apex microtechnology corporation ?telephone (520) 690-8600 ?fax (520) 888-3329 ?orders (520) 690-8601 ?email prodlit@apexmicrotech.com features high voltage ?900v ( 450v) high slew rate ?500v/ s high output current ?100ma programmable current limit applications high voltage instrumentation programmable power supplies up to 430v mass spectrometers semiconductor measurement equipment description the PA94 is a high voltage, mosfet operational amplifier designed as a low cost solution for driving continuous output currents up to 100ma and pulse currents up to 200ma into capacitive loads. the safe operating area (soa) has no second breakdown limitations and can be observed for all load types by choosing an appropriate current limiting resistor. the mosfet output stage is biased ab for linear operation. external compensation provides flexibility in choosing band- width and slew rate for the application. apex? power sip04 package uses a minimum of board space allowing for high density circuit boards. equivalent schematic typical application piezo positioning may be applied to the focusing of seg- mented mirror systems. the composite mirror may be com- posed of hundreds of elements, each requiring focusing under computer control. in such complex systems the PA94 reduces the costs of power supplies and cooling with its advantages of low cost and low quiescent power consumption while increas- ing circuit density with the sip package. external connections package sip04 q1 q2 r1 r2 c1 12 r3 q3 cc1 cc2 q6 q5 r5 r8 2 1 r9 q15 r11 10 r12 q16 q12 q8 r4 r7 7 8 6 4 q4 ilim out q14 r10 q13 q11 +v s in +in v s r6 12 4 678 10 12 ** * .01 f or greater ceramic power supply bypassing required. in +in cc1 cc2 out i lim vs +vs c c r lim patent pending http://www.apexmicrotech.com (800) 546-apex (800) 546-2739 microtechnology high voltage power operational amplifier PA94 f r PA94 in r piezo drive s v s +v out v computer focus command voltage cl r 1 2 10 8 7 12 phase compensation gain c c 100 50 10 2.2pf 4.7pf 22pf r lim = .7 i lim
apex microtechnology corporation 5980 north shannon road tucson, arizona 85741 usa applications hotline: 1 (800) 546-2739 absolute maximum ratings specifications absolute maximum ratings supply voltage, +v s to v s 900v output current, source, sink 200ma, within soa power dissipation, continuous @ t c = 25 c 30w input voltage, differential 20v input voltage, common mode 3 v s temperature, pin solder - 10s max 220 c temperature, junction 2 150 c temperature, storage 65 to +150 c operating temperature range, case 55 to +125 c PA94 specifications parameter test conditions 1 min typ max units input offset voltage, initial .5 5 mv offset voltage, vs. temperature full temperature range 15 50 v/ c offset voltage, vs. supply 10 25 v/v offset voltage, vs. time 75 v/ kh bias current, initial 200 2000 pa bias current, vs. supply 4 pa/v offset current, initial 50 500 pa input impedance, dc 10 11 ? input capacitance 4pf common mode voltage range 3 vs= 250v see note 3 v s 30 v common mode rejection, dc v cm = 90v 80 98 db noise 10khz bw, r s = 1k ? 2 vrms gain open loop, @ 15hz r l = 5k ? 94 115 db gain bandwidth product at 1mhz r l = 5k ? 140 mhz power bandwidth r l = 5k ? 300 khz phase margin, av=100 full temperature range 60 output voltage swing i o = 100ma v s 24 v s 20 v current, continuous 100 ma slew rate, a v = 100 c c =2.2pf 500 700 v/ s settling time to .1% 2v step 1 s resistance no load 100 ? power supply voltage 5 see note 5 50 300 450 v current, quiescent total 17 24 ma current, quiescent output stage only 120 a thermal resistance, ac, junction to case 4 full temperature range, f > 60hz 2.5 c/w resistance, dc, junction to case full temperature range, f < 60hz 4.2 c/w resistance, junction to air full temperature range 30 c/w temperature range, case meets full range specifications 25 +85 c notes: 1. unless otherwise noted: t c = 25 c, dc input specifications are value given. power supply voltage is typical rating. c c = 4.7pf. 2. long term operation at the maximum junction temperature will result in reduced product life. derate internal power dissipatio n to achieve high mttf. 3. although supply voltages can range up to 450v the input pins cannot swing over this range. the input pins must be at least 30v from either supply rail but not more than 500v from either supply rail. see text for a more complete description of the common mode voltage range. 4. rating applies if the output current alternates between both output transistors at a rate faster than 60hz. 5. derate max supply rating .625 v/ c below 25 c case. no derating needed above 25 c case. caution the PA94 is constructed from mosfet transistors. esd handling procedures must be observed.
apex microtechnology corporation telephone (520) 690-8600 fax (520) 888-3329 orders (520) 690-8601 email prodlit@apexmicrotech.com typical performance graphs PA94 with the unique combination of high voltage and speed of the PA94, traditional formulas for heatsink selection will falsely lower the apparent power handling capability of this amplifier. to more accurately predict operating temperatures use power design 1 revision 10 or higher, or use the following procedure: find internal dissipation (pd) resulting from driving the load. use power design or refer to apex applications note 1, general operating considertaions, paragraph 7. find total quiescent power (pd q ) by multiplying 0.024a by v ss (total supply voltage). find output stage quiescent power (pd qout ) by multiplying 0.00012 by v ss . calculate a heatsink rating which will maintain the case at 85 c or lower. internal power dissipation and heatsink selection where: t c = maximum case temperature allowed t a = maximum ambient temperature encountered calculate a heatsink rating which will maintain output transistor junctions at 150 c or lower. where: t j = maximum junction temperature allowed. r ? jc = ac or dc thermal resistance from the specification table. use the larger heatsink of these two calculations. power design is an excel spreadsheet available free from www.apexmicrotech.com r ? sa = tc - ta pd + pd q - 0.1 c/w r ? sa = t j - ta - (pd + pd qout ) *r ? jc pd + pd q -0.1 c/w 0 25 50 75 100 125 150 temperature, t ( c) 0 5 15 20 power derating internal power dissipation, p(w) 10 100 10k 1m frequency, f (hz) 0 100 output current, i (ma) 4 8 16 24 output voltage swing 12 20 3 10 20 100 current limit resistor, r cl ( ) 10 30 200 current limit current limit, i (ma) lim 50 70 550 20 input noise 1k 2 7 10 20 3 5 15 o 20 voltage drop from supply, v v (v) so 10 30 ? 60 25 40 120 100 150 t = 25 c c t = 55 c c t = 125 c c t = 85 c c 80 t = t c t = t a safe operating area supply to output differential, v s v o (v) 50 50 output current from +v s or v s , (ma) 5 10 15 25 dc, t c = 125 c dc , t c = 85 c 200ms pulse curves @ 10% duty cycle max dc, t c = 25 c 100ms 100 100 150 200 250 500 1k 0 200 600 800 1000 total supply voltage, v (v) 1.08 1.04 1.00 .96 .92 .88 quiescent current quiescent current, i(x) s 400 input noise voltage, v n (nv/ hz) 1m 20m 10m frequency, f (hz) -90 -120 -150 -180 -210 -240 phase response phase, ( ) power response 100k 1m 2m frequency, f (hz) 10k 50 1k 500 output voltage, v (v ) o p-p 100 200 frequency, f (hz) small signal response open loop gain, a (db) 0 60 120 20 40 80 100 10 100 1k 10k 1m 100k 20m 10m c c = 22 pf c c = 2.2pf c c = 4.7pf c c = 22 pf c c = 4.7pf c c = 2.2pf c c = 22 pf c c = 4.7pf c c = 2.2pf
apex microtechnology corporation 5980 north shannon road tucson, arizona 85741 usa applications hotline: 1 (800) 546-2739 general please read application note 1 "general operating consid- erations" which covers stability, supplies, heat sinking, mount- ing, current limit, soa interpretation, and specification inter- pretation. visit www.apexmicrotech.com for design tools that help automate tasks such as calculations for stability, internal power dissipation, current limit; heat sink selection; apex s complete application notes library; technical seminar work- book; and evaluation kits. current limit for proper operation, the current limit resistor (r lim ) must be connected as shown in the external connection diagram. the minimum value is 3.5 ohm, however for optimum reliability the resistor value should be set as high as possible. the value is calculated as follows; with the maximum practical value of 30 ohms. .7 r lim = i lim common mode input range operational amplifiers are usually designed to have a com- mon mode input voltage range that approximates the power supply voltage range. however, to keep the cost as low as possible and still meet the requirements of most applications the common mode input voltage range of the PA94 is re- stricted. the input pins must always be a least 30v from either supply voltage but never more than 500v. this means that the PA94 cannot be used in applications where the supply volt- ages are extremely unbalanced. for example, supply voltages of +800v and 100v would not be allowed in an application where the non-inverting pin is grounded because in normal operation both input pins would be at 0v and the difference voltage between the positive supply and the input pins would be 800v. in this kind of application, however, supply voltages +500v and -100v does meet the input common mode voltage range requirements since the maximum difference voltage between the inputs pins and the supply voltage is 500v (the maximum allowed). the output has no such restrictions on its voltage swing. the output can swing within 24v of either supply voltage regardless of value so long as the total supply voltage does not exceed 900v. input protection although the PA94 can withstand differential input voltages up to 20v, additional external protection is recommended. in most applications 1n4148 or 1n914 signal diodes are suffi- cient (d1, d2 in figure 1a). in more demanding applications where low leakage or low capacitance are of concern 2n4416 or 2n5457-2n5459 jfets connected as diodes will be re- quired (q1, q2 in figure 1b). in either case the input differential voltage will be clamped to .7v. this is sufficient overdrive to produce maximum power bandwidth. note that this protection does not automatically protect the amplifier from excessive common mode input voltages. power supply protection unidirectional zener diode transient suppressors are recom- mended as protection on the supply pins. the zeners clamp transients to voltages within the power supply rating and also clamp power supply reversals to ground. whether the zeners are used or not, the system power supply should be evaluated for transient performance including power-on overshoot and power-off polarity reversal as well as line regulation. conditions which can cause open circuits or polarity rever- sals on either power supply rail should be avoided or protected against. reversals or opens on the negative supply rail is known to induce input stage failure. unidirectional transzorbs prevent this, and it is desirable that they be both electrically and physically as close to the amplifier as possible. stability the PA94 is stable at gains of 100 or more with a npo (cog) compensation capacitor of 2.2pf. the compensation capacitor, cc, in the external connections diagram must be rated at 1000v working voltage and mounted closely to pins 4 and 6 to prevent spurious oscillation. a compensation capaci- tor less than 2.2pf is not recommended. external components the compensation capacitor cc must be rated for the total supply voltage. an npo (cog) capacitor rated a 1kv is recommended. of equal importance are the voltage rating and voltage coefficient of the gain setting feedback resistor. typical volt- age ratings of low wattage resistors are 150 to 250v. up to 500 v can appear across the feedback resistor. high voltage rated resistors can be obtained. however a 1 megohm feedback resistor composed of five 200k resistors in series will produce the proper voltage rating. cautions the operating voltages of the PA94 are potentially lethal. during circuit design develop a functioning circuit at the lowest possible voltages. clip test leads should be used for "hands off" measurements while troubleshooting. figure 1. overvoltage protection PA94 +v s in +in z1 z2 d2 d1 12 10 1 2 +v s in +in z1 z2 12 10 1 2 PA94 q1 q2 a. b. v s v s 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 specifications are subject to change without notice. PA94u rev. c august 2000 ? 2000 apex microtechnology corp. PA94 operating considerations
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