Amplifier and Data Converter Selection Guide (Rev. B

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6 Amplifiers➔Texas Instruments (TI) offers a wide range ofop amp types including high precision,microPower, low voltage, high voltage, highspeed and rail-to-rail in several differentprocess technologies. TI has developed theindustry's largest selection of low-power andlow-voltage op amps with features designedto satisfy a very wide range of applications.To help facilitate the selection process, aninteractive online op amp parametric searchengine is available at amplifier.ti.com/searchwith links to all op amp specifications.Design ConsiderationsChoosing the best op amp for an applicationinvolves consideration of a variety of interrelatedrequirements. In doing so, designersmust often consider conflicting size, cost andperformance objectives. Even experiencedengineers can find the task daunting, but itneed not be so. Keeping in mind the followingissues, the choices can quickly be narrowedto a manageable few.Supply voltage (V S )—tables include lowvoltage (< 2.7V min) and wide voltage range(> 5V min) sections. Other op amp selectioncriteria (e.g., precision) can be quickly examinedin the supply range column for anappropriate choice. Applications operatingfrom a single power supply may requirerail-to-rail performance and considerationof precision-related parameters.Precision—primarily associated with inputoffset voltage (V OS ) and its change withrespect to temperature drift, PSRR andCMRR. It is generally used to describe opamps with low input offset voltage and lowinput offset voltage temperature drift.Precision op amps are required whenamplifying tiny signals from thermocouplesand other low-level sensors. High-gain ormulti-stage circuits may require lowoffset voltage.Gain bandwidth product (GBW)—the gainbandwidth of a voltage-feedback op ampdetermines its useful bandwidth in anapplication. The maximum available bandwidthis approximately equal to the gain bandwidthdivided by the closed-loop gain of the application.For voltage feedback amplifiers, GBW isa constant. Many applications benefit fromchoosing a much wider bandwidth/slew rateop amp to achieve low distortion, excellentlinearity, good gain accuracy, gain flatnessor other behavior that is influenced byfeedback factors.Power (I Q requirements)—a significant issuein many applications. Because op amps canhave a considerable impact on the overallsystem power budget, quiescent current,especially in battery-powered applications,is a key design consideration.Rail-to-rail performance—rail-to-railoutput provides maximum output voltageswing for widest dynamic range. This may beparticularly important with low operatingvoltage where signal swings are limited.Rail-to-rail input capability is often requiredto achieve maximum signal swing in buffer(G = 1) single-supply applications. It can beuseful in other applications, depending onamplifier gain and biasing considerations.Voltage noise (V N )—amplifier-generatednoise may limit the ultimate dynamic range,accuracy or resolution of a system. Lownoiseop amps can improve accuracy, even inslow DC measurements.Input bias current (I B )—can create offseterror by reacting with source or feedbackimpedance. Applications with high sourceimpedance or high impedance feedbackelements (such as transimpedance amplifiersor integrators) often require low input biasCommon Op Amp Design QuestionsWhat is the amplitude of theinput signal?To ensure signal errors are small relative tothe input signal, small input signals requirehigh precision (e.g., low offset voltage)amplifiers. Ensure that the amplified outputsignal stays within the amplifieroutput voltage.Will the ambient temperature vary?Op amps are sensitive to temperaturevariations, so it is important to consideroffset voltage drift over temperature.Does the common-mode voltage vary?Make sure the op amp is operatedwithin its common-mode range and has anadequate common-mode rejection ratiocurrent. FET-Input and CMOS op ampsgenerally provide very low input bias current.Slew rate—the maximum rate of change ofthe amplifier output. It is important whendriving large signals to high frequency. Theavailable large signal bandwidth of an opamp is determined by the slew rateSR/.707(2π)V P .Package size—TI offers a wide variety ofmicroPackages, including WCSP, SOT23,SC70 and small, high power-dissipatingPowerPAD packages to meet spacesensitiveand high-output drive requirements.Many TI single-channel op amps areavailable in SOT23, with some dualamplifiers in SOT23-8.Shutdown mode—an enable/disablefunction that places the amp in a highimpedance state, reducing quiescent currentin many cases to less than 1µA. Allowsdesigners to use wide bandwidth op amps inlower power applications, enabling themonly when they are needed.Decompensated amplifiers—forapplications with gain greater than unitygain (G > 1), decompensated ampsprovide significantly higher bandwidth,improved slew rate and lower distortion overtheir unity-gain stable counterparts on thesame quiescent current or noise.(CMRR). Common-mode voltage will induceadditional offset voltage.Does the power supply voltage vary?Power supply variations affect theoffset voltage. This may be especiallyimportant in battery-powered applications.Precision Application Examples• High gain circuits (G > 100)• Measuring small input signals(e.g., from a thermocouple)• Wide operating temperature rangecircuits (i.e., in automotive orindustrial applications)• Single-supply ≤ 5V data-acquisitionsystems where input voltage spanis limitedAmplifier and Data Converter Selection Guide Texas Instruments 3Q 2007
Amplifiers 7Technology PrimerUnderstanding the relative advantages ofbasic semiconductor technologies will help inselecting the proper device for a specificapplication.CMOS Amps—when low voltage and/or lowpower consumption, excellent speed/power ratio,rail-to-rail performance, low cost and smallpackaging are primary design considerations,choose microPackaged CMOS amps boastingthe highest precision in the industry.High-Speed Bipolar Amps—when the highestspeed at the lowest power is required, bipolartechnology delivers the best performance.Extremely good power gain gives very highoutput power and full power bandwidths onthe lowest quiescent power. Higher voltagerequirements are also only satisfied in bipolartechnologies.Precision Bipolar Amps—excel in limitingerrors relating to offset voltage. These ampsinclude low offset voltage and temperaturedrift, high open-loop gain and common-moderejection. Precision bipolar op amps are usedextensively in applications where the sourceOperational Amplifier Naming Conventionsimpedance is low, such as a thermocoupleamplifier, and where voltage errors, offsetvoltage and drift, are crucial to accuracy.Low I B FET Amps—when input impedance isvery high, FET-input amps provide better overallprecision than bipolar-input amps becauseof very low input bias current. Using a bipolaramp in applications with high source impedance(e.g., 500MΩ pH probe), the offset, driftand noise produced by bias currents flowingthrough the source would render the circuitvirtually useless. When low current errors arerequired, FET amps provide extremely lowinput bias current, low offset current andhigh input impedance.Dielectrically Isolated FET (Difet ) Amps—Difet processing enables the design ofextremely low input leakage amplifiers byeliminating the substrate junction diodepresent in junction isolated processes. Thistechnique yields very high-precision, lownoiseop amps. Difet processes also minimizeparasitic capacitance and output transistorsaturation effects, resulting in improvedbandwidth and wider output swing.Op Amp Rapid SelectorThe tables on the following pageshave been subdivided into severalcategories to help quickly narrow thealternatives.Precision Offset Voltage(V OS < 500µV) Pg. 8Low Power(I Q < 500µA) Pg. 9Low Noise(V N ≤ 10nV/ Hz Pg. 10Low Input Bias Current(I B ≤ 10pA) Pg. 11Wide Bandwidth, PrecisionGBW > 5MHz Pg. 12Wide Voltage Range(±5 ≤ V S ≤ ±20V) Pg. 13Single Supply(V S (min) ≤ 2.7V) Pg. 14High SpeedBW ≥ 50MHz Pg. 17➔ChannelsSingle = No CharacterDual = 2Triple = 3Quad = 4OPA y 3 63Base Model100 = FET200 = Bipolar300 = CMOS (≤5.5V)400 = High Voltage (>40V)500 = High Power (>200mA)600 = High-Speed (>50MHz)700 = CMOS (12V)800 = High-Speed (>50MHz)Amp ClassTLV = Low Supply VoltageTLC = 5V CMOSTLE = Wide Supply VoltageTLV 278 xChannels and Shutdowon Options0 = Single with Shutdown1 = Single2 = Dual3 = Dual with Shutdown4 = Quad5 = Quad with ShutdownAmp ClassTHS = High SpeedTHS x y 01Amplifier Type30 = Current Feedback31 = Current Feedback40 = Voltage Feedback41 = Fully Differential42 = Voltage Feedback43 = Fast Voltage Feedback45 = Fully Differential46 = Transimpedance60 = Line Receiver61 = Line Driver73 = Programmable FiltersRecommendedRecommendedSupply Voltage Design Requirements Typical Applications Process TI Amp FamilyV S ≤ 5V Rail-to-Rail, Low Power, Precision, Small Packages Battery Powered, Handheld CMOS OPA3xx, TLVxxxxV S ≤ 16V Rail-to-Rail, Low Noise, Low Voltage Offset, Precision, Small Packages Industrial, Automotive CMOS OPA3x, TLCxxxx, OPA7xxV S ≤ +3V Low Input Bias Current, Low Offset Current, Industrial, Test Equipment, Optical Networking FET, Difet OPA1xx, OPA627High Input Impedance(ONET), High-End AudioV S ≤ +44V Low Voltage Offset, Low Drift Industrial, Test Equipment, ONET, High-End Audio Bipolar OPA2xx, TLExxxx±5V to ±15V High Speed on Dual Supplies XDSL, Video, Professional Imaging, Difet, High-Speed OPA6xx*, OPA8xx*Dual Supply Data Converter Signal Conditioning Bipolar, BiCOM THSxxxx*2.7V ≤ V S ≤ 5V High Speed on Single Supply Consumer Imaging, Data Converter Signal High-Speed CMOS OPA35x, OPA6xx*,Single Supply Conditioning, Safety-Critical Automotive THSxxxx*, OPA8xx**See High-Speed section, Page 15-19Texas Instruments 3Q 2007Amplifier and Data Converter Selection Guide
Page 8 and 9: 8Amplifiers➔Precision Operational
Page 10 and 11: 10 Amplifiers➔Precision Operation
Page 12 and 13: 12➔AmplifiersPrecision Operationa
Page 14 and 15: 14AmplifiersPrecision Operational A
Page 16 and 17: 16Amplifiers➔High-Speed Amplifier
Page 18 and 19: 18➔AmplifiersHigh-Speed Amplifier
Page 20 and 21: 20 Amplifiers➔Video AmplifiersVid
Page 22 and 23: 22Amplifiers➔Video AmplifiersVide
Page 24 and 25: 24➔AmplifiersComparatorsLow-Power
Page 26 and 27: 26 Amplifiers➔Difference Amplifie
Page 28 and 29: 28 Amplifiers➔Analog Current Shun
Page 30 and 31: 30 Amplifiers➔Instrumentation Amp
Page 32 and 33: 32➔AmplifiersSingle-Supply Instru
Page 34 and 35: 34 Amplifiers➔Programmable Gain A
Page 36 and 37: 36➔AmplifiersVoltage-Controlled G
Page 38 and 39: 38➔AmplifiersAudio AmplifiersPure
Page 40 and 41: 40Amplifiers➔Audio Power Amplifie
Page 42 and 43: 42 Amplifiers➔Power Amplifiers an
Page 44 and 45: 44 Amplifiers➔Pulse Width Modulat
Page 46 and 47: 46➔AmplifiersSensor Conditioners
Page 48 and 49: 48 Amplifiers➔Integrating Amplifi
Page 50 and 51: 50 Amplifiers➔Amplifiers for Driv
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52 ADCs by Architecture➔Delta-Sig
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54➔ADCs by ArchitectureDelta-Sigm
Page 56 and 57:
56 ADCs by Architecture➔Wide Band
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58 ADCs by Architecture➔SAR ADCsS
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60ADCs by Architecture➔SAR ADCs18
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62➔ADCs by ArchitectureSuccessive
Page 64 and 65:
64 ADCs by Architecture➔Pipeline
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66➔ADCs by ArchitecturePipeline A
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68➔ADCs by ArchitecturePipeline A
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70➔DACs by ArchitectureHigh-Accur
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72DACs by Architecture➔High-Accur
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74DACs by Architecture➔High-Accur
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76DACs by Architecture➔Current St
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78➔Analog Monitoring and ControlA
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80 Analog Monitoring and Control➔
Page 82 and 83:
82Voltage References➔ Voltage Ref
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84➔Temperature SensorsTemperature
Page 86 and 87:
86Quick Reference Selection TableAD
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Page 94 and 95:
94Quick Reference Selection TableDA
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96Quick Reference Selection TableDA
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98Quick Reference Audio Selection T
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100Quick Reference Audio Selection
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102➔Design and Evaluation ToolsFi
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104➔Design and Evaluation ToolsSi
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106➔Design and Evaluation ToolsEv
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108➔Design and Evaluation ToolsDa
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110➔Design and Evaluation ToolsDa
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112➔Design and Evaluation ToolsAm
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114➔Design and Evaluation ToolsAp
Page 116 and 117:
116Device Index➔DevicePageDAC7643
Page 118 and 119:
118Device Index➔DevicePageTLV2544
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Texas Instruments Incorporated14950
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Amplifier and Data Converter Selection Guide (Rev. B

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