This document is posted to help you gain knowledge. Please leave a comment to let me know what you think about it! Share it to your friends and learn new things together.
Transcript
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.
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
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.
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
R3
1kΩR4
1kΩR8
3kΩR9
3kΩ
R1
75ΩR2
75ΩR5
500ΩR7
4kΩ
R6
500Ω
I1800µA
J1 J2 J3 J4
Q4
Q2Q3Q1
J5
I2
200µA
R1010kΩ
R1110kΩ
PACKAGE OPTION ADDENDUM
www.ti.com 6-Sep-2016
Addendum-Page 1
PACKAGING INFORMATION
Orderable Device Status(1)
Package Type PackageDrawing
Pins PackageQty
Eco Plan(2)
Lead/Ball Finish(6)
MSL Peak Temp(3)
Op Temp (°C) Device Marking(4/5)
Samples
OPA604AP ACTIVE PDIP P 8 50 Green (RoHS& no Sb/Br)
CU NIPDAU N / A for Pkg Type -40 to 85 OPA604AP
OPA604APG4 ACTIVE PDIP P 8 50 Green (RoHS& no Sb/Br)
CU NIPDAU N / A for Pkg Type -40 to 85 OPA604AP
OPA604AU ACTIVE SOIC D 8 75 Green (RoHS& no Sb/Br)
CU NIPDAU Level-3-260C-168 HR -40 to 85 OPA604AU
OPA604AU/2K5 ACTIVE SOIC D 8 2500 Green (RoHS& no Sb/Br)
CU NIPDAU Level-3-260C-168 HR -40 to 85 OPA604AU
OPA604AU/2K5G4 ACTIVE SOIC D 8 2500 Green (RoHS& no Sb/Br)
CU NIPDAU Level-3-260C-168 HR -40 to 85 OPA604AU
OPA604AUE4 ACTIVE SOIC D 8 75 Green (RoHS& no Sb/Br)
CU 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) Eco Plan - The planned eco-friendly classification: Pb-Free (RoHS), Pb-Free (RoHS Exempt), or Green (RoHS & no Sb/Br) - please check http://www.ti.com/productcontent for the latest availabilityinformation and additional product content details.TBD: The Pb-Free/Green conversion plan has not been defined.Pb-Free (RoHS): TI's terms "Lead-Free" or "Pb-Free" mean semiconductor products that are compatible with the current RoHS requirements for all 6 substances, including the requirement thatlead not exceed 0.1% by weight in homogeneous materials. Where designed to be soldered at high temperatures, TI Pb-Free products are suitable for use in specified lead-free processes.Pb-Free (RoHS Exempt): This component has a RoHS exemption for either 1) lead-based flip-chip solder bumps used between the die and package, or 2) lead-based die adhesive used betweenthe die and leadframe. The component is otherwise considered Pb-Free (RoHS compatible) as defined above.Green (RoHS & no Sb/Br): TI defines "Green" to mean Pb-Free (RoHS compatible), and free of Bromine (Br) and Antimony (Sb) based flame retardants (Br or Sb do not exceed 0.1% by weightin homogeneous material)
(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 continuationof 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 finishvalue 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.
Texas Instruments Incorporated and its subsidiaries (TI) reserve the right to make corrections, enhancements, improvements and otherchanges to its semiconductor products and services per JESD46, latest issue, and to discontinue any product or service per JESD48, latestissue. Buyers should obtain the latest relevant information before placing orders and should verify that such information is current andcomplete. All semiconductor products (also referred to herein as “components”) are sold subject to TI’s terms and conditions of salesupplied at the time of order acknowledgment.TI warrants performance of its components to the specifications applicable at the time of sale, in accordance with the warranty in TI’s termsand conditions of sale of semiconductor products. Testing and other quality control techniques are used to the extent TI deems necessaryto support this warranty. Except where mandated by applicable law, testing of all parameters of each component is not necessarilyperformed.TI assumes no liability for applications assistance or the design of Buyers’ products. Buyers are responsible for their products andapplications using TI components. To minimize the risks associated with Buyers’ products and applications, Buyers should provideadequate design and operating safeguards.TI does not warrant or represent that any license, either express or implied, is granted under any patent right, copyright, mask work right, orother intellectual property right relating to any combination, machine, or process in which TI components or services are used. Informationpublished by TI regarding third-party products or services does not constitute a license to use such products or services or a warranty orendorsement thereof. Use of such information may require a license from a third party under the patents or other intellectual property of thethird party, or a license from TI under the patents or other intellectual property of TI.Reproduction of significant portions of TI information in TI data books or data sheets is permissible only if reproduction is without alterationand is accompanied by all associated warranties, conditions, limitations, and notices. TI is not responsible or liable for such altereddocumentation. Information of third parties may be subject to additional restrictions.Resale of TI components or services with statements different from or beyond the parameters stated by TI for that component or servicevoids all express and any implied warranties for the associated TI component or service and is an unfair and deceptive business practice.TI is not responsible or liable for any such statements.Buyer acknowledges and agrees that it is solely responsible for compliance with all legal, regulatory and safety-related requirementsconcerning its products, and any use of TI components in its applications, notwithstanding any applications-related information or supportthat may be provided by TI. Buyer represents and agrees that it has all the necessary expertise to create and implement safeguards whichanticipate dangerous consequences of failures, monitor failures and their consequences, lessen the likelihood of failures that might causeharm and take appropriate remedial actions. Buyer will fully indemnify TI and its representatives against any damages arising out of the useof any TI components in safety-critical applications.In some cases, TI components may be promoted specifically to facilitate safety-related applications. With such components, TI’s goal is tohelp enable customers to design and create their own end-product solutions that meet applicable functional safety standards andrequirements. Nonetheless, such components are subject to these terms.No TI components are authorized for use in FDA Class III (or similar life-critical medical equipment) unless authorized officers of the partieshave executed a special agreement specifically governing such use.Only those TI components which TI has specifically designated as military grade or “enhanced plastic” are designed and intended for use inmilitary/aerospace applications or environments. Buyer acknowledges and agrees that any military or aerospace use of TI componentswhich have not been so designated is solely at the Buyer's risk, and that Buyer is solely responsible for compliance with all legal andregulatory requirements in connection with such use.TI has specifically designated certain components as meeting ISO/TS16949 requirements, mainly for automotive use. In any case of use ofnon-designated products, TI will not be responsible for any failure to meet ISO/TS16949.
Products ApplicationsAudio www.ti.com/audio Automotive and Transportation www.ti.com/automotiveAmplifiers amplifier.ti.com Communications and Telecom www.ti.com/communicationsData Converters dataconverter.ti.com Computers and Peripherals www.ti.com/computersDLP® Products www.dlp.com Consumer Electronics www.ti.com/consumer-appsDSP dsp.ti.com Energy and Lighting www.ti.com/energyClocks and Timers www.ti.com/clocks Industrial www.ti.com/industrialInterface interface.ti.com Medical www.ti.com/medicalLogic logic.ti.com Security www.ti.com/securityPower Mgmt power.ti.com Space, Avionics and Defense www.ti.com/space-avionics-defenseMicrocontrollers microcontroller.ti.com Video and Imaging www.ti.com/videoRFID www.ti-rfid.comOMAP Applications Processors www.ti.com/omap TI E2E Community e2e.ti.comWireless Connectivity www.ti.com/wirelessconnectivity