OPA2604

® OPA 260 4 OPA2604 OPA 260 4 www.burr-brown.com/databook/OPA2604.html Dual FET-Input, Low Distortion OPERATIONAL AMPLIFIER FEATURES q LOW DISTORTION: 0.0003% at 1kHz q LOW NOISE: 10nV/√Hz q HIGH SLEW RATE: 25V/µs q WIDE GAIN-BANDWIDTH: 20MHz q UNITY-GAIN STABLE q WIDE SUPPLY RANGE: VS = ±4.5 to ±24V q DRIVES 600Ω LOADS APPLICATIONS q PROFESSIONAL AUDIO EQUIPMENT q PCM DAC I/V CONVERTER q SPECTRAL ANALYSIS EQUIPMENT q ACTIVE FILTERS q TRANSDUCER AMPLIFIER q DATA ACQUISITION DESCRIPTION The OPA2604 is a dual, 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 dynamic 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 OPA2604 provides wide dynamic range, even with high source impedance. Offset voltage is laser-trimmed to minimize the need for interstage coupling capacitors. The OPA2604 is available in 8-pin plastic mini-DIP and SO-8 surface-mount packages, specified for the –25°C to +85°C temperature range. * Patents Granted: #5053718, 5019789 (8) V+ (+) (3, 5) (–) (2, 6) Distortion Rejection Circuitry* Output Stage* (1, 7) VO (4) V– International Airport Industrial Park • Mailing Address: PO Box 11400, Tucson, AZ 85734 • Street Address: 6730 S. Tucson Blvd., Tucson, AZ 85706 • Tel: (520) 746-1111 • Twx: 910-952-1111 Internet: http://www.burr-brown.com/ • FAXLine: (800) 548-6133 (US/Canada Only) • Cable: BBRCORP • Telex: 066-6491 • FAX: (520) 889-1510 • Immediate Product Info: (800) 548-6132 ® © 1991 Burr-Brown Corporation 1 PDS-1069E Printed in U.S.A. October, 1997 OPA2604 SPECIFICATIONS ELECTRICAL At TA = +25 °C, VS = ±15V, unless otherwise noted. OPA2604AP, AU PARAMETER OFFSET VOLTAGE Input Offset Voltage Average Drift Power Supply Rejection INPUT BIAS CURRENT(1) Input Bias Current Input Offset Current NOISE Input Voltage Noise Noise Density: f = 10Hz f = 100Hz f = 1kHz f = 10kHz Voltage Noise, BW = 20Hz to 20kHz Input Bias Current Noise Current Noise Density, f = 0.1Hz to 20kHz INPUT VOLTAGE RANGE Common-Mode Input Range Common-Mode Rejection INPUT IMPEDANCE Differential Common-Mode OPEN-LOOP GAIN Open-Loop Voltage Gain FREQUENCY RESPONSE Gain-Bandwidth Product Slew Rate Settling Time: 0.01% 0.1% Total Harmonic Distortion + Noise (THD+N) Channel Separation OUTPUT Voltage Output Current Output Short Circuit Current Output Resistance, Open-Loop POWER SUPPLY Specified Operating Voltage Operating Voltage Range Current, Total Both Amplifiers TEMPERATURE RANGE Specification Storage Thermal Resistance(2), θJA VO = ±10V, RL = 1kΩ G = 100 20Vp-p, RL = 1kΩ G = –1, 10V Step G = 1, f = 1kHz VO = 3.5Vrms, RL = 1kΩ f = 1kHz, RL = 1kΩ RL = 600Ω VO = ±12V ±11 80 ±12 80 CONDITION MIN TYP ±1 ±8 80 100 ±4 MAX ±5 UNITS mV µV/°C dB pA pA VS = ±5 to ±24V VCM = 0V VCM = 0V 70 25 15 11 10 1.5 6 ±13 100 1012 || 8 1012 || 10 100 20 25 1.5 1 0.0003 142 ±12 ±35 ±40 25 ±15 ±10.5 nV/√Hz nV/√Hz nV/√Hz nV/√Hz µVp-p fA/√Hz V dB Ω || pF Ω || pF dB MHz V/µs µs µs % dB V mA mA Ω V V mA °C °C °C/W VCM = ±12V 15 ±4.5 IO = 0 –25 –40 ±24 ±12 +85 +125 90 NOTES: (1) Typical performance, measured fully warmed-up. (2) Soldered to circuit board—see text. The information provided herein is believed to be reliable; however, BURR-BROWN assumes no responsibility for inaccuracies or omissions. BURR-BROWN assumes no responsibility for the use of this information, and all use of such information shall be entirely at the user’s own risk. Prices and specifications are subject to change without notice. No patent rights or licenses to any of the circuits described herein are implied or granted to any third party. BURR-BROWN does not authorize or warrant any BURR-BROWN product for use in life support devices and/or systems. ® OPA2604 2 PIN CONFIGURATION Top View DIP/SOIC ABSOLUTE MAXIMUM RATINGS(1) Power Supply Voltage ....................................................................... ±25V Input Voltage ............................................................. (V–)–1V to (V+)+1V Output Short Circuit to Ground ............................................... Continuous Operating Temperature ................................................. –40° C to +100°C Storage Temperature ..................................................... –40° C to +125°C Junction Temperature .................................................................... +150°C Lead Temperature (soldering, 10s) AP ......................................... +300°C Lead Temperature (soldering, 3s) AU .......................................... +260°C NOTE: (1) Stresses above these ratings may cause permanent damage. Output A –In A +In A V– 1 2 3 4 8 7 6 5 V+ Output B –In B +In B ORDERING INFORMATION PRODUCT PACKAGE 8-Pin Plastic DIP SO-8 Surface-Mount TEMP. RANGE –25°C to +85°C –25°C to +85°C OPA2604AP OPA2604AU ELECTROSTATIC DISCHARGE SENSITIVITY Any integrated circuit can be damaged by ESD. Burr-Brown recommends that all integrated circuits be handled with appropriate precautions. Failure to observe proper handling and installation procedures can cause damage. ESD damage can range from subtle performance degradation to complete device failure. Precision integrated circuits may be more susceptible to damage because very small parametric changes could cause the device not to meet published specifications. PACKAGING INFORMATION PACKAGE DRAWING PRODUCT OPA2604AP OPA2604AU PACKAGE 8-Pin Plastic DIP SO-8 Surface-Mount NUMBER(1) 006 182 NOTE: (1) For detailed drawing and dimension table, please see end of data sheet, or Appendix C of Burr-Brown IC Data Book. ® 3 OPA2604 TYPICAL PERFORMANCE CURVES At TA = +25°C, VS = ±15V, unless otherwise noted. TOTAL HARMONIC DISTORTION + NOISE vs FREQUENCY 1 VO = 3.5Vrms 1kΩ TOTAL HARMONIC DISTORTION + NOISE vs OUTPUT VOLTAGE 0.1 See “Distortion Measurements” for description of test method. VO 1kΩ 0.1 THD + N (%) Measurement BW = 80kHz See “Distortion Measurements” for description of test method. THD + N (%) 0.01 f = 1kHz Measurement BW = 80kHz 0.001 0.01 G = 100V/V G = 10V/V 0.001 G = 1V/V 0.0001 20 100 1k Frequency (Hz) 10k 20k 0.0001 0.1 1 10 100 Output Voltage (Vp-p) OPEN-LOOP GAIN/PHASE vs FREQUENCY 120 100 80 60 40 G 20 0 –20 1 10 100 1k 10k 100k 1M 10M Frequency (Hz) –180 1 1 INPUT VOLTAGE AND CURRENT NOISE SPECTRAL DENSITY vs FREQUENCY 0 1k 1k φ –90 Phase Shift (Degrees) 100 Voltage Noise 100 –135 10 10 Current Noise 10 100 1k Frequency (Hz) 10k 100k 1 1M INPUT BIAS AND INPUT OFFSET CURRENT vs TEMPERATURE 100nA Input Bias Current 10nA INPUT BIAS AND INPUT OFFSET CURRENT vs INPUT COMMON-MODE VOLTAGE 10nA 1nA Input Offset Current (pA) Input Bias Current (pA) Input Bias Current (pA) 10nA 1nA 1nA Input Bias Current 100 1nA 100 100 Input Offset Current 10 10 100 Input Offset Current 10 –15 –10 –5 0 5 10 10 1 1 –75 –50 –25 0 25 50 75 100 0.1 125 1 15 Ambient Temperature (°C) Common-Mode Voltage (V) ® OPA2604 4 Input Offset Current (pA) Current Noise (fA/ Hz) –45 Voltage Gain (dB) Voltage Noise (nV/ Hz) TYPICAL PERFORMANCE CURVES At TA = +25°C, VS = ±15V, unless otherwise noted. (CONT) INPUT BIAS CURRENT vs TIME FROM POWER TURN-ON 1nA COMMON-MODE REJECTION vs COMMON-MODE VOLTAGE 120 Common-Mode Rejection (dB) VS = ±24VDC Input Bias Current (pA) 100 VS = ±15VDC 110 100 10 VS = ±5VDC 90 1 0 1 2 3 4 5 Time After Power Turn-On (min) 80 –15 –10 –5 0 5 10 15 Common-Mode Voltage (V) POWER SUPPLY AND COMMON-MODE REJECTION vs FREQUENCY 120 100 CMR AOL, PSR, AND CMR vs SUPPLY VOLTAGE 120 110 80 –PSR 60 40 20 0 10 +PSR AOL, PSR, CMR (dB) CMR 100 AOL PSR, CMR (dB) 90 80 PSR 70 100 1k 10k 100k 1M 10M 5 10 15 Supply Voltage (±VS) 20 25 Frequency (Hz) GAIN-BANDWIDTH AND SLEW RATE vs SUPPLY VOLTAGE 28 33 28 GAIN-BANDWIDTH AND SLEW RATE vs TEMPERATURE 30 Slew Rate Gain-Bandwidth (MHz) Gain-Bandwidth (MHz) 24 Slew Rate (V/µs) 20 25 20 Gain-Bandwidth G = +100 20 16 21 16 15 12 5 10 15 Supply Voltage (±VS) 20 17 25 12 –75 –50 –25 0 25 50 75 100 Temperature (°C) 10 125 Slew Rate (V/µs) ® Gain-Bandwidth G = +100 Slew Rate 29 24 25 5 OPA2604 TYPICAL PERFORMANCE CURVES At TA = +25°C, VS = ±15V, unless otherwise noted. (CONT) SETTLING TIME vs CLOSED-LOOP GAIN 5 VO = 10V Step RL = 1kΩ CL = 50pF 160 CHANNEL SEPARATION vs FREQUENCY RL = ∞ Channel Separation (dB) 4 Settling Time (µs) 140 RL = 1kΩ 120 3 0.01% 2 0.1% 1 100 A VO = 20Vp-p RL B Measured Output 0 –1 –10 –100 –1000 Closed-Loop Gain (V/V) 80 10 100 1k Frequency (Hz) 10k 100k MAXIMUM OUTPUT VOLTAGE SWING vs FREQUENCY 30 VS = ±15V Output Voltage (Vp-p) Supply Current (mA) SUPPLY CURRENT vs TEMPERATURE 14 Total for Both Op Amps 12 VS = ±15VDC VS = ±24VDC 10 20 VS = ±5VDC 10 8 0 10k 100k Frequency (Hz) 1M 10M 6 –75 –50 –25 0 25 50 75 100 125 Ambient Temperature (°C) LARGE-SIGNAL TRANSIENT RESPONSE SMALL-SIGNAL TRANSIENT RESPONSE Output Voltage (V) +10 30 FPO Bleed to edge –10 Output Voltage (mV) +100 25 Slew Rate (V/µs) –100 20 0 5 Time (µs) 10 0 1µs Time (µs) 2 µs 15 10 5 ® OPA2604 6 TYPICAL PERFORMANCE CURVES At TA = +25°C, VS = ±15V, unless otherwise noted. (CONT) SHORT-CIRCUIT CURRENT vs TEMPERATURE 60 ISC+ and ISC– 50 POWER DISSIPATION vs SUPPLY VOLTAGE 1 0.9 Worst case sine wave RL = 600Ω (both channels) Typical high-level music RL = 600Ω (both channels) Short-Circuit Current (mA) Power Dissipation (W) 0.8 0.7 0.6 0.5 0.4 0.3 0.2 40 30 No signal or no load 20 –75 –50 –25 0 25 50 75 100 125 Ambient Temperature (°C) 0.1 6 8 10 12 14 16 18 20 22 24 Supply Voltage, ±VS (V) MAXIMUM POWER DISSIPATION vs TEMPERATURE 1.4 Total Power Dissipation (W) 1.2 1.0 0.8 0.6 0.4 0.2 0 0 25 50 Maximum Specified Operating Temperature 85°C θJ-A = 90°C/W Soldered to Circuit Board (see text) 75 100 125 150 Ambient Temperature (°C) ® 7 OPA2604 APPLICATIONS INFORMATION The OPA2604 is unity-gain stable, making it easy to use in a wide range of circuitry. Applications with noisy or high impedance power supply lines may require decoupling capacitors close to the device pins. In most cases 1µF tantalum capacitors are adequate. DISTORTION MEASUREMENTS The distortion produced by the OPA2604 is below the measurement limit of virtually all commercially available equipment. A special test circuit, however, can be used to extend the measurement capabilities. Op amp distortion can be considered an internal error source which can be referred to the input. Figure 1 shows a circuit which causes the op amp distortion to be 101 times greater than normally produced by the op amp. The addition of R3 to the otherwise standard non-inverting amplifier configuration alters the feedback factor or noise gain of the circuit. The closed-loop gain is unchanged, but the feedback available for error correction is reduced by a factor of 101. This extends the measurement limit, including the effects of the signal-source purity, by a factor of 101. Note that the input signal and load applied to the op amp are the same as with conventional feedback without R3. Validity of this technique can be verified by duplicating measurements at high gain and/or high frequency where the distortion is within the measurement capability of the test equipment. Measurements for this data sheet were made with the Audio Precision System One which greatly simplifies such repetitive measurements. The measurement technique can, however, be performed with manual distortion measurement instruments. CAPACITIVE LOADS The dynamic characteristics of the OPA2604 have been optimized for commonly encountered gains, loads and operating conditions. The combination of low closed-loop gain and capacitive load will decrease the phase margin and may lead to gain peaking or oscillations. Load capacitance reacts with the op amp’s open-loop output resistance to form an additional pole in the feedback loop. Figure 2 shows various circuits which preserve phase margin with capacitive load. Request Application Bulletin AB-028 for details of analysis techniques and applications circuits. For the unity-gain buffer, Figure 2a, stability is preserved by adding a phase-lead network, RC and CC. Voltage drop across RC will reduce output voltage swing with heavy loads. An alternate circuit, Figure 2b, does not limit the output with low load impedance. It provides a small amount of positive feedback to reduce the net feedback factor. Input impedance of this circuit falls at high frequency as op amp gain rolloff reduces the bootstrap action on the compensation network. Figures 2c and 2d show compensation techniques for noninverting amplifiers. Like the follower circuits, the circuit in Figure 2d eliminates voltage drop due to load current, but at the penalty of somewhat reduced input impedance at high frequency. Figures 2e and 2f show input lead compensation networks for inverting and difference amplifier configurations. NOISE PERFORMANCE Op amp noise is described by two parameters—noise voltage and noise current. The voltage noise determines the noise performance with low source impedance. Low noise bipolarinput op amps such as the OPA27 and OPA37 provide very low voltage noise. But if source impedance is greater than a few thousand ohms, the current noise of bipolar-input op amps react with the source impedance and will dominate. At a few thousand ohms source impedance and above, the OPA2604 will generally provide lower noise. R1 R2 SIG. DIST. GAIN GAIN 1 R1 ∞ 500Ω 50Ω R2 5kΩ 5kΩ 5kΩ R3 50Ω 500Ω ∞ R3 2 1 VO = 10Vp-p (3.5Vrms) 10 100 101 101 101 OPA2604 Generator Output Analyzer Input Audio Precision System One Analyzer* RL 1kΩ IBM PC or Compatible * Measurement BW = 80kHz FIGURE 1. Distortion Test Circuit. ® OPA2604 8 (a) (b) CC 820pF 1 2 1 2 RC eo 750Ω CL 5000pF R2 ei 2kΩ OPA2604 CC 0.47µF RC 10Ω RC = CC = R2 4CL X 1010 – 1 CL X 103 RC eo CL 5000pF OPA2604 ei CC = 120 X 10–12 CL (c) R1 10kΩ R2 10kΩ CC 24pF 1 2 (d) R1 2kΩ RC 20Ω RC eo 25Ω CL 5000pF ei R2 2CL X 1010 – (1 + R2/R1) C L X 103 RC CL 5000pF CC 0.22µF 1 R2 2kΩ 2 OPA2604 ei 50 CL R2 OPA2604 eo CC = RC = CC = (e) R2 e1 2kΩ R1 ei 2kΩ RC 20Ω CC 0.22µF RC = R2 2CL X 1010 – (1 + R2/R1) RC = CC = CL X 103 RC 1 2 (f) R1 2kΩ RC 20Ω eo CC 0.22µF CL 5000pF e2 2kΩ 2kΩ R2 2C L X 1010 – (1 + R2/R1) C L X 103 RC R3 R2 2kΩ 1 2 OPA2604 OPA2604 eo CL 5000pF R4 CC = NOTE: Design equations and component values are approximate. User adjustment is required for optimum performance. FIGURE 2. Driving Large Capacitive Loads. ® 9 OPA2604 POWER DISSIPATION The OPA2604 is capable of driving 600Ω loads with power supply voltages up to ±24V. Internal power dissipation is increased when operating at high power supply voltage. The typical performance curve, Power Dissipation vs Power Supply Voltage, shows quiescent dissipation (no signal or no load) as well as dissipation with a worst case continuous sine wave. Continuous high-level music signals typically produce dissipation significantly less than worst case sine waves. Copper leadframe construction used in the OPA2604 improves heat dissipation compared to conventional plastic packages. To achieve best heat dissipation, solder the device directly to the circuit board and use wide circuit board traces. OUTPUT CURRENT LIMIT Output current is limited by internal circuitry to approximately ±40mA at 25°C. The limit current decreases with increasing temperature as shown in the typical curves. R4 22kΩ C3 R1 VIN 2.7kΩ 22kΩ C1 3000pF 10kΩ C2 2000pF fp = 20kHz R2 R3 1 2 100pF OPA2604 VO FIGURE 3. Three-Pole Low-Pass Filter. 1 2 R1 VIN 6.04kΩ R2 4.02kΩ R5 2kΩ OPA2604 VO C3 1000pF R2 4.02kΩ 1 2 1 2 OPA2604 OPA2604 Low-pass 3-pole Butterworth f–3dB = 40kHz C1 1000pF R4 5.36kΩ See Application Bulletin AB-026 for information on GIC filters. C2 1000pF FIGURE 4. Three-Pole Generalized Immittance Converter (GIC) Low-Pass Filter. ® OPA2604 10 C1* I-Out DAC R1 2kΩ 1 2 C2 2200pF R2 2.94kΩ R3 21kΩ C3 470pF 1 2 OPA2604 VO COUT OPA2604 ~ * C1 = COUT 2π R1 fc Low-pass 2-pole Butterworth f–3dB = 20kHz R1 = Feedback resistance = 2kΩ fc = Crossover frequency = 8MHz FIGURE 5. DAC I/V Amplifier and Low-Pass Filter. 1 7.87kΩ – 2 10kΩ 10kΩ OPA2604 1 2 VIN + 100pF OPA2604 VO G=1 1 7.87kΩ 100kHz Input Filter 2 OPA2604 10kΩ 10kΩ FIGURE 6. Differential Amplifier with Low-Pass Filter. ® 11 OPA2604 100Ω 10kΩ * C1 ≈ COUT 2π R f f c 1 2 G = 101 (40dB) Rf = Internal feedback resistance = 1.5kΩ fc = Crossover frequency = 8MHz 10 5 PCM63 20-bit 6 D/A 9 Converter C1* 1 2 OPA2604 Piezoelectric Transducer 1MΩ* * Provides input bias current return path. OPA2604 VO = ±3Vp To low-pass filter. FIGURE 7. High Impedance Amplifier. FIGURE 8. Digital Audio DAC I-V Amplifier. 1/2 OPA2604 A2 I2 R4 R3 51Ω A1 VIN R2 i1 IL = I1 + I2 51Ω 1/2 OPA2604 VOUT R1 VOUT = VIN (1 + R2/R1) Load FIGURE 9. Using the Dual OPA2604 Op Amp to Double the Output Current to a Load. ® OPA2604 12