® OPA502 High Current, High Power OPERATIONAL AMPLIFIER FEATURES APPLICATIONS ● HIGH OUTPUT CURRENT: 10A ● MOTOR DRIVER ● WIDE POWER SUPPLY VOLTAGE: ±10V to ±45V ● USER-SET CURRENT LIMIT ● SERVO AMPLIFIER ● PROGRAMMABLE POWER SUPPLY ● ACTUATOR DRIVER ● SLEW RATE: 10V/µs ● FET INPUT: IB = 200pA max ● CLASS A/B OUTPUT STAGE ● AUDIO AMPLIFIER ● TEST EQUIPMENT ● QUIESCENT CURRENT: 25mA max ● HERMETIC TO-3 PACKAGE — ISOLATED CASE V+ 3 DESCRIPTION The OPA502 is a high output current operational amplifier designed to drive a wide range of resistive and reactive loads. Its complementary class A/B output stage provides superior performance in applications requiring freedom from crossover distortion. Resistor-programmable current limits provide protection for both the amplifier and the load during abnormal operating conditions. An adjustable foldover current limit can also be used to protect against potentially damaging conditions. 5 280Ω 2 +Output Drive 1 Current Sense 4 20kΩ Bias Circuit 20kΩ The OPA502 employs a custom monolithic op amp/ driver circuit and rugged complementary output transistors, providing excellent DC and dynamic performance. The industry-standard 8-pin TO-3 package is electrically isolated from all circuitry. This allows the OPA502 to be mounted directly to a heat sink without cumbersome insulating hardware which degrade thermal performance. The OPA502 is available in –40°C to +85°C temperature range. 280Ω 6 7 8 RFO – Output Drive 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 ® © 1992 Burr-Brown Corporation PDS-1166B 1 Printed in U.S.A. March, 1998 OPA502 SPECIFICATIONS TCASE = +25°C, VS = ±40V, unless otherwise noted. OPA502BM PARAMETER CONDITION OFFSET VOLTAGE Input Offset Voltage vs Temperature vs Power Supply Specified Temp. Range VS = ±10V to ±45V MIN TYP MAX UNITS ±5 74 ±0.5 ±5 92 mV µV/°C dB 200 pA pA INPUT BIAS CURRENT(1) Input Bias Current Input Offset Current VCM = 0V VCM = 0V 12 ±3 NOISE Input Voltage Noise Noise Density, Current Noise Density, f = 1kHz f = 1kHz 25 3 nV/√Hz fA/√Hz (V+) –4 (V–) +4 106 V V dB 1012 || 5 1012 || 4 Ω || pF Ω || pF 103 dB 2.0 10 See Typical Curves 0.06 MHz V/µs INPUT VOLTAGE RANGE Common-Mode Input Range, Positive Negative Common-Mode Rejection Linear Operation Linear Operation VCM = ±35V (V+) –5 (V–) +5 74 INPUT IMPEDANCE Differential Common-Mode OPEN-LOOP GAIN Open-Loop Voltage Gain FREQUENCY RESPONSE Gain-Bandwidth Product Slew Rate Full-Power Bandwidth Total Harmonic Distortion VO = ±34V, RL = 6Ω 92 G = +10, RL = 50Ω 68Vp-p, RL = 6Ω 5 G = +3, f = 20kHz VO = 20V, RL = 8Ω Capacitive Load % See Figure 6 OUTPUT Voltage Output, Positive Negative Positive Negative Current Output Short Circuit Current POWER SUPPLY Specified Operating Voltage Operating Voltage Range Quiescent Current TEMPERATURE RANGE Specification Storage Thermal Resistance, θJC θJA IO = 10A IO = 10A IO = 1A IO = 1A (V+) –6 (V–) +6 ±10 IO = 0 (V+)–3.5 (V–) +3.6 (V+) –2.5 (V–) +3.1 See SOA Curves Resistor Programmed ±40 ±20 –40 –55 DC AC f ≥ 50Hz No Heat Sink 1.25 0.8 30 V V V V ±45 ±25 +85 +125 1.4 0.9 V V mA °C °C °C/W °C/W °C/W NOTE: (1) High-speed test at TJ = 25°C. ABSOLUTE MAXIMUM RATINGS(1) PACKAGE/ORDERING INFORMATION Supply Voltage, V+ to V– ..................................................................... 90V Output Current .................................................................. See SOA Curve Input Voltage .............................................................. (V–) –1V to (V+)+1V Case Temperature, Operating ......................................................... 150°C Junction Temperature ...................................................................... 200°C PRODUCT PACKAGE PACKAGE DRAWING NUMBER(1) OPA502BM 8-Pin TO-3 030 TEMPERATURE RANGE –40°C to +85°C NOTE: (1) For detailed drawing and dimension table, please see end of data sheet, or Appendix C of Burr-Brown IC Data Book. NOTE: (1) Stresses above these ratings may cause permanent damage. 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. ® OPA502 2 ELECTROSTATIC DISCHARGE SENSITIVITY PIN CONFIGURATION Top View TO-3 V+ 2 3 +Output Drive 1 +In This 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. + RCL Current Sense VO 4 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 its published specifications. – –In RCL 5 8 6 –Output Drive 7 V– RFO TYPICAL PERFORMANCE CURVES TCASE = +25°C, VS = ±40V, unless otherwise noted. CURRENT LIMIT vs TEMPERATURE CURRENT LIMIT vs LIMIT RESISTOR 2.4 0.24 2.2 0.22 RCL = 5.0Ω 1 ICL (A) ICL (A) 2.0 –ICL +ICL 0.20 1.8 0.18 1.6 0.16 RCL = 0.5Ω 1.4 0.14 NOTE: These are average values. –ICL is typically 8% higher. +ICL is typically 8% lower. 1.2 0.01 0.10 1 0.10 –50 10 –25 0 OPEN-LOOP GAIN AND PHASE vs FREQUENCY 50 75 100 125 SUPPLY CURRENT vs TEMPERATURE 100 –45 80 –90 –135 RL = 50Ω 40 –180 30 Supply Current (mA) 0 Phase (degrees) 120 60 25 Case Temperature (°C) RCL (Ω) Voltage Gain (dB) 0.12 1.0 0.10 ICL (A) 10 20 VS = ±10 to ±45V RL = 4Ω 20 0 10 10 100 1k 10k 100k 1M 10M –50 Frequency (Hz) –25 0 25 50 75 100 125 Case Temperature (°C) ® 3 OPA502 TYPICAL PERFORMANCE CURVES (CONT) TCASE = +25°C, VS = ±40V, unless otherwise noted. INPUT BIAS CURRENT vs INPUT COMMON-MODE VOLTAGE INPUT BIAS AND OFFSET CURRENTS vs TEMPERATURE 2.2 1.8 1nA Normalized (IB) Input Bias and Offset Current (pA) 10nA IB 100 IOS 10 1.4 1.0 0.6 0.2 1 –50 –25 0 25 50 75 100 –40 125 –30 –20 –10 10 0 VOLTAGE NOISE DENSITY vs FREQUENCY 40 2.8 RL = 10kΩ 2.4 2.0 1k GBWP (MHz) Voltage Noise (nV/ Hz) 30 GAIN BANDWIDTH PRODUCT vs TEMPERATURE 10k 100 RL = 50Ω 1.6 G = +10 1.2 0.8 RL = 4Ω 0.4 10 0 1 10 100 10k 1k 100k –50 –25 Frequency (Hz) 0 50 25 75 100 125 Case Temperature (°C) POWER SUPPLY REJECTION vs FREQUENCY COMMON-MODE REJECTION vs FREQUENCY 120 120 100 100 CMRR (dB) PSRR (dB) 20 Common-Mode Voltage (V) Case Temperature (°C) 80 60 40 80 60 40 20 20 1 10 100 1k 10k 100k 1M 1 Frequency (Hz) 100 1k Frequency (Hz) ® OPA502 10 4 10k 100k 1M TYPICAL PERFORMANCE CURVES (CONT) TCASE = +25°C, VS = ±40V, unless otherwise noted. FULL POWER RESPONSE SLEW RATE vs TEMPERATURE 35 14 30 Output Voltage (VPK) Slew Rate (V/µs) 12 –SR 10 8 G = +10 VO = 34VPK RL = 6Ω 6 +SR 25 20 15 G = +10 RL = 8Ω THD < 2% 10 5 0 4 –50 –25 0 25 50 75 100 10k 125 100k TOTAL HARMONIC DISTORTION AND NOISE vs FREQUENCY OUTPUT VOLTAGE SWING vs OUTPUT CURRENT 1.000 5 0.100 4 PO = 100mW PO = 5W |±VS| – |VOUT| (V) G = +3 RL = 8Ω Measurement BW = 80kHz PO = 50W 0.010 (+VS) – VO 3 |–VS| – |VO| 2 1 0.001 0 20 100 10k 20k 1k 0 1 2 3 Frequency (Hz) 4 5 6 7 8 9 10 IOUT (A) OUTPUT VOLTAGE SWING vs TEMPERATURE 5 IO = +10A 4 |±VS| – |VO| (V) THD + N (%) 1M Frequency (Hz) Case Temperature (°C) IO = +1A 3 2 IO = –10A IO = –1A 1 0 –50 –25 0 25 50 75 100 125 Case Temperature (°C) ® 5 OPA502 TYPICAL PERFORMANCE CURVES (CONT) TCASE = +25°C, VS = ±40V, unless otherwise noted. SMALL SIGNAL RESPONSE G = +3, CL = 1000pF LARGE SIGNAL RESPONSE G = +3, RL = 4Ω APPLICATIONS INFORMATION +40V Power supply terminals should be bypassed with low series impedance capacitors such as ceramic or tantalum close to the device pins. Power supply wiring should have low series impedance and inductance. Figure 1 indicates the high current connections in bold lines. 2µF R1 R2 + RCL Current limit is set with two external resistors—one for positive output current and one for negative output current (see Figure 1). For conventional current limit, independent of output voltage, pin 7 should be left open (see “Foldback Current Limit”). Limiting occurs when the output current causes sufficient voltage drop across RCL to turn on the respective current limit transistor. The limit current decreases at high temperature (see typical performance curve “Current Limit vs Temperature). 5 4 VIN OPA502 1 8 R2 R1 VO – RCL 6 2µF Load 0.1µF NOTE: Bold lines indicate high current paths. –40V The current limit resistors can be chosen from a variety of types. Most common wire-wound types are satisfactory, although some physically large types may have excessive inductance which can cause problems. You should test your circuits with the exact resistor type planned for production use. G=1+ 3 2 Figure 1 also shows nominal current limit produced by standard resistor values. See also the typical performance curve “Current Limit vs Limit Resistance”. The output current must flow through this resistor, so its power rating must be chosen accordingly. The table in Figure 1 shows the power dissipation of the current limit resistor during continuous current limit (room temperature). Connections from the current limit resistors to the device pins can typically add 0.02Ω to 0.05Ω to the effective value of RCL. This significantly affects the current limit value for high output currents. RCL (Ω) ICL at 25°C (A) Power Dissipation1 of RCL (W) 10 5 2 1 0.68 0.5 0.3 0.2 0.15 0.1 0.11 0.19 0.44 0.78 1.22 1.65 2.73 4.0 5.4 8.1 0.12 0.18 0.39 0.61 1.0 1.4 2.2 3.2 4.4 6.6 NOTE 1: Power dissipation during continuous current limit at TCASE = +25°C. FIGURE 1. Basic Circuit Connections. You can set different current limits for positive and negative current. Resistors are chosen with the same table of values in Figure 1. tor. The power dissipated by the output transistor is equal to the product of the output current and the voltage across the conducting transistor, VCE. The Safe Operating Area (SOA curve, Figure 2) shows the permissible range of voltage and current. SAFE OPERATING AREA Stress on the output transistors is determined by the output current and the voltage across the conducting output transis® OPA502 0.1µF 6 circuit can be set to allow high output current when VCE is low (high output voltage). Output current limits at a lower value under the more stressful condition when VCE is high, (output voltage is low). The safe output current decreases as VCE increases. Output short-circuits are a very demanding case for SOA. A shortcircuit to ground forces the full power supply voltage (V+ or V–) across the conducting transistor. With VS = ±40V the current limit must be set for 3A (25°C) to be safe for continuous short-circuit to ground. For further insight on SOA, consult AB-039. The behavior of this voltage-dependant current limit is described by the following equation. 0.81 + ILIMIT = SAFE OPERATING AREA 10 t= t= TC = +25°C m 0.5 s 1m 5.0 TC = +85°C where: VO is the output voltage measured with respect to ground. s t= s IO (A) RFO is the resistor connected from pin 7 to ground (in k ohms). 5m 2.0 0.28 VO RFO + 20 + 0.03 RCL 1.0 RCL is the current limit resistor (in ohms). 0.5 Ther mal Limitation (TJ = 200°C) 0.2 The foldover limit circuitry can be set to allow large voltage and current to resistive loads, yet limit output current to a safe value with an output short circuit. Second Breakdown Limited 0.1 1 2 5 10 20 50 100 Reactive or EMF-generating loads can produce unexpected behavior with the foldover circuit driven into limiting. With a reactive load, peak output current occurs at low or zero output voltage. Compared to a resistive load, a reactive load with the same total impedance will be more likely to activate the foldover limit circuitry. |VS – VOUT| (V) FIGURE 2. Safe Operating Area (SOA). UNBALANCED POWER SUPPLIES Some applications do not require equal positive and negative output voltage swing. The power supply voltages of the OPA502 do not need to be equal. Figure 3 shows a circuit designed for a positive output voltage and current. The –5V power supply voltage assures that the inputs of the OPA502 are operated within their linear common-mode range. The V+ power supply could range from 15V to 85V. The total voltage (V– to V+) can range from 20V to 90V. V+ Fast Recovery Diode 5A, 100V MR821 OPA502 55V at 0.5A MR821 9kΩ 1kΩ V– 2Ω VIN FIGURE 4. Diode Protection of Output. 0 to 50V VO OPA502 22Ω 0 to 5V Inductive or EMF-Generating Load OUTPUT PROTECTION The output stage of the OPA502 is protected by internal diode clamps to the power supply terminals. These internal diodes are similar to common silicon rectifier types and may not be fast enough for adequate protection. For loads that can deliver large reverse kickback current (greater than 5A) to the output, external fast-recovery clamp diodes are recommended (Figure 4). For these diodes (internal or external) to provide the intended protection, the power supplies must provide a low impedance to a reverse current. 0.5A RL –5V at 50mA FIGURE 3. Unbalanced Power Supplies. FOLDOVER CURRENT LIMIT By connecting a resistor from pin 7 to ground, you can make the limit current vary with output voltage. The foldover limit ® 7 OPA502 MOUNTING AND HEAT SINKING Most applications require a heat sink to assure that the maximum junction temperature is not exceeded. The heat sink required depends on the power dissipated and on ambient conditions. Consult Application Bulletin AB-038 for information on determining heat sink requirements. COMPENSATION AND STABILITY Capacitance at the inverting input causes a high frequency pole in the feedback path. This reduces phase margin, causing pulse response ringing, and in severe cases, oscillations. A low value feedback capacitor can reduce or eliminate this effect by maintaining a constant feedback factor at high frequency (see Figure 5). The case of the OPA502 is isolated from all circuitry and can be fastened directly to a heat sink. This eliminates cumbersome insulating hardware that degrades thermal performance. Consult Application Bulletin AB-037 for proper mounting techniques and procedures for TO-3 power products. Depending on the load conditions, precautions may be required when using the OPA502 in low gains. Gains less than +3V/V or –2V/V may cause oscillations, particularly with capacitive loads. Figure 6 shows several circuits for low gain and capacitive loads. SOCKET Large value feedback capacitors used to limit the closed-loop bandwidth or form an integrator may also produce instability because the closed-loop gain approaches unity at high frequency. C2 = A mating socket, 0804MC is available for the OPA502 and can be purchased from Burr-Brown. Although not required, this socket makes interchanging parts easy, especially during design and testing. R1 C R2 IN R2 R1 OPA502 CIN CIN = Input capacitance, package and wiring ≈ 20pF FIGURE 5. Compensating Input Capacitance. ® OPA502 8 10kΩ 20kΩ VIN 470pF 10kΩ OPA502 CL ≤ 0.01µF G = –2 10kΩ 20kΩ VIN 4µH 10Ω OPA502 CL ≤ 0.1µF G = –2 Prevents phase-inversion in G = 1 circuits IN4148 20kΩ OPA502 VIN 10kΩ 470pF CL ≤ 2200pF G = +1 FIGURE 6. Compensation Circuits. ® 9 OPA502 20kΩ 10kΩ 10pF G = +21 47pF 10Ω 0.1Ω OPA502 VIN VS = ±15V 4.7kΩ 100kΩ 4µH 0.1Ω OPA27 VS = ±40V 1kΩ 4Ω THD at 50W 0.02% at 20kHz 0.002% at 1kHz FIGURE 7. Low Distortion Composite Amplifier. +35V +35V 10kΩ 10kΩ 10kΩ 20kΩ 0.2Ω 0.2Ω 3nF 20Ω OPA502 OPA502 0.2Ω VIN 1kΩ 0.2Ω Load ±10V 120Vp-p (±60V) G = +3 G = –1 –35V –35V FIGURE 8. Bridge Drive Circuit. +30V 10V REF102 +30V 20kΩ +5V 20pF 8-bit data port (8 + 4 bits) 40kΩ 0-1mA 0.1Ω 10kΩ 10kΩ OPA602 4.7kΩ DAC7801 12-bit M-DAC OPA502 0.1Ω 470pF –30V FIGURE 9. Digitally Programmable Power Supply. ® OPA502 10 VO ±20V at 5A