apex microtechnology corporation telephone (520) 690-8600 fax (520) 888-3329 orders (520) 690-8601 email prodlit@apexmi crotech.com c 1 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 ? 2.5a min internal current limit low distortion applications 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 description the PA34 consist of a monolithic power op amp in a 7-pin t0220 package. 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 ampli? er with ground acting as the ?second? or ?bottom? supply of the ampli? er. the output stage is 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. the tab of the 7 pin plastic package is tied to ?v s . graphic for PA34 here http://www.apexmicrotech.com (800) 546-apex (800) 546-2739 microtechnology power operational amplifiers PA34 p re li minary external connections PA34 1234 56 7 +in -in v boost -vs i sense out +vs
apex microtechnology corporation 5980 north shannon road tucson, arizona 85741 usa applications hotline: 1 (800) 546-2739 2 absolute maximum ratings specifications absolute maximum ratings PA34 specifications parameter test conditions 2 min typ max units input offset voltage, initial 1.5 10 mv offset voltage, vs. temperature full temperature range 15 v/ c bias current, initial 35 1000 na common mode range full temperature range ? v s ? .3 +v s ? 2 db common mode rejection, dc full temperature range 60 85 db power supply rejection full temperature range 60 80 db gain open loop gain full temperature range 80 100 db gain bandwidth product a v = 40db 600 khz phase margin full temperature range 6 5 power bandwidth v o(p-p) = 28v 13.6 khz output current, peak 2.5 a current, limit 3.0 a slew rate .5 1.2 v/s capacitive load drive a v = 1 .22 f voltage swing full temp. range, i o = 100ma |v s | ? 1.0 |v s | ? 0.8 v voltage swing full temp. range, i o = 1a |v s | ? 1.8 |v s | ? 1.4 v voltage swing i o = 2.5a |v s | ? 3.0 |v s | ? 2.8 v voltage swing i o = 3.0a v power supply voltage, v ss 3 5 4 30 40 v current, quiescent, total 45 90 ma thermal resistance, dc junction to case 5.0 c/w resistence,ac junction to case 3.7 c/w resistance, junction to air 30 c/w temperature range, case meets full range speci ? cations ? 25 85 c supply voltage, total 5v to 40v output current soa power dissipation, internal (per ampli ? er) 25w input voltage, differential v s input voltage, common mode +v s , -v s ? .5v junction temperature, max 1 150 c temperature, pin solder ? 10 sec max 300 c temperature range, storage ? 65 c to 150 c operating temperature range, case ? 55 c to 125 c PA34 notes: 1. long term operation at the maximum junction temperature will result in reduced product life. derate inter nal power dissipation to achieve high mttf. 2. unless otherwise noted, the following conditions apply: v s = 15v, t c = 25 c. 3. +v s and ? v s denote the positive and negative supply rail respectively. v ss denotes the total rail-to-rail supply voltage. 4. current limit may not function properly below v ss = 6v, however soa violations are unlikely in this area.
apex microtechnology corporation telephone (520) 690-8600 fax (520) 888-3329 orders (520) 690-8601 email prodlit@apexmicrotech.com c 3 typical performance graphs PA34 0 25 50 75 100 125 temperature, t ( c) 0 5 15 25 power derating internal power dissipation, p(w) ? 50 0 100 .25 .75 1.5 1.75 bias current 1.0 .5 ? 50 0 75 125 case temperature, t ( c) normalized current limit, i (a) 1 100 1m frequency, f (hz) ? 20 0 60 small signal response open loop gain, a (db) 20 40 80 100 0 100 .1m ? 210 ? 150 ? 60 0 phase response ? 90 ? 30 1k 100k frequency, f (hz) 5 output voltage, v (v ) o 100 1k 40k frequency, f (hz) .001 3 harmonic distortion total harmonic distortion, thd (%) .1 1 .7 1.4 normalized quiescent current, i (x) 5 10 40 quiescent current total supply voltage, v (v) 15 35 01.5 2.5 output current, i (a) .5 3 output voltage swing voltage drop from supply, (v) 1.5 2.5 0 10k frequency, f (hz) 60 power supply rejection power supply rejection, psr (db) 69 77 89 100k 10 100 0 time, t ( s) pulse response output voltage, v (v) 10k o .5 3.5 0 current limit 50 .4 .8 1.0 lim 1k ? 25 25 50 75 1.25 10 40 power response pp 10k .8 .9 1 1.1 1.2 30 10 1k 10k 100k 150 20 30 10 10k 1m frequency, f (hz) phase, ( ) ? normalized bias current, i (x) b 1k 1m 63 74 83 200 400 600 800 1k ? 10 ? 5 0 5 10 o 10 15 20 25 40 50 .01 3 q 20 ss 125 case temperature, t ( c) c ? 180 ? 120 1.2 1.4 1.6 2 35 30 |+v | + | ? v | = 40v s s 66 71 80 86 a v = 1 r =10 l ? ? 25 25 100 .6 c a v = ? 10 v = 16v r = 8 out l ? 10 1.3 ? 50 ? 25 0 25 50 75 100 125 case temperature, t ( c) c 1 3.5 12 25 pp
apex microtechnology corporation 5980 north shannon road tucson, arizona 85741 usa applications hotline: 1 (800) 546-2739 4 operating considerations PA34 general please read application note 1 "general operating considerations" which covers stability, supplies, heat sinking, mounting, current limit, soa interpretation, and speci ? cation 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 speci ? c 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. current limit current limit is internal to the ampli ? er, the typical value is shown in the current limit speci ? cation. 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 capacitive load inductive load 20v 200f 7.5mh 15v 500f 25mh 10v 5mf 35mh 5v 50mf 150mh * 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 ampli ? er 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 ? yback, 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 dif ? cult for the op amp manufacturer to optimize compensation for all operating conditions. the recommended r-c network of 1 ohm in series with 0.1f from output to ac common (ground or a supply rail, with adequate bypass capacitors) will prevent local output stage oscillations. the ampli ? ers are internally compensated for unity gain stability, no additional compensation is required. thermal considerations the PA34 may require a thermal washer which is electrically insulating since the tab is tied to ? v s . this can result in thermal impedances for r cs of up to 1 c/w or greater. additional PA34 pin functions v boost the v boost pin is the positive terminal for the load of the second stage of the ampli ? er. when that terminal is connected to a voltage greater than +v s 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 v boost is about 5 volts greater than +v s the positive output can swing 0.5 volts closer to the rail. this is as much improvement as is possible. 3 2 1 .1 1 2 3 4 5 6 10 20 30 50 supply to output differential voltage v ? v (v) so output current from +v or ? v (a) ss 40 4 t = 25 c c 1 ms dc ? in +in ? v s r s i sense out v boost +v s figure 2. equivalent schematic
apex microtechnology corporation telephone (520) 690-8600 fax (520) 888-3329 orders (520) 690-8601 email prodlit@apexmicrotech.com c 5 operating considerations PA34 v boost pin requires approximately 10 ? 12ma of current. dynamically it represents 1k ? impedance. the maximum voltage that can be applied to v boost is 40 volts with respect to ? v s . there is no limit to the difference between +v s and v boost . figure 3 shows a bootstrap which dynamically couples the output waveform onto the v boost pin. this causes v boost to swing positive from it's initial value, which is equal to +v s -0.7 v (one diode drop), an amount equal to the output. in other words, if v boost was initially 19.3, and the output swings positive 18 volts, the voltage on the v boost pin will swing to 19.3 -0.7 + 18 or 36.6. the capacitor needs to be sized based on a 1k ? impedance and the lowest frequency required by the circuit. for example, 20hz will require > 8uf. i sense the i sense pin is in series with the negative half of the output stage only. current will ? ow through this pin only when negative current is being outputted. the current that ? ows in this pin is the same current that ? ows in the output (if ? 1a ? ows in the output, the i sense pin will have 1a of current ? ow, if +1a ? ows in the output the i sense pin will have 0 current ? ow). 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 ? 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 PA34 i sense feature being used to obtain a transconductance function. in this example, ampli ? er "a" is the master and ampli ? er "b" is the slave. feedback from sensing resistors r s is applied to the summing network and scaled to the inverting input of ampli ? er "a" where it is compared to the input voltage. the current sensing feedback imparts a transconductance feature to the ampli ? ers 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: i l = (v in ? v ref ) *r in / r fb / r s in the illustration, resistors r in , r fb and r s determine gain. v bias should be set midway between +v s and -v s , 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 PA34 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 ? xed terminals. 4. strain relief must be provided if there is any probability of axial stress to the leads. 10 3 7 5 8 +v s 20v d b1 d b2 c b1 speaker c b2 figure 3. simple bootstrapping improves positive output swing. connect pins 3 and 10 to v s if not used. typical currents are 12 m a each. a b v bias +v s v in v ref ? v s or gnd r s r s i l r l r in r in r r r fb r fb figure 4. i sense transconductance bridging amplifier this data sheet has been carefully checked and is believed to be reliable, however, no responsibility is assumed for possible i naccuracies or omissions. all speci cations are subject to change without notice. PA34u rev. 1 january 2001? 2001 a p ex microtechnolo gy cor p .
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