FET-Input, Low Distortion Operational Amplifier datasheet (Rev. A) · 2020. 12. 14. · low...

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FEATURES LOW DISTORTION: 0.0003% at 1kHz LOW NOISE: 10nV/Hz HIGH SLEW RATE: 25V/µs WIDE GAIN-BANDWIDTH: 20MHz UNITY-GAIN STABLE WIDE SUPPLY RANGE: V S = ± 4.5 to ±24V DRIVES 600LOAD DUAL VERSION AVAILABLE (OPA2604) FET-Input, Low Distortion OPERATIONAL AMPLIFIER APPLICATIONS PROFESSIONAL AUDIO EQUIPMENT PCM DAC I/V CONVERTERS SPECTRAL ANALYSIS EQUIPMENT ACTIVE FILTERS TRANSDUCER AMPLIFIERS DATA ACQUISITION OPA604 DESCRIPTION The OPA604 is a FET-input operational amplifier designed for enhanced AC performance. Very low distortion, low noise and wide bandwidth provide superior performance in high quality audio and other applications requiring excellent dy- namic performance. New circuit techniques and special laser trimming of dynamic circuit performance yield very low harmonic distortion. The result is an op amp with exceptional sound quality. The low- noise FET input of the OPA604 provides wide dynamic range, even with high source impedance. Offset voltage is laser-trimmed to minimize the need for interstage coupling capacitors. The OPA604 is available in 8-pin plastic mini-DIP and SO-8 surface-mount packages, specified for the –25°C to +85°C temperature range. Distortion Rejection Circuitry (1) (3) (+) (2) (–) (7) V+ (6) V O (4) V– Output Stage (1) NOTE: (1) Patents Granted: #5053718, 5019789 (5) (1) OPA604 OPA604 SBOS019A – JANUARY 1992 – SEPTEMBER 2003 www.ti.com PRODUCTION DATA information is current as of publication date. Products conform to specifications per the terms of Texas Instruments standard warranty. Production processing does not necessarily include testing of all parameters. Copyright © 1992-2003, Texas Instruments Incorporated Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet. All trademarks are the property of their respective owners.
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Transcript of FET-Input, Low Distortion Operational Amplifier datasheet (Rev. A) · 2020. 12. 14. · low...

  • FEATURES● LOW DISTORTION: 0.0003% at 1kHz

    ● LOW NOISE: 10nV/√Hz● HIGH SLEW RATE: 25V/µs● WIDE GAIN-BANDWIDTH: 20MHz

    ● UNITY-GAIN STABLE

    ● WIDE SUPPLY RANGE: VS = ±4.5 to ±24V● DRIVES 600Ω LOAD● DUAL VERSION AVAILABLE (OPA2604)

    FET-Input, Low DistortionOPERATIONAL AMPLIFIER

    APPLICATIONS● PROFESSIONAL AUDIO EQUIPMENT

    ● PCM DAC I/V CONVERTERS

    ● SPECTRAL ANALYSIS EQUIPMENT

    ● ACTIVE FILTERS

    ● TRANSDUCER AMPLIFIERS

    ● DATA ACQUISITION

    OPA604

    DESCRIPTIONThe OPA604 is a FET-input operational amplifier designedfor enhanced AC performance. Very low distortion, low noiseand wide bandwidth provide superior performance in highquality audio and other applications requiring excellent dy-namic performance.

    New circuit techniques and special laser trimming of dynamiccircuit performance yield very low harmonic distortion. Theresult is an op amp with exceptional sound quality. The low-noise FET input of the OPA604 provides wide dynamicrange, even with high source impedance. Offset voltage islaser-trimmed to minimize the need for interstage couplingcapacitors.

    The OPA604 is available in 8-pin plastic mini-DIP and SO-8surface-mount packages, specified for the –25°C to +85°Ctemperature range.

    DistortionRejectionCircuitry(1)

    (3)

    (+)

    (2)

    (–)

    (7)V+

    (6)VO

    (4)V–

    OutputStage(1)

    NOTE: (1) Patents Granted: #5053718, 5019789

    (5)

    (1)

    OPA604 OPA604

    SBOS019A – JANUARY 1992 – SEPTEMBER 2003

    www.ti.com

    PRODUCTION DATA information is current as of publication date.Products conform to specifications per the terms of Texas Instrumentsstandard warranty. Production processing does not necessarily includetesting of all parameters.

    Copyright © 1992-2003, Texas Instruments Incorporated

    Please be aware that an important notice concerning availability, standard warranty, and use in critical applications ofTexas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.

    All trademarks are the property of their respective owners.

  • OPA6042SBOS019Awww.ti.com

    ABSOLUTE MAXIMUM RATINGS

    Power Supply Voltage ....................................................................... ±25VInput Voltage ............................................................... (V–)–1V to (V+)+1VOutput Short Circuit to Ground ................................................ ContinuousOperating Temperature .................................................. –40°C to +100°CStorage Temperature ...................................................... –40°C to +125°CJunction Temperature .................................................................... +150°CLead Temperature (soldering, 10s) AP .......................................... +300°CLead Temperature (soldering, 3s) AU ............................................ +260°C

    PIN CONFIGURATION

    Top View DIP, SOIC

    1

    2

    3

    4

    Offset Trim

    –In

    +In

    –VS

    8

    7

    6

    5

    No Internal Connection

    +VS

    Output

    Offset Trim

    ELECTROSTATICDISCHARGE SENSITIVITY

    Any integrated circuit can be damaged by ESD. Texas Instru-ments recommends that all integrated circuits be handled withappropriate precautions. Failure to observe proper handlingand installation procedures can cause damage.

    ESD damage can range from subtle performance degradationto complete device failure. Precision integrated circuits may bemore susceptible to damage because very small parametricchanges could cause the device not to meet published speci-fications.

    PACKAGE/ORDERING INFORMATION

    For the most current package and ordering information, seeto the Package Option Addendum at the end of this datasheet.

  • OPA604 3SBOS019A www.ti.com

    ELECTRICAL CHARACTERISTICSTA = +25°C, VS = ±15V, unless otherwise noted.

    OPA604AP, AU

    PARAMETER CONDITION MIN TYP MAX UNITS

    OFFSET VOLTAGEInput Offset Voltage ±1 ±5 mVAverage Drift ±8 µV/°CPower Supply Rejection VS = ±5 to ±24V 80 100 dB

    INPUT BIAS CURRENT(1)

    Input Bias Current VCM = 0V 50 pAInput Offset Current VCM = 0V ±3 pA

    NOISEInput Voltage NoiseNoise Density: f = 10Hz 25 nV/√Hz

    f = 100Hz 15 nV/√Hzf = 1kHz 11 nV/√Hzf = 10kHz 10 nV/√Hz

    Voltage Noise, BW = 20Hz to 20kHz 1.5 µVPPInput Bias Current NoiseCurrent Noise Density, f = 0.1Hz to 20kHz 4 fA/√Hz

    INPUT VOLTAGE RANGECommon-Mode Input Range ±12 ±13 VCommon-Mode Rejection VCM = ±12V 80 100 dB

    INPUT IMPEDANCEDifferential 1012 || 8 Ω || pFCommon-Mode 1012 || 10 Ω || pF

    OPEN-LOOP GAINOpen-Loop Voltage Gain VO = ±10V, RL = 1kΩ 80 100 dB

    FREQUENCY RESPONSEGain-Bandwidth Product G = 100 20 MHzSlew Rate 20VPP, RL = 1kΩ 15 25 V/µsSettling Time: 0.01% G = –1, 10V Step 1.5 µs

    0.1% 1 µsTotal Harmonic Distortion + Noise (THD+N) G = 1, f = 1kHz 0.0003 %

    VO = 3.5Vrms, RL = 1kΩ

    OUTPUTVoltage Output RL = 600Ω ±11 ±12 VCurrent Output VO = ±12V ±35 mAShort Circuit Current ±40 mAOutput Resistance, Open-Loop 25 Ω

    POWER SUPPLYSpecified Operating Voltage ±15 VOperating Voltage Range ±4.5 ±24 VCurrent ±5.3 ±7 mA

    TEMPERATURE RANGESpecification –25 +85 °CStorage –40 +125 °CThermal Resistance(2), θJA 90 °C/W

    NOTES: (1) Typical performance, measured fully warmed-up. (2) Soldered to circuit board—see text.

  • OPA6044SBOS019Awww.ti.com

    TYPICAL CHARACTERISTICSTA = +25°C, VS = ±15V, unless otherwise noted.

    TOTAL HARMONIC DISTORTION + NOISEvs FREQUENCY

    Frequency (Hz)

    TH

    D +

    N (

    %)

    1

    0.1

    0.01

    0.001

    0.0001

    20 100 1k 10k 20k

    G = 100V/V

    G = 10V/V

    G = 1V/V

    Measurement BW = 80kHzSee “Distortion Measure-ments” for description oftest method.

    1kΩ

    V =3.5Vrms

    O

    TOTAL HARMONIC DISTORTION + NOISEvs OUTPUT VOLTAGE

    Output Voltage (VPP)

    TH

    D +

    N (

    %)

    0.1 1 10 100

    0.1

    0.01

    0.001

    0.0001

    1kΩ

    V O

    f = 1kHzMeasurement BW = 80kHz

    See “Distortion Measurements”for description of test method.

    OPEN-LOOP GAIN/PHASE vs FREQUENCY

    Frequency (Hz)

    Vol

    tage

    Gai

    n (d

    B)

    120

    100

    80

    60

    40

    20

    0

    –201 10 100 1k 10k 100k 1M 10M

    0

    –45

    –90

    –135

    –180

    Pha

    se S

    hift

    (Deg

    rees

    )

    G

    φ

    INPUT VOLTAGE AND CURRENT NOISESPECTRAL DENSITY vs FREQUENCY

    Frequency (Hz)

    Vol

    tage

    Noi

    se (

    nV/

    Hz)

    1

    1k

    100

    10

    110 100 1k 10k 100k 1M

    Cur

    rent

    Noi

    se (

    fA/

    Hz)

    1k

    100

    10

    1

    Voltage Noise

    Current Noise

    INPUT BIAS AND INPUT OFFSET CURRENT vs TEMPERATURE

    Ambient Temperature (°C)

    Inpu

    t Bia

    s C

    urre

    nt (

    pA)

    –75

    100nA

    10nA

    1nA

    100

    10

    1

    Inpu

    t Offs

    et C

    urre

    nt (

    pA)

    10nA

    1nA

    100

    10

    1

    0.1–50 –25 0 25 50 75 100 125

    InputOffset Current

    InputBias Current

    INPUT BIAS AND INPUT OFFSET CURRENT vs INPUT COMMON-MODE VOLTAGE

    Common-Mode Voltage (V)

    Inpu

    t Bia

    s C

    urre

    nt (

    pA)

    –15

    10nA

    1nA

    100

    10

    Inpu

    t Offs

    et C

    urre

    nt (

    pA)

    1nA

    100

    10

    1–10 –5 0 5 10 15

    InputOffset Current

    InputBias Current

  • OPA604 5SBOS019A www.ti.com

    TYPICAL CHARACTERISTICS (Cont.)TA = +25°C, VS = ±15V, unless otherwise noted.

    COMMON-MODE REJECTION vs COMMON-MODE VOLTAGE

    Common-Mode Voltage (V)

    Com

    mon

    -Mod

    e R

    ejec

    tion

    (dB

    )

    –15

    120

    110

    100

    90

    80–10 –5 0 5 10 15

    POWER SUPPLY AND COMMON-MODEREJECTION vs FREQUENCY

    Frequency (Hz)

    Pow

    er S

    uppl

    y R

    ejec

    tion

    (dB

    )

    10

    120

    100

    80

    60

    40

    20

    0100 1k 10k 100k 1M 10M

    Com

    mon

    -Mod

    e R

    ejec

    tion

    (dB

    )120

    100

    80

    60

    40

    20

    0

    +PSR

    –PSRCMR

    AOL, PSR, AND CMR vs SUPPLY VOLTAGE

    Supply Voltage (±VS)

    AO

    L, P

    SR

    , CM

    R (

    dB)

    5

    120

    110

    100

    90

    80

    7010 15 20 25

    CMR

    AOL

    PSR

    GAIN-BANDWIDTH AND SLEW RATEvs TEMPERATURE

    Temperature (°C)

    Gai

    n-B

    andw

    idth

    (M

    Hz)

    –75

    28

    24

    20

    16

    12–25 25 75 125

    Sle

    w R

    ate

    (V/µ

    s)

    30

    25

    20

    15

    10–50 0 50 100

    Slew Rate

    Gain-BandwidthG = +100

    INPUT BIAS CURRENT vs TIME FROM POWER TURN-ON

    Time After Power Turn-On (min)

    Inpu

    t Bia

    s C

    urre

    nt (

    pA)

    0

    1nA

    100

    10

    11 2 3 4 5

    VS = ±24V

    VS = ±15V

    VS = ±5V

    GAIN-BANDWIDTH AND SLEW RATEvs SUPPLY VOLTAGE

    Supply Voltage (±VS)

    Gai

    n-B

    andw

    idth

    (M

    Hz)

    5

    28

    24

    20

    16

    1210 15 20 25

    Slew RateGain-BandwidthG = +100

    Sle

    w R

    ate

    (V/µ

    s)

    33

    29

    25

    21

    17

  • OPA6046SBOS019Awww.ti.com

    TYPICAL CHARACTERISTICS (Cont.)T

    A = +25°C, V

    S = ±15V, unless otherwise noted.

    0

    SETTLING TIME vs CLOSED-LOOP GAIN

    Closed-Loop Gain (V/V)

    Set

    tling

    Tim

    e (µ

    s)

    –1

    5

    4

    3

    2

    1

    0–10 –100 –1000

    0.01%

    0.1%

    VO = 10V StepRL = 1kΩCL = 50pF

    MAXIMUM OUTPUT VOLTAGE SWING vs FREQUENCY

    Frequency (Hz)

    Out

    put V

    olta

    ge (

    Vp-

    p)

    10k

    30

    20

    10

    0100k 1M 10M

    V = ±15VS

    SUPPLY CURRENT vs TEMPERATURE

    Ambient Temperature (°C)

    Sup

    ply

    Cur

    rent

    (m

    A)

    −75

    7

    6

    5

    4

    3−50 −25 0 25 50 75 100 125

    VS = ±24V

    VS = ±15V

    VS = ±5V

    SHORT-CIRCUIT CURRENT vs TEMPERATURE

    Ambient Temperature (°C)

    Sho

    rt-C

    ircui

    t Cur

    rent

    (m

    A)

    –75

    60

    50

    40

    30

    20–50 –25 0 25 50 75 100 125

    ISC+ and ISC–

    –100

    +100

    21

    Out

    put

    Vol

    tage

    (V

    )

    SMALL-SIGNAL TRANSIENT RESPONSE

    0

    –10

    +10

    105

    Out

    put

    Vol

    tage

    (V

    )LARGE-SIGNAL TRANSIENT RESPONSE

  • OPA604 7SBOS019A www.ti.com

    TYPICAL CHARACTERISTICS (Cont.)T

    A = +25°C, V

    S = ±15V, unless otherwise noted.

    APPLICATIONS INFORMATIONOFFSET VOLTAGE ADJUSTMENT

    The OPA604 offset voltage is laser-trimmed and will requireno further trim for most applications. As with most amplifiers,externally trimming the remaining offset can change driftperformance by about 0.3µV/°C for each 100µV of adjustedoffset. The OPA604 can replace many other amplifiers byleaving the external null circuit unconnected.

    The OPA604 is unity-gain stable, making it easy to use in awide range of circuitry. Applications with noisy or high imped-ance power supply lines may require decoupling capacitorsclose to the device pins. In most cases, a 1µF tantalumcapacitor at each power supply pin is adequate.

    DISTORTION MEASUREMENTS

    The distortion produced by the OPA604 is below the mea-surement limit of virtually all commercially available equip-ment. A special test circuit, however, can be used to extendthe measurement capabilities.

    Op amp distortion can be considered an internal error sourcewhich can be referred to the input. Figure 2 shows a circuitwhich causes the op amp distortion to be 101 times greaterthan normally produced by the op amp. The addition of R3 tothe otherwise standard noninverting amplifier configurationalters the feedback factor or noise gain of the circuit. Theclosed-loop gain is unchanged, but the feedback availablefor error correction is reduced by a factor of 101. Thisextends the measurement limit, including the effects of thesignal-source purity, by a factor of 101. Note that the inputsignal and load applied to the op amp are the same as withconventional feedback without R3.

    Validity of this technique can be verified by duplicatingmeasurements at high gain and/or high frequency where thedistortion is within the measurement capability of the testequipment. Measurements for this data sheet were madewith the Audio Precision System One, which greatly simpli-fies such repetitive measurements. The measurement tech-nique can, however, be performed with manual distortionmeasurement instruments.

    CAPACITIVE LOADS

    The dynamic characteristics of the OPA604 have beenoptimized for commonly encountered gains, loads and oper-ating conditions. The combination of low closed-loop gainand capacitive load will decrease the phase margin and maylead to gain peaking or oscillations. Load capacitance reactswith the op amp’s open-loop output resistance to form anadditional pole in the feedback loop. Figure 3 shows variouscircuits which preserve phase margin with capacitive load.For details of analysis techniques and applications circuits,refer to application bulletin AB-028 (SBOA015) located atwww.ti.com.

    FIGURE 1. Offset Voltage Trim.

    Supply Voltage, ±VS (V)

    6 8 10 12 14 16 18 20 22 24

    0.5

    0.45

    0.40

    0.35

    0.30

    0.25

    0.20

    0.15

    0.10

    0.05

    Pow

    er D

    issi

    patio

    n (W

    )POWER DISSIPATION vs SUPPLY VOLTAGE

    No signalor no load

    Typical high-levelmusic RL = 600Ω

    Worst case sinewave RL = 600Ω

    Ambient Temperature (°C)

    0

    1.4

    1.2

    1.0

    0.8

    0.6

    0.4

    0.2

    0

    Tot

    al P

    ower

    Dis

    sipa

    tion

    (W)

    MAXIMUM POWER DISSIPATION vs TEMPERATURE

    25 50 75 100 125 150

    J-A = 90°C/WSoldered to

    Circuit Board(see text)

    θ

    MaximumSpecified Operating

    Temperature85°C

    OPA604

    ±50mV TypicalTrim Range

    NOTE: (1) 50kΩ to 1MΩTrim Potentiometer(100kΩ Recommended)

    +VCC

    –VCC

    7

    6

    5

    1

    (1)

    4

    3

    2

  • OPA6048SBOS019Awww.ti.com

    For the unity-gain buffer, Figure 3a, stability is preserved byadding a phase-lead network, RC and CC. Voltage dropacross RC will reduce output voltage swing with heavy loads.An alternate circuit, Figure 3b, does not limit the output withlow load impedance. It provides a small amount of positivefeedback to reduce the net feedback factor. Input impedanceof this circuit falls at high frequency as op amp gain rolloffreduces the bootstrap action on the compensation network.

    Figures 3c and 3d show compensation techniques fornoninverting amplifiers. Like the follower circuits, the circuit inFigure 3d eliminates voltage drop due to load current, but atthe penalty of somewhat reduced input impedance at highfrequency.

    Figures 3e and 3f show input lead compensation networksfor inverting and difference amplifier configurations.

    NOISE PERFORMANCE

    Op amp noise is described by two parameters—noise volt-age and noise current. The voltage noise determines thenoise performance with low source impedance. Low noisebipolar-input op amps such as the OPA27 and OPA37provide very low voltage noise. But if source impedance isgreater than a few thousand ohms, the current noise of

    bipolar-input op amps react with the source impedance andwill dominate. At a few thousand ohms source impedanceand above, the OPA604 will generally provide lower noise.

    POWER DISSIPATION

    The OPA604 is capable of driving a 600Ω load with power-supply voltages up to ±24V. Internal power dissipation isincreased when operating at high power supply voltage. Thetypical characteristic curve, Power Dissipation vs PowerSupply Voltage, shows quiescent dissipation (no signal or noload) as well as dissipation with a worst case continuous sinewave. Continuous high-level music signals typically producedissipation significantly less than worst-case sine waves.

    Copper leadframe construction used in the OPA604 im-proves heat dissipation compared to conventional plasticpackages. To achieve best heat dissipation, solder the de-vice directly to the circuit board and use wide circuit boardtraces.

    OUTPUT CURRENT LIMIT

    Output current is limited by internal circuitry to approximately±40mA at 25°C. The limit current decreases with increasingtemperature as shown in the typical curves.

    FIGURE 2. Distortion Test Circuit.

    R2

    OPA604

    R1

    R3 VO = 10Vp-p (3.5Vrms)

    GeneratorOutput

    AnalyzerInput

    Audio PrecisionSystem OneAnalyzer(1)

    RL1kΩ

    IBM PCor

    Compatible

    SIG.GAIN

    DIST.GAIN R1 R2 R3

    500Ω

    50Ω

    5kΩ

    5kΩ

    5kΩ

    50Ω

    500Ω

    1

    10

    100

    101

    101

    101

    NOTE: (1) Measurement BW = 80kHz

  • OPA604 9SBOS019A www.ti.com

    FIGURE 3. Driving Large Capacitive Loads.

    NOTE: Design equations and component values are approximate. User adjustment is required for optimum performance.

    CC

    820pF

    RC

    750Ω

    CL5000pF

    ei

    CC = 120 X 10–12 CL

    (a)

    eo

    CL5000pF

    ei

    RC =

    (b)

    RC

    10Ω

    CC0.47µF

    R2

    2kΩ

    R24CL X 1010 – 1

    CC =CL X 103

    RC

    eo

    CL5000pF

    R2

    10kΩ

    R1

    10kΩ

    CC =50R2

    CL

    ei

    RC

    25Ω

    CC

    24pF

    (c)

    eo

    CL5000pF

    R2

    2kΩ

    R1

    2kΩ

    ei

    RC20Ω

    CC0.22µF

    (d)

    RC =R2

    2CL X 1010 – (1 + R2/R1)

    eo

    CL5000pF

    R2

    2kΩ

    R1

    2kΩei

    RC20Ω

    CC0.22µF

    (e)

    RC =R2

    2CL X 1010 – (1 + R2/R1)

    eo

    CL5000pF

    R2

    2kΩ

    R1

    2kΩe1

    RC20Ω

    CC0.22µF

    (f)

    RC =R2

    2CL X 1010 – (1 + R2/R1)

    R3

    2kΩe2

    R4

    2kΩ

    eo

    OPA604

    CC =CL X 103

    RC

    CC =CL X 103

    RC

    CC =CL X 103

    RC

    OPA604

    OPA604

    OPA604

    OPA604

    OPA604

  • OPA60410SBOS019Awww.ti.com

    FIGURE 5. Three-Pole Generalized Immittance Converter (GIC) Low-Pass Filter.

    FIGURE 4. Three-Pole Low-Pass Filter.

    R5

    2kΩ

    VO

    C31000pF

    Low-pass3-pole Butterworthf–3dB = 40kHz

    R1

    6.04kΩVIN

    R24.02kΩ

    R24.02kΩ

    C21000pF

    C11000pF

    R45.36kΩ

    See Application Bulletin AB-026for information on GIC filters.

    1 2

    OPA2604

    1 2

    OPA2604

    OPA604

    FIGURE 6. Differential Amplifier with Low-Pass Filter.

    R4

    22kΩ

    R3

    10kΩ VOC22000pF

    R2

    22kΩ

    C13000pF

    R1

    2.7kΩVIN

    fp = 20kHz

    C3

    100pF

    OPA604

    VOG = 1

    100pF

    VIN

    +

    7.87kΩ

    7.87kΩ

    10kΩ 10kΩ

    10kΩ 10kΩ100kHz Input Filter

    OPA604

    1 2

    OPA2604

    1 2

    OPA2604

  • OPA604 11SBOS019A www.ti.com

    FIGURE 8. Digital Audio DAC I-V Amplifier.FIGURE 7. High Impedance Amplifier.

    FIGURE 9. Using Two OPA604 Op Amps to Double the Output Current to a Load.

    OPA604OPA604

    A1

    A2

    VIN

    R1

    R2I1

    R451Ω

    I2

    OPA604

    R351Ω

    IL = I1 + I2

    Load

    VOUT = VIN (1+R2/R1)

    VOUT

    OPA604

    G = 101 (40dB)

    100Ω 10kΩ

    PiezoelectricTransducer

    1MΩ(1)

    NOTE: (1) Provides inputbias current return path.

    OPA604

    VO = ±3Vp

    RF = Internal feedback resistance = 1.5kΩfC = Crossover frequency = 8MHz

    C1(1)

    NOTE: (1) C1 ≈COUT

    2π Rf fc

    To low-passfilter.

    OPA604

    5

    6

    9

    PCM6320-bitD/A

    Converter

    10

  • OPA60412SBOS019Awww.ti.com

    1

    00 1

    IC(mA)

    0 5

    log(VO)

    1 2 3 4

    fO 2fO 3fO 4fO 5fO

    VBE = 1kHz + DC Bias

    VBE (V)0.65

    FFT

    Frequency (kHz)

    1

    01 0

    –ID(mA)

    0 5

    log(VO)

    1 2 3 4

    fO 2fO 3fO 4fO 5fO

    VGS = 1kHz + DC Bias

    VGS (V)

    FFT

    Frequency (kHz)

    VO

    ID

    VGS

    VO

    IC

    VBE

    FIGURE 10. I-V and Spectral Response of NPN andJFET.

    THE OPA604 DESIGN

    The OPA604 uses FETs throughout the signal path,including the input stage, input-stage load, and theimportant phase-splitting section of the output stage.Bipolar transistors are used where their attributes,such as current capability are important, and wheretheir transfer characteristics have minimal impact.

    The topology consists of a single folded-cascode gainstage followed by a unity-gain output stage. Differen-tial input transistors J1 and J2 are special large-geom-etry, P-channel JFETs. Input stage current is a rela-tively high 800µA, providing high transconductanceand reducing voltage noise. Laser trimming of stagecurrents and careful attention to symmetry yields anearly symmetrical slew rate of ±25V/µs.

    The JFET input stage holds input bias current toapproximately 50pA or roughly 3000 times lower thancommon bipolar-input audio op amps. This dramati-cally reduces noise with high-impedance circuitry.

    The drains of J1 and J2 are cascoded by Q1 and Q2,driving the input stage loads, FETs J3 and J4. Distor-tion reduction circuitry (patented) linearizes the open-loop response and increases voltage gain. The 20MHzbandwidth of the OPA604 further reduces distortionthrough the user-connected feedback loop.

    The output stage consists of a JFET phase-splitterloaded into high speed all-NPN output drivers. Outputtransistors are biased by a special circuit to preventcutoff, even with full output swing into 600Ω loads.

    The following discussion is provided, recognizing thatnot all measured performance behavior explains orcorrelates with listening tests by audio experts. Thedesign of the OPA604 included consideration of bothobjective performance measurements, as well as anawareness of widely held theory on the success andfailure of previous op amp designs.

    SOUND QUALITY

    The sound quality of an op amp is often the crucialselection criteria—even when a data sheet claimsexceptional distortion performance. By its nature, soundquality is subjective. Furthermore, results of listeningtests can vary depending on application and circuitconfiguration. Even experienced listeners in controlledtests often reach different conclusions.

    Many audio experts believe that the sound quality of ahigh performance FET op amp is superior to that ofbipolar op amps. A possible reason for this is thatbipolar designs generate greater odd-order harmonicsthan FETs. To the human ear, odd-order harmonicshave long been identified as sounding more unpleas-ant than even-order harmonics. FETs, like vacuumtubes, have a square-law I-V transfer function which ismore linear than the exponential transfer function of abipolar transistor. As a direct result of this square-lawcharacteristic, FETs produce predominantly even-or-der harmonics. Figure 10 shows the transfer function ofa bipolar transistor and FET. Fourier transformation ofboth transfer functions reveals the lower odd-orderharmonics of the FET amplifier stage.

    SOUND QUALITY

    DistortionRejectionCircuitry

    (+)

    (–)OutputStage

    R31kΩ

    R41kΩ

    R83kΩ

    R93kΩ

    R175Ω

    R275Ω

    R5500Ω

    R74kΩ

    R6500Ω

    I1800µA

    J1 J2 J3 J4

    Q4

    Q2Q3Q1

    J5

    I2

    200µA

    R1010kΩ

    R1110kΩ

  • PACKAGE OPTION ADDENDUM

    www.ti.com 13-Aug-2021

    Addendum-Page 1

    PACKAGING INFORMATION

    Orderable Device Status(1)

    Package Type PackageDrawing

    Pins PackageQty

    Eco Plan(2)

    Lead finish/Ball material

    (6)

    MSL Peak Temp(3)

    Op Temp (°C) Device Marking(4/5)

    Samples

    OPA604AP ACTIVE PDIP P 8 50 RoHS & Green NIPDAU N / A for Pkg Type -40 to 85 OPA604AP

    OPA604APG4 ACTIVE PDIP P 8 50 RoHS & Green NIPDAU N / A for Pkg Type -40 to 85 OPA604AP

    OPA604AU ACTIVE SOIC D 8 75 RoHS & Green NIPDAU Level-3-260C-168 HR -40 to 85 OPA604AU

    OPA604AU/2K5 ACTIVE SOIC D 8 2500 RoHS & Green NIPDAU Level-3-260C-168 HR -40 to 85 OPA604AU

    OPA604AU/2K5G4 ACTIVE SOIC D 8 2500 RoHS & Green NIPDAU Level-3-260C-168 HR -40 to 85 OPA604AU

    OPA604AUE4 ACTIVE SOIC D 8 75 RoHS & Green NIPDAU Level-3-260C-168 HR -40 to 85 OPA604AU

    (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 substancedo 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 mayreference 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

  • PACKAGE OPTION ADDENDUM

    www.ti.com 13-Aug-2021

    Addendum-Page 2

    (6) Lead finish/Ball material - Orderable Devices may have multiple material finish options. Finish options are separated by a vertical ruled line. Lead finish/Ball material values may wrap to twolines 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 informationprovided 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 andcontinues 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.

  • TAPE AND REEL INFORMATION

    *All dimensions are nominal

    Device PackageType

    PackageDrawing

    Pins SPQ ReelDiameter

    (mm)

    ReelWidth

    W1 (mm)

    A0(mm)

    B0(mm)

    K0(mm)

    P1(mm)

    W(mm)

    Pin1Quadrant

    OPA604AU/2K5 SOIC D 8 2500 330.0 12.4 6.4 5.2 2.1 8.0 12.0 Q1

    PACKAGE MATERIALS INFORMATION

    www.ti.com 1-Nov-2020

    Pack Materials-Page 1

  • *All dimensions are nominal

    Device Package Type Package Drawing Pins SPQ Length (mm) Width (mm) Height (mm)

    OPA604AU/2K5 SOIC D 8 2500 853.0 449.0 35.0

    PACKAGE MATERIALS INFORMATION

    www.ti.com 1-Nov-2020

    Pack Materials-Page 2

  • www.ti.com

    PACKAGE OUTLINE

    C

    .228-.244 TYP[5.80-6.19]

    .069 MAX[1.75]

    6X .050[1.27]

    8X .012-.020 [0.31-0.51]

    2X.150[3.81]

    .005-.010 TYP[0.13-0.25]

    0 - 8 .004-.010[0.11-0.25]

    .010[0.25]

    .016-.050[0.41-1.27]

    4X (0 -15 )

    A

    .189-.197[4.81-5.00]

    NOTE 3

    B .150-.157[3.81-3.98]

    NOTE 4

    4X (0 -15 )

    (.041)[1.04]

    SOIC - 1.75 mm max heightD0008ASMALL OUTLINE INTEGRATED CIRCUIT

    4214825/C 02/2019

    NOTES: 1. Linear dimensions are in inches [millimeters]. Dimensions in parenthesis are for reference only. Controlling dimensions are in inches. 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 .006 [0.15] per side. 4. This dimension does not include interlead flash.5. Reference JEDEC registration MS-012, variation AA.

    18

    .010 [0.25] C A B

    54

    PIN 1 ID AREA

    SEATING PLANE

    .004 [0.1] C

    SEE DETAIL A

    DETAIL ATYPICAL

    SCALE 2.800

  • www.ti.com

    EXAMPLE BOARD LAYOUT

    .0028 MAX[0.07]ALL AROUND

    .0028 MIN[0.07]ALL AROUND

    (.213)[5.4]

    6X (.050 )[1.27]

    8X (.061 )[1.55]

    8X (.024)[0.6]

    (R.002 ) TYP[0.05]

    SOIC - 1.75 mm max heightD0008ASMALL OUTLINE INTEGRATED CIRCUIT

    4214825/C 02/2019

    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.

    METALSOLDER MASKOPENING

    NON SOLDER MASKDEFINED

    SOLDER MASK DETAILS

    EXPOSEDMETAL

    OPENINGSOLDER MASK METAL UNDER

    SOLDER MASK

    SOLDER MASKDEFINED

    EXPOSEDMETAL

    LAND PATTERN EXAMPLEEXPOSED METAL SHOWN

    SCALE:8X

    SYMM

    1

    45

    8

    SEEDETAILS

    SYMM

  • www.ti.com

    EXAMPLE STENCIL DESIGN

    8X (.061 )[1.55]

    8X (.024)[0.6]

    6X (.050 )[1.27]

    (.213)[5.4]

    (R.002 ) TYP[0.05]

    SOIC - 1.75 mm max heightD0008ASMALL OUTLINE INTEGRATED CIRCUIT

    4214825/C 02/2019

    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.

    SOLDER PASTE EXAMPLEBASED ON .005 INCH [0.125 MM] THICK STENCIL

    SCALE:8X

    SYMM

    SYMM

    1

    45

    8

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    Mailing Address: Texas Instruments, Post Office Box 655303, Dallas, Texas 75265Copyright © 2021, Texas Instruments Incorporated

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