POWER DUAL OPERATIONAL AMPLIFIERS PA21/25/26 • PA21A/25A M I C R O T E C H N O L O G Y HTTP://WWW.APEXMICROTECH.COM (800) 546-APEX (800) 546-2739 FEATURES • LOW COST • WIDE COMMON MODE RANGE — Includes negative supply • WIDE SUPPLY VOLTAGE RANGE Single supply: 5V to 40V Split supplies: ±2.5V to ±20V • HIGH EFFICIENCY — |Vs–2.2V| at 2.5A typ • HIGH OUTPUT CURRENT — 3A min (PA21A) • INTERNAL CURRENT LIMIT • LOW DISTORTION APPLICATIONS R1 • HALF & FULL BRIDGE MOTOR DRIVERS • AUDIO POWER AMPLIFIER STEREO — 18W RMS per channel BRIDGE — 36W RMS per package • IDEAL FOR SINGLE SUPPLY SYSTEMS 5V — Peripherals 12V — Automotive 28V — Avionic 5K R4 +28V 10K 10K – B + 1/2 PA21 – A M + 1/2 PA21 R5 10K R6 10K COMMAND INPUT 0/10V FIGURE 1: BIDIRECTIONAL SPEED CONTROL FROM A SINGLE SUPPLY The amplifiers are especially well-suited for this application. The extended common mode range allows command inputs as low as 0V. Its superior output swing abilities let it drive within 2V of supply at an output current of 2A. This means that a command input that ranges from 0V to 10V will drive a 24V motor from full scale CCW to full scale CW at up to ±2A. A single power op amp with an output swing capability of Vs –6 would require ±30V supplies and would be required to swing 48V p-p at twice the speed to deliver an equivalent drive. EXTERNAL CONNECTIONS PA26 OUT A 9 10 –IN, A 11 12 –IN B ISENSE/–VS 8 +VS 2 3 A OUT, A 1 4 – +IN, A + B + TOP VIEW –VS 6 PA25 7 VBOOST/+VS –IN A OUT, B 1 6 OUT B 5 ISENSE/–VS 4 –VS 3 + – +VS 2 A 5 OUT, A B SUB 1 +VS 2 +IN, A 3 –IN, A 4 + A – +IN B Connect pins 3 and 10 to pin 7 and connect pins 4 and 9 to pin 6 unless special functions are required. TYPICAL APPLICATION R1 and R2 set up amplifier A in a non-inverting gain of 2.8. Amp B is set up as a unity gain inverter driven from the output of amp A. Note that amp B inverts signals about the reference node, which is set at mid-supply (14V) by R5 and R6. When the command input is 5V, the output of amp A is 14V. Since this is equal to the reference node voltage, the output of amp B is also 14V, resulting in 0V across the motor. Inputs more positive than 5V result in motor current flow from left to right (see Figure 1). Inputs less positive than 5V drive the motor in the opposite direction. 9K +28V VBOOST/+VS The amplifiers consist of a monolithic dual power op amp in a 8-pin hermetic TO-3 package (PA21 and PA25) and a 12pin SIP package (PA26). Putting two power op amps in one package and on one die results in an extremely cost effective solution for applications requiring multiple amplifiers per board or bridge mode configurations. The wide common mode input range includes the negative rail, facilitating single supply applications. It is possible to have a “ground based” input driving a single supply amplifier with ground acting as the “second” or “bottom” supply of the amplifier. The output stages are also well protected. They possess internal current limit circuits. While the device is well protected, the Safe Operating Area (SOA) curve must be observed. Proper heatsinking is required for maximum reliability. This hybrid integrated circuit utilizes thick film (cermet) resistors, ceramic capacitors and semiconductor chips to maximize reliability, minimize size and give top performance. Ultrasonically bonded aluminum wires provide reliable interconnections at all operating temperatures. The 8-pin TO-3 package is hermetically sealed and electrically isolated. The use of compressible isolation washers voids the warranty. The tab of the SIP12 plastic package is tied to –VS. R3 +IN A DESCRIPTION R2 7 +IN, B B – 8 –IN, B 5 +IN, B –IN, B PA21 6 7 –VS 8 OUT, B APEX MICROTECHNOLOGY CORPORATION • TELEPHONE (520) 690-8600 • FAX (520) 888-3329 • ORDERS (520) 690-8601 • EMAIL [email protected] ABSOLUTE MAXIMUM RATINGS SPECIFICATIONS PA21/25/26 • PA21A/25A ABSOLUTE MAXIMUM RATINGS SUPPLY VOLTAGE, total OUTPUT CURRENT POWER DISSIPATION, internal (per amplifier) POWER DISSIPATION, internal (both amplifiers) INPUT VOLTAGE, differential INPUT VOLTAGE, common mode JUNCTION TEMPERATURE, max1 TEMPERATURE, pin solder—10 sec max TEMPERATURE RANGE, storage OPERATING TEMPERATURE RANGE, case SPECIFICATIONS PA21/25/26 TEST CONDITIONS 2 PARAMETER 5V to 40V SOA 25W 36W ±VS +VS, -VS–.5V 150°C 300°C –65°C to 150°C –55°C to 125°C MIN PA21A/PA25A TYP MAX 1.5 15 35 10 MIN TYP MAX UNITS .5 10 * 4 * * * mV µV/°C nA V dB dB dB * * * * dB kHz ° kHz INPUT OFFSET VOLTAGE, initial OFFSET VOLTAGE, vs. temperature BIAS CURRENT, initial COMMON MODE RANGE COMMON MODE REJECTION, DC POWER SUPPLY REJECTION CHANNEL SEPARATION Full temperature range Full temperature range Full temperature range Full temperature range IOUT = 1A, F = 1kHz –VS–.3 60 60 50 Full temperature range AV = 40dB Full temperature range VO(P-P) = 28V 80 1000 +VS–2 85 80 68 * * * * 250 * GAIN OPEN LOOP GAIN GAIN BANDWIDTH PRODUCT PHASE MARGIN POWER BANDWIDTH 100 600 65 13.6 * OUTPUT CURRENT, peak CURRENT, limit SLEW RATE CAPACITIVE LOAD DRIVE VOLTAGE SWING VOLTAGE SWING VOLTAGE SWING VOLTAGE SWING 2.5 AV = 1 Full temp. range, IO = 100mA Full temp. range, IO = 1A IO = 2.5A (PA21, 25) IO = 3.0A (PA21A, PA25A) 3 3.0 .5 1.2 .22 |VS| –1.0 |VS| –0.8 |VS| –1.8 |VS| –1.4 |VS| –3.0 |VS| –2.8 * * * A A V/µs µF V V V V 4.0 * * * * |VS| –4.0 |VS| –3.5 POWER SUPPLY 54 VOLTAGE, VSS3 CURRENT, quiescent, total 30 45 40 90 * * * * * V mA 85 °C/W °C/W °C/W °C/W °C/W °C THERMAL RESISTANCE, junction to case DC, single amplifier DC, both amplifiers5 AC, single amplifier AC, both amplifiers5 RESISTANCE, junction to air TEMPERATURE RANGE, case NOTES: * 1. 2. 3. 4. 5. CAUTION 5.0 3.4 3.7 2.4 30 Meets full range specifications –25 * * * 85 –25 The specification of PA21A/PA25A is identical to the specification for PA21/PA25 in applicable column to the left. Long term operation at the maximum junction temperature will result in reduced product life. Derate internal power dissipation to achieve high MTTF. Unless otherwise noted, the following conditions apply: ±VS = ±15V, TC = 25°C. +VS and –VS denote the positive and negative supply rail respectively. VSS denotes the total rail-to-rail supply voltage. Current limit may not function properly below VSS = 6V, however SOA violations are unlikely in this area. Rating applies when power dissipation is equal in the two amplifiers. The internal substrate contains beryllia (BeO). Do not break the seal. If accidentally broken, do not crush, machine, or subject to temperatures in excess of 850°C to avoid generating toxic fumes. (PA21 and PA25 only. PA26 does not contain BeO). APEX MICROTECHNOLOGY CORPORATION • 5980 NORTH SHANNON ROAD • TUCSON, ARIZONA 85741 • USA • APPLICATIONS HOTLINE: 1 (800) 546-2739 20 15 SINGLE AMPLIFIER 10 5 0 0 25 50 75 100 125 150 TEMPERATURE, T (°C) 1.5 75 1.25 1.0 .75 .5 SMALL SIGNAL RESPONSE PHASE, ϕ (°) 0 –150 10 100 1K 10K 100K 1M FREQUENCY, F (Hz) –210 0 POWER SUPPLY REJECTION 10 100 1K 10K .1M FREQUENCY, F (Hz) PULSE RESPONSE 89 OUTPUT VOLTAGE, VO (V) 83 80 77 74 71 5 0 –5 69 66 63 60 AV = 1 R L =10 Ω 10 86 –10 0 3 HARMONIC DISTORTION AV = –10 V OUT = 16VPP RL = 8Ω .1 .01 .001 10 0 10K 40K 100 1K FREQUENCY, F (Hz) 200 400 600 TIME, t (µs) 800 QUIESCENT CURRENT 1K 40 125 35 100 30 75 25 50 20 25 15 0 10 –25 CASE TEMPERATURE, TC (°C) 1 10 100 1K 10K 100K 1M FREQUENCY, F (Hz) 40 30 25 20 15 10 |+VS | + |–VS | = 40V 5 1K 1M NORMALIZED CURRENT LIMIT, I LIM (A) 1 POWER SUPPLY REJECTION, PSR (dB) –120 –180 –20 1K 10K 20K 100 FREQUENCY, F (Hz) POWER RESPONSE –90 TOTAL SUPPLY VOLTAGE, VSS (V) OPEN LOOP GAIN, A (dB) 20 AMP 2 I OUT = 0 AV = –100 60 50 –60 40 65 50 10 –30 60 70 PHASE RESPONSE 0 80 AMP 1 I OUT = 1A AV = –100 55 .25 –50 –25 0 25 50 75 100 125 CASE TEMPERATURE, TC (°C) 100 TOTAL HARMONIC DISTORTION, THD (%) CROSSTALK (dB) BOTH AMPLIFIERS 25 CROSSTALK 80 OUTPUT VOLTAGE, VO (VPP ) 35 30 BIAS CURRENT 1.75 5 –50 .9 1 1.1 1.2 1.3 1.4 .7 .8 NORMALIZED QUIESCENT CURRENT, I Q (X) VOLTAGE DROP FROM SUPPLY, (V) POWER DERATING 40 PA21/25/26 • PA21A/25A NORMALIZED BIAS CURRENT, I B (X) INTERNAL POWER DISSIPATION, P(W) TYPICAL PERFORMANCE GRAPHS 10K FREQUENCY, F (Hz) 100K CURRENT LIMIT 1.6 1.4 1.2 1.0 .8 .6 .4 –50 –25 0 25 50 75 100 125 CASE TEMPERATURE, TC (°C) OUTPUT VOLTAGE SWING 3.5 3 2.5 2 1.5 1 .5 0 0 .5 1 1.5 2 2.5 3 OUTPUT CURRENT, I O (A) 3.5 APEX MICROTECHNOLOGY CORPORATION • TELEPHONE (520) 690-8600 • FAX (520) 888-3329 • ORDERS (520) 690-8601 • EMAIL [email protected] OPERATING CONSIDERATIONS PA21/25/26 • PA21A/25A GENERAL Please read Application Note 1 "General Operating Considerations" which covers stability, supplies, heat sinking, mounting, current limit, SOA interpretation, and specification interpretation. Visit www.apexmicrotech.com for design tools that help automate tasks such as calculations for stability, internal power dissipation, current limit and heat sink selection. The "Application Notes" and "Technical Seminar" sections contain a wealth of information on specific types of applications. Package outlines, heat sinks, mounting hardware and other accessories are located in the "Packages and Accessories" section. Evaluation Kits are available for most Apex product models, consult the "Evaluation Kit" section for details. For the most current version of all Apex product data sheets, visit www.apexmicrotech.com. EA CH ,O NE CH ,B OT H 1 s EA m 2 1 OUTPUT CURRENT FROM +V S OR –VS (A) 4 3 LO AD LO ED AD ED * If the inductive load is driven near steady state conditions, allowing the output voltage to drop more than 6V below the supply rail while the amplifier is current limiting, the inductor should be capacitively coupled or the supply voltage must be lowered to meet SOA criteria. NOTE: For protection against sustained, high energy flyback, external fast-recovery diodes should be used. MONOLITHIC AMPLIFIER STABILITY CONSIDERATIONS All monolithic power op amps use output stage topologies that present special stability problems. This is primarily due to non-complementary (both devices are NPN) output stages with a mismatch in gain and phase response for different polarities of output current. It is difficult for the op amp manufacturer to optimize compensation for all operating conditions. The recommended R-C network of 1 ohm in series with 0.1µF from output to AC common (ground or a supply rail, with adequate bypass capacitors) will prevent local output stage oscillations. This network is provided internally on the PA21 but must be supplied externally on the PA25 and PA26. The amplifiers are internally compensated for unity gain stability, no additional compensation is required. THERMAL CONSIDERATIONS T C = 25°C .1 1 2 3 4 5 6 10 20 30 40 50 SUPPLY TO OUTPUT DIFFERENTIAL VOLTAGE V S –VO (V) CURRENT LIMIT Current limit is internal to the amplifier, the typical value is shown in the current limit specification. Although R θJC is the same for PA21/25/26 there are differences in the thermal interface between case and heatsink which will limit power dissipation capability. Thermal grease or an Apex TW03 thermal washer, R θCS = .1-.2°C/W, is the only recommended interface for the PA21/25. The PA26 may require a thermal washer which is electrically insulating since the tab is tied to –VS. This can result in thermal impedances for R θCS of up to 1°C/W or greater. VBOOST SAFE OPERATING AREA (SOA) The SOA curves combine the effect of all limits for this power op amp. For a given application, the direction and magnitude of the output current should be calculated or measured and checked against the SOA curves. This is simple for resistive loads but more complex for reactive and EMF generating loads. The following guidelines may save extensive analytical efforts. Under transient conditions, capacitive and dynamic* inductive loads up to the following maximum are safe: ±Vs 20V 15V 10V 5V +VS – IN +IN OUT ISENSE RS CAPACITIVE LOAD INDUCTIVE LOAD 200µF 500µF 5mF 50mF 7.5mH 25mH 35mH 150mH – VS FIGURE 2. PA26 EQUIVALENT SCHEMATIC (ONE CHANNEL) APEX MICROTECHNOLOGY CORPORATION • 5980 NORTH SHANNON ROAD • TUCSON, ARIZONA 85741 • USA • APPLICATIONS HOTLINE: 1 (800) 546-2739 OPERATING CONSIDERATIONS PA21/25/26 • PA21A/25A ADDITIONAL PA26 PIN FUNCTIONS +VS VBOOST PA26 The VBOOST pin is the positive terminal for the load of the second stage of the amplifier. When that terminal is connected to a voltage greater than +VS it will provide more drive to the upper output transistor, which is a darlington connected emitter follower. This will better saturate the output transistor. When VBOOST is about 5 Volts greater than +VS the positive output can swing 0.5 Volts closer to the rail. This is as much improvement as is possible. VBOOST pin requires approximately 10–12mA of current. Dynamically it represents 1K Ω impedance. The maximum voltage that can be applied to VBOOST is 40 volts with respect to –VS . There is no limit to the difference between +VS and VBOOST. VBIAS B R RL VIN IL R A RFB RIN RS RS RIN RFB +VS ≤ 20V DB1 7 DB2 3 –VS OR GND 10 FIGURE 4. ISENSE TRANSCONDUCTANCE BRIDGING AMPLIFIER CB1 PA26A 5 CB2 PA26B VREF SPEAKER 8 FIGURE 3. SIMPLE BOOTSTRAPPING IMPROVES POSITIVE OUTPUT SWING. CONNECT PINS 3 AND 10 TO VS IF NOT USED. TYPICAL CURRENTS ARE 12mA EACH. Figure 3 shows a bootstrap which dynamically couples the output waveform onto the VBOOST pin. This causes VBOOST to swing positive from it's initial value, which is equal to +VS -0.7 V (one diode drop), an amount equal to the output. In other words, if VBOOST was initially 19.3, and the output swings positive 18 Volts, the voltage on the VBOOST pin will swing to 19.3 -0.7 + 18 or 36.6. The capacitor needs to be sized based on a 1K Ω impedance and the lowest frequency required by the circuit. For example, 20Hz will require > 8uF. ISENSE The ISENSE pin is in series with the negative half of the output stage only. Current will flow through this pin only when negative current is being outputted. The current that flows in this pin is the same current that flows in the output (if –1A flows in the output, the ISENSE pin will have 1A of current flow, if +1A flows in the output the ISENSE pin will have 0 current flow). The resistor choice is arbitrary and is selected to provide whatever voltage drop the engineer desires, up to a maximum of 1.0 volt. However, any voltage dropped across the resistor will subract from the swing to rail. For instance, assume a +/– 12 volt power supply and a load that requires +/–1A. With no current sense resistor the output could swing +/–10.2 volts. If a 1 Ω resistor is used for current sense (which will drop 1 Volt at 1 Amp) then the output could swing +10.2, –9.2 Volts. Figure 4 shows the PA26 ISENSE feature being used to obtain a Transconductance function. In this example, amplifier "A" is the master and amplifier "B" is the slave. Feedback from sensing resistors RS is applied to the summing network and scaled to the inverting input of amplifier "A" where it is compared to the input voltage. The current sensing feedback imparts a Transconductance feature to the amplifiers transfer function. In other words, the voltage developed across the sensing resistors is directly proportional to the output current. Using this voltage as a feedback source allows expressing the gain of the circuit in amperes vs input voltage. The transfer funcion is approximately: IL= (VIN – VREF) *RIN/ RFB/ Rs In the illustration, resistors RIN, RFB and RS determine gain. VBIAS should be set midway between +Vs and -Vs, Vref is usually ground in dual supply systems or used for level translation in single supply systems. MOUNTING PRECAUTIONS 1. Always use a heat sink. Even unloaded, the PA26 can dissipate up to 3.6 watts. A thermal washer or thermal grease should always be used. 2. Avoid bending the leads. Such action can lead to internal damage. 3. Always fasten the tab to the heat sink before the leads are soldered to fixed terminals. 4. Strain relief must be provided if there is any probability of axial stress to the leads. This data sheet has been carefully checked and is believed to be reliable,(520) however, no responsibility assumed888-3329 for possible •inaccuracies or omissions. All specifications subject to change without notice. APEX MICROTECHNOLOGY CORPORATION • TELEPHONE 690-8600 • FAXis(520) ORDERS (520) 690-8601 • EMAILare [email protected] PA21/25/26U REV. G FEBRUARY 2000 © 2000 Apex Microtechnology Corp.