LH0101 Power Operational Amplifier General Description Features The LH0101 is a wideband power operational amplifier featuring FET inputs, internal compensation, virtually no crossover distortion, and rapid settling time. These features make the LH0101 an ideal choice for DC or AC servo amplifiers, deflection yoke drives, programmable power supplies, and disk head positioner amplifiers. The LH0101 is packaged in an 8 pin TO-3 hermetic package, rated at 60 watts with a suitable heat sink. Y Y Y Y Y Y Y Y 5 Amp peak, 2 Amp continuous output current 300 kHz power bandwidth 850 mW standby power ( g 15V supplies) 300 pA input bias current 10 V/ms slew rate Virtually no crossover distortion 2 ms settling time to 0.01% 5 MHz gain bandwidth Schematic and Connection Diagrams TL/K/5558 – 2 Top View Order Numbers LH0101K, LH0101K-MIL, LH0101CK, LH0101AK, LH0101AK-MIL or LH0101ACK See NS Package Number K08A Note: Electrically connected internally, no connection should be made to pin. TL/K/5558 – 1 C1995 National Semiconductor Corporation TL/K/5558 RRD-B30M115/Printed in U. S. A. LH0101 Power Operational Amplifier February 1995 Absolute Maximum Ratings Peak Output Current (50 ms pulse), IO(PK) If Military/Aerospace specified devices are required, please contact the National Semiconductor Sales Office/Distributors for availability and specifications. (Note 5) g 22V Supply Voltage, VS Power Dissipation at TA e 25§ C, PD Derate linearly at 25§ C/W to zero at 150§ C, Power Dissipation at TC e 25§ C Derate linearly at 2§ C/W to zero at 150§ C g 40V but k Differential Input Voltage, VIN g 20V but k Input Voltage Range, VCM Thermal ResistanceÐ See Typical Performance Characteristics Output Short Circuit Duration (within rated power dissipation, RSC e 0.35X, TA e 25§ C) Operating Temperature Range, TA LH0101AC, LH0101C LH0101A, LH0101 5W 62W 5A Continuous b 25§ C to a 85§ C b 55§ C to a 125§ C b 65§ C to a 150§ C Storage Temperature Range, TSTG Maximum Junction Temperature, TJ 150§ C 260§ C Lead Temperature (Soldering k10 sec.) ESD rating to be determined. g VS g VS DC Electrical Characteristics (Note 1) VS e g 15V, TA e 25§ C unless otherwise noted Symbol Parameter LH0101AC LH0101A Conditions Min VOS Input Offset Voltage Typ Max 1 TMIN s TA s TMAX IB Change in Input Offset Voltage with Temperature 3 Units Typ Max 5 10 mV 15 150 300 mV/W 10 10 mV/§ C VCM e 0 Input Bias Current TA s TMAX IOS Min 7 DVOS/DPD Change in (Note 2) Input Offset Voltage with Dissipated Power DVOS/DT LH0101C LH0101 300 1000 LH0101C/AC 60 60 LH0101/A 300 1000 75 250 LH0101C/AC 15 15 LH0101/A 75 250 Input Offset Current TA s TMAX AVOL Large Signal Voltage Gain VO e g 10V RL e 10X VO Output Voltage Swing RSC e 0 RL e 100X AV e a 1 RL e 10X Note 3 RL e 5X 50 200 g 12 g 12.5 g 11.25 g 11.6 50 200 g 12 g 12.5 g 11 g 10.5 g 11 CMRR Common Mode Rejection Ratio DVIN e g 10V 85 100 85 100 PSRR Power Supply Rejection Ratio DVS e g 5V to g 15V 85 100 85 100 IS Quiescent Supply Current nA pA nA V/mV g 11.25 g 11.6 g 10.5 pA V dB 28 2 35 28 35 mA AC Electrical Characteristics (Note 1), VS e g 15V, TA e 25§ C Symbol Parameter LH0101 LH0101A Conditions Min en Equivalent Input Noise Voltage f e 1 kHz CIN Input Capacitance f e 1 MHz Power Bandwidth, b3 dB SR Slew Rate tr, tf Small Signal Rise or Fall Time 7.5 (Note 4) RL e 10X AV e a 1 Small Signal Overshoot GBW Gain-Bandwidth Product ts Large Signal Settling Time to 0.01% THD Total Harmonic Distortion 4.0 (Note 4) RL e % Po e 10W, f e 1 kHz RL e 10X Typ LH0101C LH0101AC Max Min Typ Units Max 25 25 nV0Hz 3.0 3.0 pF 300 300 kHz 10 10 V/ms 200 200 ns 10 10 % 5.0 5.0 MHz 2.0 2.0 ms 0.008 0.008 % Note 1: Specification is at TA e 25§ C. Actual values at operating temperature may differ from the TA e 25§ C value. When supply voltages are g 15V, quiescent operating junction temperature will rise approximately 20§ C without heat sinking. Accordingly, VOS may change 0.5 mV and IB and IOS will change significantly during warm-ups. Refer to the IB vs. temperature and power dissipation graphs for expected values. Power supply voltage is g 15V. Temperature tests are made only at extremes. Note 2: Change in offset voltage with dissipated power is due entirely to average device temperature rise and not to differential thermal feedback effects. Test is performed without any heat sink. Note 3: At light loads, the output swing may be limited by the second stage rather than the output stage. See the application section under ‘‘Output swing enhancement’’ for hints on how to obtain extended operation. Note 4: These parameters are sample tested to 10% LTPD. Note 5: Refer to RETS0101AK for the LH0101AK military specifications and RETS0101K for the LH0101K military specifications. 3 Typical Performance Characteristics Maximum Power Dissipation Safe Operating Area Quiescent Power Supply Current Input Bias Current Input Bias Current after Warm-up Input Common-Mode Voltage Range Small Signal Frequency Response (open loop) Output Voltage Swing vs. Frequency Common-Mode Rejection Ratio vs. Frequency Power Supply Rejection Ratio vs. Frequency Settling Time Total Harmonic Distortion vs. Frequency TL/K/5558 – 3 4 Typical Performance Characteristics (Continued) Total Harmonic Distortion vs. Gain Equivalent Input Noise Voltage Output Voltage Swing with Swing Enhancement Output Voltage Swing vs. Load Resistance Open-Loop Output Resistance Open-Loop Output Resistance vs. Frequency Short Circuit Current vs. RSC TL/K/5558 – 4 Small Signal Pulse Response (No Load) Large Signal Pulse Response (RL e 10X) TL/K/5558 – 5 TL/K/5558 – 6 5 Application Hints Electrostatic shielding of high impedance circuitry is advisable. Input Voltages The LH0101 operational amplifier contains JFET input devices which exhibit high reverse breakdown voltages from gate to source or drain. This eliminates the need for input clamp diodes, so that high differential input voltages may be applied without a large increase in input current. However, neither input voltage should be allowed to exceed the negative supply as the resultant high current flow may destroy the unit. Exceeding the negative common-mode limit on either input will cause a reversal of the phase to the output and force the amplifier output to the corresponding high or low state. Exceeding the negative common-mode limit on both inputs will force the amplifier output to a high state. In neither case does a latch occur since raising the input back within the common-mode range again puts the input stage and thus the amplifier in a normal operating mode. Exceeding the positive common-mode limit on a single input will not change the phase of the output however, if both inputs exceed the limit, the output of the amplifier will be forced to a high state. These amplifiers will operate with the common-mode input voltage equal to the positive supply. In fact, the commonmode voltage may exceed the positive supply by approximately 100 mV, independent of supply voltage and over the full operating temperature range. The positive supply may therefore be used as a reference on an input as, for example, in a supply current monitor and/or limiter. With the LH0101 there is a temptation to remove the bias current compensation resistor normally used on the non-inverting input of a summing amplifier. Direct connection of the inputs to ground or a low-impedance voltage source is not recommended with supply voltages greater than 3V. The potential problem involves loss of one supply which can cause excessive current in the second supply. Destruction of the IC could result if the current to the inputs of the device is not limited to less than 100 mA or if there is much more than 1 mF bypass on the supply buss. Although difficulties can be largely avoided by installing clamp diodes across the supply lines on every PC board, a conservative design would include enough resistance in the input lead to limit current to 10 mA if the input lead is pulled to either supply by internal currents. This precaution is by no means limited to the LH0101. Error voltages can also be generated in the external circuitry. Thermocouples formed between dissimilar metals can cause hundreds of microvolts of error in the presence of temperature gradients. Since the LH0101 can deliver large output currents, careful attention should be paid to power supply, power supply bypassing and load currents. Incorrect grounding of signal inputs and load can cause significant errors. Every attempt should be made to achieve a single point ground system as shown in the figure below. TL/K/5558 – 7 FIGURE 1. Single-Point Grounding Bypass capacitor CBX should be used if the lead lengths of bypass capacitors CB are long. If a single point ground system is not possible, keep signal, load, and power supply from intermingling as much as possible. For further information on proper grounding techniques refer to ‘‘Grounding and Shielding Techniques in Instrumentation’’ by Morrison, and ‘‘Noise Reduction Techniques in Electronic Systems’’ by Ott (both published by John Wiley and Sons). Leads or PC board traces to the supply pins, short-circuit current limit pins, and the output pin must be substantial enough to handle the high currents that the LH0101 is capable of producing. Layout Considerations When working with circuitry capable of resolving pico-ampere level signals, leakage currents in circuitry external to the op amp can significantly degrade performance. High quality insulation is a must (Kel-F and Teflon rate high). Proper cleaning of all insulating surfaces to remove fluxes and other residues is also required. This includes the IC package as well as sockets and printed circuit boards. When operating in high humidity environments or near 0§ C, some form of surface coating may be necessary to provide a moisture barrier. The effects of board leakage can be minimized by encircling the input circuitry with a conductive guard ring operated at a potential close to that of the inputs. Short Circuit Current Limiting Should current limiting of the output not be necessary, SC a should be shorted to V a and SCb should be shorted to Vb. Remember that the short circuit current limit is dependent upon the total resistance seen between the supply and current limit pins. This total resistance includes the desired resistor plus leads, PC Board traces, and solder joints.* Assuming a zero TCR current limit resistor, typical temperature coefficient of the short circuit current will be approximately .3%/§ C. *Short circuit current will be limited to approximately 6 0.6 . RSC Application Hints (Continued) ground set the frequency of the pole. In many instances the frequency of this pole is much greater than the expected 3 dB frequency of the closed loop gain and consequently there is negligible effect on stability margin. However, if the feedback pole is less than approximately six times the expected 3 dB frequency a lead capacitor should be placed from the output to the input of the op amp. The value of the added capacitor should be such that the RC time consistant of this capacitor and the resistance it parallels is greater than or equal to the original feedback pole time constant. Some inductive loads may cause output stage oscillation. A .01 mF ceramic capacitor in series with a 10X resistor from the output to ground will usually remedy this situation. Thermal Resistance The thermal resistance between two points of a conductive system is expressed as: T1 b T2 i12 e § C/W PD where subscript order indicates the direction of heat flow. A simplified heat transfer circuit for a cased semiconductor and heat sink system is shown in the figure below. The circuit is valid only if the system is in thermal equilibrium (constant heat flow) and there are, indeed, single specific temperatures TJ, TC and TS (no temperature distribution in junction, case, or heat sink). Nevertheless, this is a reasonable approximation of actual performance. TL/K/5558 – 8 TL/K/5558 – 9 FIGURE 2. Semiconductor-Heat Sink Thermal Circuit The junction-to-case thermal resistance iJC specified in the data sheet depends upon the material and size of the package, die size and thickness, and quality of the die bond to the case or lead frame. The case-to-heat sink thermal resistance iCS depends on the mounting of the device to the heat sink and upon the area and quality of the contact surface. Typical iCS for a TO-3 package is 0.5 to 0.7§ C/W, and 0.3 to 0.5§ C/W using silicone grease. The heat sink to ambient thermal resistance iSA depends on the quality of the heat sink and the ambient conditions. Cooling is normally required to maintain the worst case operating junction temperature TJ of the device below the specified maximum value TJ(MAX). TJ can be calculated from known operating conditions. Rewriting the above equation, we find: FIGURE 3. Driving Inductive Loads Capacitive loads may be compensated for by traditional techniques. (See ‘‘Operational Amplifiers: Theory and Practice’’ by Roberge, published by Wiley): TJ b TA iJA e § C/W PD TJ e TA a PDiJA § C Where: PD (VS b VOUT)IOUT a lV a b (Vb)lIQ for a DC Signal TL/K/5558 – 10 FIGURE 4. RC and CC Selected to Compensate for Capacitive Load A similar but alternative technique may be used for the LH0101: iJA e iJC a iCS a iSA and VS e Supply Voltage iJC for the LH0101 is about 2§ C/W. Stability and Compensation As with most amplifiers, care should be taken with lead dress, component placement and supply decoupling in order to ensure stability. For example, resistors from the output to an input should be placed with the body close to the input to minimize ‘‘pickup’’ and maximize the frequency of the feedback pole by minimizing the capacitance from the input to ground. A feedback pole is created when the feedback around any amplifier is resistive. The parallel resistance and capacitance from the input device (usually the inverting input) to ac TL/K/5558 – 11 FIGURE 5. Alternate Compensation for Capacitive Load 7 Application Hints (Continued) Output Resistance Output Swing Enhancement When the feedback pin is connected directly to the output, the output voltage swing is limited by the driver stage and not by output saturation. Output swing can be increased as shown by taking gain in the output stage as shown in High Power Voltage Follower with Swing Enhancement below. Whenever gain is taken in the output stage, as in swing enhancement, either the output stage, or the entire op amp must be appropriately compensated to account for the additional loop gain. The open loop output resistance of the LH0101 is a function of the load current. No load output resistance is approximately 10X. This decreases to under 1X for load currents exceeding 100 mA. Typical Applications See AN261 for more information. TL/K/5558–12 TL/K/5558 – 13 FIGURE 6. High Power Voltage Follower FIGURE 7. High Power Voltage Follower with Swing Enhancement TL/K/5558 – 14 FIGURE 8. Restricting Outputs to Positive Voltages Only Following is a partial list of sockets and heat dissipators for use with the LH0101. National assumes no responsibility for their quality or availability. 8-Lead TO-3 Hardware SOCKETS Keystone 4626 or 4627 Keystone Electronics Corp. AAVID Engineering Robinson Nugent 0002011 49 Bleecker St. 30 Cook Court Azimuth 6028 (test socket) New York, NY 10012 Laconla, New Hampshire 03246 HEAT SINKS Robinson Nugent Inc. Azimuth Electronics Thermalloy 2266B (35§ C/W) 800 E. 8th St. 2377 S. El Camino Real IERC LAIC3B4CB New Albany, IN 47150 San Clemente, CA 92572 IERC HP1-TO3-33CB (7§ C/W) Thermalloy IERC AAVID 5791B P.O. Box 34829 135 W. Magnolia Blvd. MICA WASHERS Dallas, TX 75234 Burbank, CA 91502 Keystone 4658 8 Typical Applications (Continued) TL/K/5558 – 15 FIGURE 9. Generating a Split Supply from a Single Voltage Supply TL/K/5558 – 16 FIGURE 10. Power DAC TL/K/5558 – 17 FIGURE 11. Bridge Audio Amplifier 9 Typical Applications (Continued) TL/K/5558 – 18 FIGURE 12. g 5 to g 35 Power Source or Sink TL/K/5558 – 19 FIGURE 13. Remote Loudspeaker via Infrared Link TL/K/5558 – 20 FIGURE 14. CRT Deflection Yoke Driver 10 Typical Applications (Continued) TL/K/5558 – 21 FIGURE 15. DC Servo Amplifier TL/K/5558 – 22 FIGURE 16. High Current Source/Sink 11 LH0101 Power Operational Amplifier Physical Dimensions inches (millimeters) Lit. Ý 106400 8 Lead TO-3 Metal Can (K) Order Number LH0101K, LH0101K-MIL, LH0101CK, LH0101AK, LH0101AK-MIL or LH0101ACK NS Package Number K08A LIFE SUPPORT POLICY NATIONAL’S PRODUCTS ARE NOT AUTHORIZED FOR USE AS CRITICAL COMPONENTS IN LIFE SUPPORT DEVICES OR SYSTEMS WITHOUT THE EXPRESS WRITTEN APPROVAL OF THE PRESIDENT OF NATIONAL SEMICONDUCTOR CORPORATION. As used herein: 1. Life support devices or systems are devices or systems which, (a) are intended for surgical implant into the body, or (b) support or sustain life, and whose failure to perform, when properly used in accordance with instructions for use provided in the labeling, can be reasonably expected to result in a significant injury to the user. National Semiconductor Corporation 1111 West Bardin Road Arlington, TX 76017 Tel: 1(800) 272-9959 Fax: 1(800) 737-7018 2. A critical component is any component of a life support device or system whose failure to perform can be reasonably expected to cause the failure of the life support device or system, or to affect its safety or effectiveness. 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