warranty as to the accuracy of such information. Efforts are underway to better integrate information from third parties. TI has taken and Addendum-Page 1

PACKAGE OPTION ADDENDUM www.ti.com 6-Feb-2020 continues to take reasonable steps to provide representative and accurate information but may not have conducted destructive testing or chemical analysis on incoming materials and chemicals. TI and TI suppliers consider certain information to be proprietary, and thus CAS numbers and other limited information may not be available for release. In no event shall TI's liability arising out of such information exceed the total purchase price of the TI part(s) at issue in this document sold by TI to Customer on an annual basis. Addendum-Page 2

PACKAGE MATERIALS INFORMATION www.ti.com 6-May-2015 TAPE AND REEL INFORMATION *Alldimensionsarenominal Device Package Package Pins SPQ Reel Reel A0 B0 K0 P1 W Pin1 Type Drawing Diameter Width (mm) (mm) (mm) (mm) (mm) Quadrant (mm) W1(mm) VCA820IDGSR VSSOP DGS 10 2500 330.0 12.4 5.3 3.4 1.4 8.0 12.0 Q1 VCA820IDGST VSSOP DGS 10 250 180.0 12.4 5.3 3.4 1.4 8.0 12.0 Q1 VCA820IDR SOIC D 14 2500 330.0 16.4 6.5 9.0 2.1 8.0 16.0 Q1 PackMaterials-Page1

PACKAGE MATERIALS INFORMATION www.ti.com 6-May-2015 *Alldimensionsarenominal Device PackageType PackageDrawing Pins SPQ Length(mm) Width(mm) Height(mm) VCA820IDGSR VSSOP DGS 10 2500 367.0 367.0 35.0 VCA820IDGST VSSOP DGS 10 250 210.0 185.0 35.0 VCA820IDR SOIC D 14 2500 367.0 367.0 38.0 PackMaterials-Page2

PACKAGE OUTLINE DGS0010A VSSOP - 1.1 mm max height SCALE 3.200 SMALL OUTLINE PACKAGE C 5.05 4.75 TYP SEATING PLANE A PIN 1 ID 0.1 C AREA 8X 0.5 10 1 3.1 2X 2.9 NOTE 3 2 5 6 0.27 10X 0.17 B 3.1 0.1 C A B 1.1 MAX 2.9 NOTE 4 0.23 TYP SEE DETAIL A 0.13 0.25 GAGE PLANE 0.15 0.7 0 - 8 0.05 0.4 DETAIL A TYPICAL 4221984/A 05/2015 NOTES: 1. All linear dimensions are in millimeters. Any dimensions in parenthesis are for reference only. Dimensioning and tolerancing per ASME Y14.5M. 2. This drawing is subject to change without notice. 3. This dimension does not include mold flash, protrusions, or gate burrs. Mold flash, protrusions, or gate burrs shall not exceed 0.15 mm per side. 4. This dimension does not include interlead flash. Interlead flash shall not exceed 0.25 mm per side. 5. Reference JEDEC registration MO-187, variation BA. www.ti.com

EXAMPLE BOARD LAYOUT DGS0010A VSSOP - 1.1 mm max height SMALL OUTLINE PACKAGE 10X (1.45) 10X (0.3) SYMM (R0.05) TYP 1 10 SYMM 8X (0.5) 5 6 (4.4) LAND PATTERN EXAMPLE SCALE:10X SOOPLEDNEINRG MASK METAL MSOELTDAEL RU NMDAESRK SOOPLEDNEINRG MASK 0.05 MAX 0.05 MIN ALL AROUND ALL AROUND NON SOLDER MASK SOLDER MASK DEFINED DEFINED SOLDER MASK DETAILS NOT TO SCALE 4221984/A 05/2015 NOTES: (continued) 6. Publication IPC-7351 may have alternate designs. 7. Solder mask tolerances between and around signal pads can vary based on board fabrication site. www.ti.com

EXAMPLE STENCIL DESIGN DGS0010A VSSOP - 1.1 mm max height SMALL OUTLINE PACKAGE 10X (1.45) SYMM (R0.05) TYP 10X (0.3) 1 10 SYMM 8X (0.5) 5 6 (4.4) SOLDER PASTE EXAMPLE BASED ON 0.125 mm THICK STENCIL SCALE:10X 4221984/A 05/2015 NOTES: (continued) 8. Laser cutting apertures with trapezoidal walls and rounded corners may offer better paste release. IPC-7525 may have alternate design recommendations. 9. Board assembly site may have different recommendations for stencil design. www.ti.com

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