High Power Monolithic OPERATIONAL AMPLIFIER

Transcription

1 High Power Monolithic OPERATIONAL AMPLIFIER FEATURES POWER SUPPLIES TO ±0V OUTPUT CURRENT TO 0A PEAK PROGRAMMABLE CURRENT LIMIT INDUSTRY-STANDARD PIN OUT FET INPUT TO- AND LOW-COST POWER PLASTIC PACKAGES DESCRIPTION The is a power operational amplifier capable of operation from power supplies up to ±0V 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 is fabricated using a proprietary bipolar/fet process. Pinout is compatible with popular hybrid power amplifiers such as the OPA5, OPA5 and the 57. APPLICATIONS MOTOR DRIVER SERVO AMPLIFIER SYNCHRO EXCITATION AUDIO AMPLIFIER PROGRAMMABLE POWER SUPPLY The 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 is available in an -pin power plastic package and an industry-standard -pin TO- hermetic package. The power plastic package has a copper-lead frame to maximize heat transfer. The TO- package is isolated from all circuitry, allowing it to be mounted directly to a heat sink without special insulators. +V S In +In Current Sense V O Output Drive External V S International Airport Industrial Park Mailing Address: PO Box 00 Tucson, AZ 57 Street Address: 70 S. Tucson Blvd. Tucson, AZ 570 Tel: (50) 7- Twx: Cable: BBRCORP Telex: 0-9 FAX: (50) 9-50 Immediate Product Info: (00) 5-97 Burr-Brown Corporation PDS-77G Printed in U.S.A. October, 99

2 SPECIFICATIONS ELECTRICAL At T C = +5 C and V S = ±5VDC unless otherwise noted. AM/AP BM/SM PARAMETER CONDITIONS MIN TYP MAX MIN TYP MAX UNITS INPUT OFFSET VOLTAGE V OS ± ±0 ±0. ± mv vs Temperature Specified Temperature Range ±0 ±0 ±5 ±0 µv/ C vs Supply Voltage V S = ±0V to ±V MAX ±.5 ±0 * * µv/v vs Power ±0 ±0 * * µv/w INPUT BIAS CURRENT I B 50 * * pa INPUT OFFSET CURRENT I OS ± ±0 * * pa Specified Temperature Range 5 * na INPUT CHARACTERISTICS Common-Mode Voltage Range Specified Temperature Range ±( V S ) ±( V S ) * * V Common-Mode Rejection V CM = ( ±V S V) 95 * * db Input Capacitance 5 * pf Input Impedance, DC * TΩ GAIN CHARACTERISTICS Open Loop Gain at 0Hz R L = Ω * * db Gain-Bandwidth Product. * MHz OUTPUT Voltage Swing I O = 5A, Continuous ±( V S 5.5) ±( V S.5) * * V I O = A ±( V S.5) ±( V S.) * * V I O = 0.5A ±( V S ) ±( V S.) * * V Current, Peak 9 0 * * A AC PERFORMANCE Slew Rate 0 * * V/µs Power Bandwidth R L = Ω, V O = 0Vrms 5 55 * * khz Settling Time to 0.% V Step * µs Capacitive Load Specified Temperature Range, G =. * nf Specified Temperature Range, G >0 SOA () * Phase Margin Specified Temperature Range, R L = Ω 0 * Degrees POWER SUPPLY Power Supply Voltage, ±V S Specified Temperature Range ±0 ±0 ±5 * ±5 ±0 V Current, Quiescent 0 5 * * ma THERMAL RESISTANCE θ JC (Junction-to-Case) () AC Output f > 0Hz.5 C/W θ () JC DC Output C/W θ JA (Junction-to-Ambient) No Heat Sink 0 C/W AP (Plastic) 0 C/W TEMPERATURE RANGE T CASE AM, BM, AP 5 +5 * * C SM C * Specification same as AM/AP. NOTE: () SOA is the Safe Operating Area shown in Figure. () Plastic package may require insulator which typically adds 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.

3 DICE INFORMATION PAD FUNCTION NC V S V S V S 5 V S NC 7 In +In 9 NC 0 NC PAD FUNCTION NC Current Sense +V S +V S 5 +V S +V S 7 Current Sense Output Drive 9 Output Drive 0 Output Drive Output Drive NOTE: For full output current capability, wire-bond all like connections of +V S, V S and Output Drive. Substrate Bias: Electrically connected to V S supply. MECHANICAL INFORMATION MILS (0.00") MILLIMETERS Die Size x 05 ±5 5. x 5. ±0. Die Thickness 0 ± 0.5 ±0.0 Min. Pad Size x 0. x 0. Backing Chromium-Silver DIE TOPOGRAPHY CONNECTION DIAGRAMS Top View TO Top View Plastic Package +In +V NC S Current Sense Tab at V S In 5 V S 7 NC Output Drive ABSOLUTE MAXIMUM RATINGS Supply Voltage, +V S to V S... 0V Output Current... see SOA Power Dissipation, Internal ()... 5W Input Voltage: Differential... ±V S Common-mode... ±V S Temperature: Pin solder, 0s C Junction () C Temperature Range: AM, BM SM Storage... 5 C to +50 C Operating (case) C to +5 C AP Storage... 0 C to +5 C Operating (case)... 5 C to +5 C NOTE: () Long term operation at the maximum junction temperature will result in reduced product life. Derate internal power dissipation to achieve high MTTF. VO 0 In 5 NC 7 9 +In Output Drive NC Current V Sense S +V S V O ORDERING INFORMATION TEMPERATURE CONTINUOUS MODEL PACKAGE RANGE CURRENT AP Power Plastic 5 C to +5 C 5A at 5 C AM TO- 5 C to +5 C 5A at 5 C BM TO- 5 C to +5 C 5A at 5 C SM TO- 55 C to +5 C 5A at 5 C PACKAGE INFORMATION PACKAGE DRAWING MODEL PACKAGE NUMBER () AP Power Plastic AM TO- 00 BM TO- 00 SM TO- 00 NOTE: () For detailed drawing and dimension table, please see end of data sheet, or Appendix D of Burr-Brown IC Data Book.

4 TYPICAL PERFORMANCE CURVES T A = +5 C, V S = ±5VDC unless otherwise noted. 00 INPUT BIAS CURRENT vs TEMPERATURE 0 OPEN-LOOP GAIN AND PHASE vs FREQUENCY Input Bias Current (na) Temperature ( C) Voltage Gain (db) Phase Gain Z =.nf L Z =.nf L Z L = kω Z L = kω 0 00 k 0k 00k M 0M Frequency (Hz) Phase (Degrees). NORMALIZED QUIESCENT CURRENT vs TOTAL POWER SUPPLY VOLTAGE OUTPUT VOLTAGE SWING vs OUTPUT CURRENT Normalized I Q T = 5 C C T = +5 C C T = +5 C C ±V S V OUT (V) 5 (+V S) VO V S V O V S + V S (V) I OUT (A) k VOLTAGE NOISE DENSITY vs FREQUENCY 0 TOTAL HARMONIC DISTORTION + NOISE vs FREQUENCY Voltage Noise Density (nv/ Hz) 00 THD + Noise (%) P = 00mW O P = 5W O P = 50W O A = 5 V k 0k 00k Frequency (Hz) k 0k 00k Frequency (Hz)

5 TYPICAL PERFORMANCE CURVES (CONT) T A = +5 C, V S = ±5VDC unless otherwise noted. 0 TO- CURRENT LIMIT vs RESISTANCE LIMIT Power Plastic 0 CURRENT LIMIT vs RESISTANCE LIMIT vs TEMPERATURE TO- at 5 C TO- at +5 C Power Plastic at 5 C Power Plastic at +5 C I LIMIT (A) I LIMIT (A) NOTE: These are averaged values. I OUT is typically 0% higher. +I OUT is typically 0% lower ( Ω) NOTE: These are averaged values. I OUT is typically 0% higher. +I OUT is typically 0% lower ( Ω) 0 0 COMMON-MODE REJECTION vs FREQUENCY DYNAMIC RESPONSE CMRR (db) Voltage (V/division) k 0k 00k M Frequency (Hz) Time (µs/division) 5

6 INSTALLATION INSTRUCTIONS POWER SUPPLIES The is specified for operation from power supplies up to ±0V. 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 0V. 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,. 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: 0.09 (AM, BM, SM) = I LIM 0. (AP) = 0.0 I LIM Because of the internal structure of the, the actual current limit depends on whether current is positive or negative. The above gives an average value. For a given, +I OUT will actually be limited at about 0% below the expected level, while I OUT will be limited about 0% 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 at other temperatures may be calculated by adjusting as follows: mv = x (T 5) I LIM 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, it must be selected for sufficient power dissipation. For a 5A current limit on the TO- package, the formula yields an of 0.05Ω (0.Ω on the power plastic package due to different internal resistances). A continuous 5A through 0.05Ω would require an that can dissipate.5w. Sinusoidal outputs create dissipation according to rms load current. For the same, AC peaks would still be limited to 5A, but rms current would be.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. 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 = T CASE T AMBIENT P D (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- package. Since mica and other similar insulators typically add approximately 0.7 C/W thermal resistance, their elimination significantly improves thermal performance. See Burr- Brown Application Note AN- for further details on heat sinking. On the power plastic package, the metal tab is connected to V S, 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. It shows the allowable output current as a function of the voltage across the conducting output transistor (see Figure ). 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.

7 0 SAFE OPERATING AREA APPLICATIONS CIRCUITS T C = +5 C T C = +5 C +V S 0µF I O (A) T C = +5 C M Package only 0.µF D AP, AM BM, SM V S V OUT (V) 0µF 0.µF D L Inductive or EMF-Generating Load D D : IN00 FIGURE. Safe Operating Area. V S 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 V S ±5V, a short to ground would force 5V across the conducting power transistor. A current limit of.a 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 Note AN- for further information on evaluating SOA. REPLACING HYBRID POWER AMPLIFIERS The can be used in applications currently using various hybrid power amplifiers, including the OPA50, OPA5, OPA5, and 57. Of course, the application must be evaluated to assure that the output capability and other performance attributes of the 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 uses only one current limit resistor to set both the positive and negative current limit, only one resistor (see Figure ) need be installed. If installed, the resistor connected to pin (TO- 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. Clamping Output for EMF-Generating Loads. V IN R 0kΩ R 00kΩ 0.Ω FIGURE. Isolating Capacitive Loads. OPA50 + 0pF Master Slave 0kΩ 0pF 0. Ω FIGURE. Replacing OPA50 with. Not Required A V= R /R = 0 Pin is open on. L 7

8 0.µF +5V 0.µF +0V R 0kΩ 5kΩ V IN R.5kΩ 0pF 0.µF 5V 0.5 Ω V O A = + R /R = 5 V DAC0-CBI-I * Protects DAC During Slewing 0 ma * 0.Ω 0.µF V V O 0 50V FIGURE 5. Paralleled Operation, Extended SOA. FIGURE. Programmable Voltage Source. +5V +5V µf µf Digital Word Input MSB LSB µf DAC70 9 ±ma 0 FB 0kΩ 7 00pF µf 5V +5V µf 7 OPA7 0.5Ω V OUT = 0V to +0V 0kΩ* * TCR Tracking Resistors 5V µf 5kΩ * 5V FIGURE 7. -Bit Programmable Voltage Source.

9 PACKAGE DRAWINGS 9