OPA541

® OPA541 High Power Monolithic OPERATIONAL AMPLIFIER FEATURES q POWER SUPPLIES TO ±40V q OUTPUT CURRENT TO 10A PEAK q PROGRAMMABLE CURRENT LIMIT q INDUSTRY-STANDARD PIN OUT q FET INPUT q TO-3 AND LOW-COST POWER PLASTIC PACKAGES APPLICATIONS q MOTOR DRIVER q SERVO AMPLIFIER q SYNCHRO EXCITATION q AUDIO AMPLIFIER q PROGRAMMABLE POWER SUPPLY DESCRIPTION The OPA541 is a power operational amplifier capable of operation from power supplies up to ±40V and delivering continuous output currents up to 5A. Internal current limit circuitry can be user-programmed with a single external resistor, protecting the amplifier and load from fault conditions. The OPA541 is fabricated using a proprietary bipolar/FET process. Pinout is compatible with popular hybrid power amplifiers such as the OPA511, OPA512 and the 3573. The OPA541 uses a single current-limit resistor to set both the positive and negative current limits. Applications currently using hybrid power amplifiers requiring two current-limit resistors need not be modified. The OPA541 is available in an 11-pin power plastic package and an industry-standard 8-pin TO-3 hermetic package. The power plastic package has a copper-lead frame to maximize heat transfer. The TO-3 package is isolated from all circuitry, allowing it to be mounted directly to a heat sink without special insulators. +VS –In +In Current Sense R CL Output Drive External VO –VS 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 ® PDS-737H 1 OPA541 SPECIFICATIONS ELECTRICAL At TC= +25°C and VS = ±35VDC, unless otherwise noted. OPA541AM/AP PARAMETER INPUT OFFSET VOLTAGE VOS vs Temperature vs Supply Voltage vs Power INPUT BIAS CURRENT IB INPUT OFFSET CURRENT IOS Specified Temperature Range INPUT CHARACTERISTICS Common-Mode Voltage Range Common-Mode Rejection Input Capacitance Input Impedance, DC GAIN CHARACTERISTICS Open Loop Gain at 10Hz Gain-Bandwidth Product OUTPUT Voltage Swing Specified Temperature Range VCM = (|±VS| – 6V) ±(|VS| – 6) 95 ±(|VS| – 3) 113 5 1 97 1.6 ±(|VS| – 4.5) ±(|VS| – 3.6) ±(|VS| – 3.2) 10 10 55 2 SOA(1) 40 ±10 ±30 20 2.5 3 40 40 –25 +85 T –55 T +125 ±35 25 T T ±35 T ±40 T CONDITIONS MIN TYP ±2 ±20 ±2.5 ±20 4 ±1 MAX ±10 ±40 ±10 ±60 50 ±30 5 T T OPA541BM/SM MIN TYP ±0.1 ±15 T T T T T T T T T T T T T T T T T T T T MAX ±1 ±30 T T T T UNITS mV µV/°C µV/V µV/W pA pA nA V dB pF TΩ dB MHz V V V A V/µs kHz µs nF Degrees V mA °C/W °C/W °C/W °C/W °C °C Specified Temperature Range VS = ±10V to ±VMAX RL = 6 Ω 90 T IO = 5A, Continuous IO = 2A IO = 0.5A Current, Peak AC PERFORMANCE Slew Rate Power Bandwidth Settling Time to 0.1% Capacitive Load Phase Margin POWER SUPPLY Power Supply Voltage, ±VS Current, Quiescent THERMAL RESISTANCE θJC (Junction-to-Case)(2) θJC(2) θJA (Junction-to-Ambient) OPA541AP (Plastic) TEMPERATURE RANGE TCASE ±(|VS| – 5.5) ±(|VS| – 4.5) ±(|VS| – 4) 9 6 45 3.3 T T T T T T RL = 8Ω, VO = 20Vrms 2V Step Specified Temperature Range, G = 1 Specified Temperature Range, G >10 Specified Temperature Range, RL = 8Ω Specified Temperature Range AC Output f > 60Hz DC Output No Heat Sink AM, BM, AP SM T Specification same as OPA541AM/AP. NOTE: (1) SOA is the Safe Operating Area shown in Figure 1. (2) Plastic package may require insulator which typically adds 1°C/W. 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. ® OPA541 2 CONNECTION DIAGRAMS Top View TO–3 Plastic Package Tab at –VS +VS 3 +In 4 NC 2 1 Current Sense –In 5 8 6 –VS 7 NC Output Drive RCL 2 4 3 5 6 NC Output Drive 7 8 9 NC Current Sense RCL VO 10 11 VO 1 +In –In –VS +VS ABSOLUTE MAXIMUM RATINGS Supply Voltage, +VS to –VS ............................................................... 80V Output Current ............................................................................. see SOA Power Dissipation, Internal(1) ........................................................... 125W Input Voltage: Differential .................................................................... ±VS Common-mode ............................................................. ±VS Temperature: Pin solder, 10s ........................................................ +300°C Junction(1) ............................................................... +150°C Temperature Range: AM, BM SM Storage .................................................................... –65°C to +150°C Operating (case) ...................................................... –55°C to +125°C AP Storage ...................................................................... –40°C to +85°C Operating (case) ........................................................ –25°C to +85°C NOTE: (1) Long term operation at the maximum junction temperature will result in reduced product life. Derate internal power dissipation to achieve high MTTF. ORDERING INFORMATION PRODUCT OPA541AP OPA541AM OPA541BM OPA541SM PACKAGE Power Plastic TO-3 TO-3 TO-3 TEMPERATURE RANGE –25 °C to +85°C –25 °C to +85°C –25 °C to +85°C –55°C to +125°C CONTINUOUS CURRENT 5A 5A 5A 5A at at at at 25°C 25°C 25°C 25°C PACKAGE INFORMATION PRODUCT OPA541AP OPA541AM OPA541BM OPA541SM PACKAGE Power Plastic TO-3 TO-3 TO-3 PACKAGE DRAWING NUMBER(1) 242 030 030 030 NOTE: (1) For detailed drawing and dimension table, please see end of data sheet, or Appendix C of Burr-Brown IC Data Book. ELECTROSTATIC DISCHARGE SENSITIVITY 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. 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. ® 3 OPA541 TYPICAL PERFORMANCE CURVES At TA = +25°C, VS = ±35VDC, unless otherwise noted. INPUT BIAS CURRENT vs TEMPERATURE 100 110 90 OPEN-LOOP GAIN AND PHASE vs FREQUENCY Input Bias Current (nA) 10 Voltage Gain (dB) 70 50 30 10 1 Z L = 3.3nF Gain Z L = 2k Ω –135 –180 0.1 0.01 Z L = 3.3nF 0.001 –25 –10 0 25 50 75 100 125 1 10 100 1k 10k 100k 1M 10M Temperature (°C) Frequency (Hz) NORMALIZED QUIESCENT CURRENT vs TOTAL POWER SUPPLY VOLTAGE 1.3 1.2 6 5 OUTPUT VOLTAGE SWING vs OUTPUT CURRENT |±VS | – |VOUT | (V) Normalized IQ 1.1 TC = –25°C 1 0.9 0.8 0.7 0.6 20 30 40 50 60 70 80 90 +V S + |–VS | (V) TC = +125°C TC = +25°C (+VS ) – VO 4 3 2 1 0 0 1 2 3 4 5 IOUT (A) 6 7 8 9 10 |–VS | – |VO | VOLTAGE NOISE DENSITY vs FREQUENCY 1k 10 TOTAL HARMONIC DISTORTION + NOISE vs FREQUENCY Voltage Noise Density (nV/√Hz) 1 THD + Noise (%) P = 100mW O 0.1 P = 5W O PO = 50W A V = –5 100 0.01 10 1 10 100 1k 10k 100k Frequency (Hz) 0.001 10 100 1k Frequency (Hz) 10k 100k ® OPA541 4 Phase (Degrees) Phase Z L = 2k Ω 0 –45 –90 TYPICAL PERFORMANCE CURVES At TA = +25°C, VS = ±35VDC, unless otherwise noted. (CONT) CURRENT LIMIT vs RESISTANCE LIMIT 10 Power Plastic TO-3 10 CURRENT LIMIT vs RESISTANCE LIMIT vs TEMPERATURE Power Plastic at –25°C Power Plastic at +85°C TO-3 at –25°C TO-3 at +85°C ILIMIT (A) ILIMIT (A) 1 1 NOTE: These are averaged values. –I OUT is typically 10% higher. +I OUT is typically 10% lower. 0.1 0.01 0.1 0.01 NOTE: These are averaged values. –I OUT is typically 10% higher. +I OUT is typically 10% lower. 0.1 R CL (Ω ) 1 10 0.1 R CL (Ω ) 1 10 COMMON-MODE REJECTION vs FREQUENCY 120 110 100 DYNAMIC RESPONSE 90 80 70 60 50 10 100 1k 10k 100k 1M Voltage (2V/division) CMRR (dB) Time (1µs/division) Frequency (Hz) ® 5 OPA541 INSTALLATION INSTRUCTIONS POWER SUPPLIES The OPA541 is specified for operation from power supplies up to ±40V. It can also be operated from unbalanced power supplies or a single power supply, as long as the total power supply voltage does not exceed 80V. The power supplies should be bypassed with low series impedance capacitors such as ceramic or tantalum. These should be located as near as practical to the amplifier’s power supply pins. Good power amplifier circuit layout is, in general, like good high frequency layout. Consider the path of large power supply and output currents. Avoid routing these connections near low-level input circuitry to avoid waveform distortion and oscillations. CURRENT LIMIT Internal current limit circuitry is controlled by a single external resistor, RCL. Output load current flows through this external resistor. The current limit is activated when the voltage across this resistor is approximately a base-emitter turn-on voltage. The value of the current limit resistor is approximately: 0.809 – 0.057 (AM, BM, SM) RCL = | ILIM| (AP) RCL = 0.813 – 0.02 | ILIM| Sinusoidal outputs create dissipation according to rms load current. For the same RCL, AC peaks would still be limited to 5A, but rms current would be 3.5A, and a current limiting resistor with a lower power rating could be used. Some applications (such as voice amplification) are assured of signals with much lower duty cycles, allowing a current resistor with a low power rating. Wire-wound resistors may be used for RCL. Some wire-wound resistors, however, have excessive inductance and may cause loop-stability problems. Be sure to evaluate circuit performance with resistor type planned for production to assure proper circuit operation. HEAT SINKING Power amplifiers are rated by case temperature, not ambient temperature as with signal op amps. Sufficient heat sinking must be provided to keep the case temperature within rated limits for the maximum ambient temperature and power dissipation. The thermal resistance of the heat sink required may be calculated by: θ HS = TCASE – TAMBIENT PD (max) Commercially available heat sinks often specify their thermal resistance. These ratings are often suspect, however, since they depend greatly on the mounting environment and air flow conditions. Actual thermal performance should be verified by measurement of case temperature under the required load and environmental conditions. No insulating hardware is required when using the TO-3 package. Since mica and other similar insulators typically add approximately 0.7°C/W thermal resistance, their elimination significantly improves thermal performance. See BurrBrown Application Bulletin AB-038 for further details on heat sinking. On the power plastic package, the metal tab is connected to –VS , and appropriate actions should be taken when mounting on a heat sink or chassis. SAFE OPERATING AREA The safe operating area (SOA) plot provides comprehensive information on the power handling abilities of the OPA541. It shows the allowable output current as a function of the voltage across the conducting output transistor (see Figure 1). This voltage is equal to the power supply voltage minus the output voltage. For example, as the amplifier output swings near the positive power supply voltage, the voltage across the output transistor decreases and the device can safely provide large output currents demanded by the load. Because of the internal structure of the OPA541, the actual current limit depends on whether current is positive or negative. The above RCL gives an average value. For a given RCL, +IOUT will actually be limited at about 10% below the expected level, while –IOUT will be limited about 10% above the expected level. The current limit value decreases with increasing temperature due to the temperature coefficient of a base-emitter junction voltage. Similarly, the current limit value increases at low temperatures. Current limit versus resistor value and temperature effects are shown in the Typical Performance Curves. Approximate values for RCL at other temperatures may be calculated by adjusting RCL as follows: ∆ RCL = –2mV x (T – 25) | ILIM| The adjustable current limit can be set to provide protection from short circuits. The safe short-circuit current depends on power supply voltage. See the discussion on Safe Operating Area to determine the proper current limit value. Since the full load current flows through RCL, it must be selected for sufficient power dissipation. For a 5A current limit on the TO-3 package, the formula yields an RCL of 0.105Ω (0.143Ω on the power plastic package due to different internal resistances). A continuous 5A through 0.105Ω would require an RCL that can dissipate 2.625W. ® OPA541 6 SAFE OPERATING AREA 10 TC = +25°C TC = +85°C APPLICATIONS CIRCUITS +VS 10µF 0.1µF |IO | (A) 1 TC = +125°C “M” Package only D1 OPA541 AP, AM BM, SM 0.1 1 10 |V S – VOUT | (V) 100 0.1µF 10µF D2 L Inductive or EMF-Generating Load D1 – D2 : IN4003 –VS FIGURE 1. Safe Operating Area. Short circuit protection requires evaluation of SOA. When the amplifier output is shorted to ground, the full power supply voltage is impressed across the conducting output transistor. The current limit must be set to a value which is safe for the power supply voltage used. For instance, with VS ±35V, a short to ground would force 35V across the conducting power transistor. A current limit of 1.8A would be safe. Reactive, or EMF-generating, loads such as DC motors can present difficult SOA requirements. With a purely reactive load, output voltage and load current are 90° out of phase. Thus, peak output current occurs when the output voltage is zero and the voltage across the conducting transistor is equal to the full power supply voltage. See Burr-Brown Application Bulletin AB-039 for further information on evaluating SOA. REPLACING HYBRID POWER AMPLIFIERS The OPA541 can be used in applications currently using various hybrid power amplifiers, including the OPA501, OPA511, OPA512, and 3573. Of course, the application must be evaluated to assure that the output capability and other performance attributes of the OPA541 meet the necessary requirement. These hybrid power amplifiers use two current limit resistors to independently set the positive and negative current limit value. Since the OPA541 uses only one current limit resistor to set both the positive and negative current limit, only one resistor (see Figure 4) need be installed. If installed, the resistor connected to pin 2 (TO-3 package) is superfluous, but it does no harm. Because one resistor carries the current previously carried by two, the resistor may require a higher power rating. Minor adjustments may be required in the resistor value to achieve the same current limit value. Often, however, the change in current limit value when changing models is small compared to its variation over temperature. Many applications can use the same current limit resistor. FIGURE 2. Clamping Output for EMF-Generating Loads. R2 20pF 100k Ω R1 10kΩ VIN OPA541 Master 10kΩ L 0.1Ω A V = –R2 /R1 = –10 20pF OPA541 Slave 0.1Ω FIGURE 3. Isolating Capacitive Loads. RCL + 2 OPA501 8 1 RCL – 2 Not Required OPA541 8 1 RCL Pin 2 is “open” on OPA541. FIGURE 4. Replacing OPA501 with OPA541. ® 7 OPA541 +35V 0.1µF R2 10kΩ 30pF +60V 0.1µF 25kΩ 0–2mA DAC80-CBI-I VO OPA541 * 0.3Ω 0–50V OPA541 VIN R1 2.5kΩ –35V 0.5Ω 0.1µF VO A V = 1 + R 2 /R 1 = 5 * Protects DAC During Slewing 0.1µF –8V FIGURE 5. Paralleled Operation, Extended SOA. FIGURE 6. Programmable Voltage Source. +15V +35V 1µF 1µF 100pF Digital Word Input 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 MSB 18 23 OPA541 VOUT = –30V to +30V 1µF 21 DAC702 +15V ±1mA FB 10kΩ LSB 19 20 6 1µF 4 –15V 1µF –15V 5kΩ * 7 OPA27 2 3 17 1µF 10kΩ * –35V 0.5Ω * TCR Tracking Resistors FIGURE 7. 16-Bit Programmable Voltage Source. ® OPA541 8