PA341
PA341U 1
PA341
FEATURES
♦ RoHSCOMPLIANT
♦ MONOLITHICMOSTECHNOLOGY
♦ LOWCOST
♦ HIGHVOLTAGEOPERATION–350V
♦ LOWQUIESCENTCURRENTTYP.–2.2mA
♦ NOSECONDBREAKDOWN
♦ HIGHOUTPUTCURRENT–120mAPEAK
♦ AVAILABLEINDIEFORM–CPA341
APPLICATIONS
♦ PIEZOELECTRICPOSITIONING
♦ ELECTROSTATICTRANSDUCER
ANDDEFLECTION
♦ DEFORMABLEMIRRORFOCUSING
♦ BIOCHEMISTRYSTIMULATORS
♦ COMPUTERTOVACUUMTUBEINTERFACE
DESCRIPTION
ThePA341isahighvoltagemonolithicMOSFETop-
erationalamplierwhichachievesperformancefea-
tures previously found only in hybrid designs while
increasing reliability. Inputs are protected from ex-
cessive common mode and differential mode volt-
ages.Thesafeoperatingarea(SOA)hasnosecond
breakdown limitation and can be observed with all
typeloadsbychoosinganappropriatecurrentlimit-
ingresistor.Externalcompensationprovidestheuser
exibilityinchoosingoptimumgainandbandwidthfor
theapplication.
ThePA341CEispackagedinahermeticallysealed
8-pinTO-3package.ThemetalcaseofthePA341CE
isisolatedinexcessoffullsupplyvoltage.
ThePA341DFispackagedina24pinPSOP(JEDEC
MO-166) package. The metal heat slug of the
PA341DFisisolatedinexcessoffullsupplyvoltage.
The PA341DW is packaged inApex Microtechnolo-
gy’shermeticceramicSIPpackage.Thealuminace-
ramicisolatesthedieinexcessoffullsupplyvoltage.
High Voltage Power Operational Amplifier
PA341
FIGURE1.EquivalentSchematic
ILIM
OUT
-IN
+IN
+VS
-VS
CC2
CC1
Copyright © Apex Microtechnology, Inc. 2012
(All Rights Reserved)
www.apexanalog.com OCT2012
PA341UREVC
PA341
2 PA341U
TYPICALAPPLICATION
Ref:APPLICATIONNOTE20:"BridgeModeOperationofPowerAmpliers"
TwoPA341ampliersoperatedasabridgedriverforapiezotransducerprovidesalowcost660volttotaldrive
capability.TheRNCNnetworkservestoraisetheapparentgainofA2athighfrequencies.IfRNissetequaltoRthe
amplierscanbecompensatedidenticallyandwillhavematchingbandwidths.
FIGURE3.ExternalConnections.
PA341DW
ForCCvalues,seegraphonpage7.
Note:CCmustberatedforfullsupplyvoltage.
NOTE:PA341CERecommendedmountingtorqueis4-7in•lbs(.45-.79N•m)
CAUTION:Theuseofcompressible,thermallyconductiveinsulatorsmayvoidwarranty.
PA341CE PA341DF
8-PINTO-3 24-PINPSOP 10-PINSIP
PACKAGESTYLECEPACKAGESTYLEDFPACKAGESTYLEDW
RCL
TOP VIEW
1
23
4
5
6
7
8
OUT
ILIM
–VS
+VS
CC1
–IN
+IN
CC2CC
CCRCL
NC
NC
NC
NC
-IN
NC
+IN
NC
NC
NC
NC
-VS
NC
NC
NC
OUT
NC
COMP
NC
COMP
NC
ILIM
NC
+VS
24
1
+
-
RCL
1 4 5 6 732 8 9 10
CC
+IN-IN
NC NC -VS+VSILIM CC2 CC1 OUT
FIGURE2.PackageStyles
20R
PIEZO
TRANSDUCER
20R
Rn
20R
Cn
R
VIN
–175
+175
–175
+175
RCL
RCL
47 47
10pF 10pF
A1
PA341
A2
PA341
FIGURE4.LowCost660VP-PPiezoDriver
PA341
PA341U 3
Parameter
Test
Conditions
(Note1)
PA341CE,PA341DF PA341DW
UnitsMin Typ Max Min Typ Max
INPUT
OFFSETVOLTAGE,initial 12 40 12 40 mV
OFFSETVOLTAGE,
vs.temperature(Note3) 25°to85°C 17 250 17 250 µV/°C
OFFSETVOLTAGE,
vs.temperature(Note3) -25°to25°C 18 500 18 500 µV/°C
OFFSETVOLTAGE,vs.supply 4.5 4.5 µV/V
OFFSETVOLTAGE,vs.time 80 80 µV/kh
BIASCURRENT,initial(Note6) 5/50 50/200 100 2000 pA
BIASCURRENT,vs.supply 0.2/2 15 50 pA/V
OFFSETCURRENT,initial(Note6) 2.5/50 50/200 100 400 pA
INPUTIMPEDANCE,DC 1011 1011 Ω
INPUTCAPACITANCE 3 3 pF
COMMONMODE,voltagerange +VS-12 +VS-12 V
COMMONMODE,voltagerange -VS+12 -VS+12 V
COMMONMODEREJECTION,DC VCM=±90VDC 84 115 84 115 dB
NOISE,broadband 10kHzBW,
RS=1K 337 337 µV
RMS
GAIN
OPENLOOPat15Hz RL=5K 90 103 90 103 dB
BANDWIDTH,gainbandwidth
product @1MHz 10 10 MHz
POWERBANDWIDTH 280Vp-p 35 35 kHz
Parameter
PA341CE PA341DF PA341DW
UnitsMin Max Min Max Min Max
SUPPLYVOLTAGE,+VS to –VS350 350 350 V
OUTPUTCURRENT, continuous within SOA 60 60 60 mA
OUTPUTCURRENT,peak 120 120 120 mA
POWERDISSIPATION,
continuous@TC=25°C
12 12 9 W
INPUTVOLTAGE,differential -16 +16 -16 +16 -16 +16 V
INPUTVOLTAGE,commonmode -VS+VS-VS+VS-VS+VSV
TEMPERATURE,pinsolder-10sec 350 220 220 °C
TEMPERATURE,junction(Note2) 150 150 150 °C
TEMPERATURE,storage -65 150 -65 150 -65 150 °C
TEMPERATURERANGE,powered(case) -40 125 -40 125 -40 125 °C
1.CHARACTERISTICSANDSPECIFICATIONS
ABSOLUTEMAXIMUMRATINGS
SPECIFICATIONS
PA341
4 PA341U
Parameter
Test
Conditions
(Note1)
PA341CE,PA341DF PA341DW
UnitsMin Typ Max Min Typ Max
OUTPUT
VOLTAGESWING IO=40mA ±VS-12 ±VS-10 ±VS-12 ±VS-10 V
CURRENT,peak(Note4) 120 120 mA
CURRENT,continuous 60 60 mA
SETTLINGTIMEto.1% 10Vstep,
AV=-10 2 2 µS
SLEWRATE CC=4.7pF 32 32 V/µS
RESISTANCE,10mA(Note5) RCL=0 91 91 Ω
RESISTANCE,40mA(Note5) RCL=0 65 65 Ω
POWERSUPPLY
VOLTAGE ±10 ±150 ±175 ±10 ±150 ±175 V
CURRENT,quiescent 2.2 2.5 2.2 2.5 mA
THERMAL
PA341CERESISTANCE,
ACjunctiontocase F>60Hz 5.4 6.5 °C/W
PA341DFRESISTANCE,
ACjunctiontocase F>60Hz 6 7 °C/W
PA341DWRESISTANCE,
ACjunctiontocase F>60Hz 7 10 °C/W
PA341CERESISTANCE,
DCjunctiontocase F<60Hz 9 10.4 °C/W
PA341DFRESISTANCE,
DCjunctiontocase F<60Hz 9 11 °C/W
PA341DWRESISTANCE,
DCjunctiontocase F<60Hz 12 14 °C/W
PA341CERESISTANCE,
junctiontoair
FullTempera-
tureRange 30 °C/W
PA341DFRESISTANCE,
junctiontoair(Note7)
FullTempera-
tureRange 25 °C/W
PA341DWRESISTANCE,
junctiontoair
FullTempera-
tureRange 30 °C/W
TEMPERATURERANGE,case Meetsfull
rangespec's -25 +85 -25 +85 °C
NOTES: 1. UnlessotherwisenotedTC=25°C,CC=6.8pF.DCinputspecicationsare±valuegiven.Powersup-
plyvoltageistypicalrating.
2. Longtermoperationatthemaximumjunctiontemperaturewillresultinreducedproductlife.Derate
internalpowerdissipationtoachievehighMTTF.Forguidance,refertoheatsinkdatasheet.
3. Sampletestedbywaferto95%.
4. Guaranteedbutnottested.
5. TheselectedvalueofRCLmustbeaddedtothevaluesgivenfortotaloutputresistance.
6. Specicationsseparatedby/indicatevaluesforthePA341CEandPA341DFrespectively.
7. Ratingapplieswithsolderconnectionofheatslugtoaminimum1squareinchfoilareaoftheprinted
circuitboard.
ThePA341isconstructedfromMOSFETtransistors.ESDhandlingproceduresmustbeobserved.
CAUTION
PA341
PA341U 5
0
5
10
15
20
25
30
0 20 40 60 80 100 120
VDROP FROM VS, (V)
OUTPUT CURRENT, IO, (mA)
OUTPUT VOLTAGE SWING
VDROP-@27°C
VDROP+@85°C
VDROP-@85°C
VDROP+@27°C
40
50
60
70
80
90
100
POWER SUPPLY REJECTION, PSR (dB)
FREQUENCY, F (Hz)
POWER SUPPLY REJECTION
10 100K10K1K100
POSITIVE
NEGATIVE
0
20
40
60
80
100
120
COMMON MODE REJECTION, CMR (dB)
FREQUENCY, F (Hz)
COMMON MODE REJECTION
10 100K10K1K100
96
98
100
102
20 60 100 140 180 220 260 300 340
NORMALIZED QUIESCENT CURRENT (%)
TOTAL SUPPLY VOLTAGE, (V)
QUIESCENT CURRENT
-40°C
25°C
125°C
0
10
20
30
5 15 25 35 45 55 65 75 85
SLEW RATE, (V/µs)
COMPENSATION CAPACITANCE, C
C
(pF)
SLEW RATE
RISE
FALL
DISTORTION, (%)
FREQUENCY, F (Hz)
HARMONIC DISTORTION
30VP-P
60VP-P
180VP-P
A V = 20
C C = 15pF
R L = 2K
0.001
10
1
0.1
0.01
100 100K10K1K
10
100
1000
10K 100K 1M
OUTPUT VOLTAGE, VOUT (P-P)
FREQUENCY, F (Hz)
POWER RESPONSE
33pF
2.2pF
6.8pF
15pF
68pF
-180
-170
-160
-150
-140
-130
-120
-110
-100
-90
10K 100K 1M 10M
PHASE, Φ (°)
FREQUENCY, F (Hz)
PHASE RESPONSE
2.2pF
68pF
6.8pF
15pF
0.75pF
-80
-20
0
20
40
60
80
100
OPEN LOOP GAIN, A (dB)
FREQUENCY, F (Hz)
SMALL SIGNAL RESPONSE
0.75pF
68pF
15pF
6.8pF
2.2pF
10 10M1M100K10K1K100
0.1
1
10
100
101
COMPENSATION, pF
GAIN
GAIN AND COMPENSATION
0.1
125°C
85°C
55°C
25°C
0.50
0.55
0.60
0.65
0.70
0.75
0.80
0.85
-40 -20 0 20 40 60 80 100 120
V
BE
(V)
TEMPERATURE (°C)
VBE for ILIMIT
VBE+
VBE-
0 25 50 75 100 125
TEMPERATURE, T (°C)
0
3
6
POWER DERATING
INTERNAL POWER DISSIPATION, P (W)
15
9
12
PA341CE
PA341DF
T = TA
T = TC
T = TA
T = TC
PA341DW
2. TYPICALPERFORMANCEGRAPHS
PA341
6 PA341U
3. APPLICATIONSINFORMATION
PleasereadApplicationNote1"GeneralOperatingConsiderations"whichcoversstability,powersupplies,heat
sinking, mounting, current limit, SOA interpretation, and specication interpretation. Visit www.apexanalog.com
fordesigntoolsthathelpautomatetaskssuchascalculationsforstability,internalpowerdissipation,currentlimit,
heatsinkselection,ApexMicrotechnology'scompleteApplicationNoteslibrary,TechnicalSeminarWorkbookand
EvaluationKits.
3.1 PHASECOMPENSATION
Openloopgainandphaseshiftbothincreasewithincreasingtemperature.ThePHASECOMPENSATIONtypical
graphshowsclosedloopgainandphasecompensationcapacitorvaluerelationshipsforfourcasetemperatures.
Thecurvesarebasedonachievingaphasemarginof50°.Calculatethehighestcasetemperaturefortheapplica-
tion(maximumambienttemperature and highestinternalpowerdissipation)beforechoosingthecompensation.
Keepinmindthatwhenworkingwithsmallvaluesofcompensation,parasiticsmayplayalargeroleinperformance
ofthenishedcircuit.Thecompensationcapacitormustberatedforatleastthetotalvoltageappliedtotheamplier
andshouldbeatemperaturestabletypesuchasNPOorCOG.
3.2 OTHERSTABILITYCONCERNS
Therearetwoimportantconceptsaboutclosedloopgainwhenchoosingcompensation.Theystemfromthefact
thatwhile"gain"isthemostcommonlyusedterm,β (thefeedbackfactor)isreallywhatcountswhendesigningfor
stability.
1. Gainmustbecalculatedasanon-invertingcircuit(equalinputandfeedbackresistorscanprovideasignalgain
of-1,butforcalculatingoffseterrors,noise,andstability,thisisagainof2).
2. Includingafeedbackcapacitorchangesthefeedbackfactororgainofthecircuit.ConsiderRIN=4.7k,RF=47kfor
againof11.Compensationof4.7to6.8pFwouldbereasonable.Adding33pFparalleltothe47Krollsoffthe
circuitat103kHz,andat2MHzhasreducedgainfrom11toroughly1.5andthecircuitislikelytooscillate.
AsageneralruletheDCsummingjunctionimpedance(parallelcombinationofthefeedbackresistorandallinput
resistors)shouldbelimitedto5kohmsorless.Theamplierinputcapacitanceofabout6pF,pluscapacitanceof
connectingtracesorwiresand(ifused)asocketwillcauseundesirablecircuitperformanceandevenoscillationif
theseresistancesaretoohigh.Incircuitsrequiringhighresistances,measureorestimatethetotalsumpointca-
pacitance,multiplybyRIN/RF,andparallelRFwiththisvalue.Capacitorsincludedforthispurposeareusuallyinthe
singledigitpFrange.ThistechniqueresultsinequalfeedbackfactorcalculationsforACandDCcases.Itdoesnot
producearolloff,butmerelykeepsβconstantoverawidefrequencyrange.Paragraph6ofApplicationNote19
detailssuitablestabilitytestsforthenishedcircuit.
3.3 CURRENTLIMIT
Forproperoperation,thecurrentlimitingresistor,RCL,mustbeconnectedasshowninFigure3,“ExternalConnec-
tions”.Thecurrentlimitcanbepredictedasfollows:

ILIMIT = VBE
RCL
The“VBEforILIMIT”performancegraphisusedtondVBE.Onthisgraph,theVBE+andVBE−curvesshowthevoltages
acrossthecurrentlimitingresistoratwhichcurrentlimitingisturnedon.TheVBE+curveshowstheseturn-onvolt-
ageswhentheamplierissourcingcurrent,andtheVBE−curveshowsthesevoltageswhentheamplierissinking
current.
Thecurrentlimitcanbethoughtofasaceilingorlimitforsafeoperation.Forcontinuousoperationitisanyvalue
betweenthedesiredloadcurrentand60mA(aslongasthecurvesontheSOAgrapharenotexceeded,please
PA341
PA341U 7
refertosection3.4forinformationontheSOAgraph).Asanexample,supposethedesiredloadcurrentfortheap-
plicationis20mA.Inthiscasewemaysetacurrentlimitof30mA.StartingwiththesmallerVBE
−of0.6wehave:

RCL = = 20Ω
0.6
1.03
ForthelargerVBE
+thisRCLresistorwillallowforamaximumcurrentof:

ILIMIT = = 35mA
0.7
20
Thisvalueisstillacceptablebecauseitislessthan60mA.Forthecaseofcontinuousloadcurrents,checkthatthe
currentlimitdoesnotexceed60mA.
TheVBEvaluesusedaboveareapproximateandcanvary
withprocess.Toallowforthispossibilitytheusercanreduce
theVBE =0.6 valueby 20%.This results in a RCLvalue of
16Ω.UsingthissameRCLvalueandallowingfora20%in-
creaseintheotherVBE,thecurrentlimitmaximumis52mA.
The absolute minimum value of the current limiting resis-
torisboundedbythelargestcurrentandthelargestVBEin
theapplication.ThelargestVBEisdeterminedbythecoldest
temperatureintheapplication.IngeneralthelargestVBEis
VBE+=0.78,whichoccursatT=−40°C.Thelargestallowed
currentoccursinpulsedapplicationswhere,fromtheSOA
graph,wecanseecurrentpulsesof120mA.Thisgivesus
anabsoluteminimumRCLvalueof0.78/0.12=6.5Ω.
3.4 SAFEOPERATINGAREA
The MOSFET output stage of the PA341 is not limited by
secondbreakdownconsiderationsasinbipolaroutputstag-
es.Howevertherearestillthreedistinctlimitations:
1. Voltagewithstandcapabilityofthetransistors.
2. Currenthandlingcapabilityofthediemetalization.
3. TemperatureoftheoutputMOSFETS.
TheselimitationscanbeseenintheSOA(seeSafeOperat-
ingAreagraphs).Notethateachpulsecapabilitylineshows
a constant power level (unlike second breakdown limita-
tionswherepower varieswith voltage stress).Theselines
areshownforacasetemperatureof25°Candcorrespond
tothermalresistancesof5.2°C/WforthePA341CEandDF
and10.4°C/WforthePA341DWrespectively.Pulsestress
levelsforothercasetemperaturescanbecalculatedinthe
samemannerasDCpowerlevelsatdifferenttemperatures.
The output stage is protected against transient yback by
theparasiticdiodesoftheoutputstageMOSFETstructure.
However, for protection against sustained high energy y-
backexternalfast-recoverydiodesmustbeused.
SUPPLY TO OUTPUT DIFFERENTIAL, VS -VO (V)
10 20 30 50 100 200 300 500
OUTPUT CURRENT FROM +VS OR –VS, (mA)
2
3
4
5
10
20
30
40
50
100
DC, TC = 125°C
DC, T
C
= 85°C
DC
PULSE CURVES @ 10% DUTY CYCLE MAX
PA341CE and DF SOA
200mS
120
200
SUPPLY TO OUTPUT DIFFERENTIAL, VS -VO (V)
10 20 30 50 100 200 300 500
OUTPUT CURRENT FROM +VS OR –VS, (mA)
2
3
4
5
10
20
30
40
50
100
DC, TC = 125°C
DC, T
C
= 85°C
DC
PULSE CURVES @ 10% DUTY CYCLE MAX
PA341DW SOA
200mS
120
200
FIGURE5.SafeOperatingArea
PA341
8 PA341U
3.5 HEATSINKING
ThePA341DFpackagehasalargeexposedintegratedcopperheatslugtowhichthemonolithicamplierisdirectly
attached.Thesolderconnectionoftheheatslugtoaminimumof1squareinchfoilareaontheprintedcircuitboard
willresultinthermalperformanceof25°C/WjunctiontoairratingofthePA341DF.Solderconnectiontoanareaof1
to2squareinchesisrecommended.Thismaybeadequateheatsinkingbutthelargenumberofvariablesinvolved
suggesttemperaturemeasurementsbemadeonthetopofthepackage.Donotallowthetemperaturetoexceed
85°C.
3.6 OVERVOLTAGEPROTECTION
AlthoughthePA341canwithstanddifferentialinputvoltagesupto16V,in
someapplicationsadditionalexternalprotectionmaybeneeded.Differen-
tialinputsexceeding16Vwillbeclippedbytheprotectioncircuitry.How-
ever,ifmorethanafewmilliampsofcurrentisavailablefromtheoverload
source,theprotectioncircuitrycouldbedestroyed.Fordifferentialsources
above16V,addingseriesresistancelimitinginputcurrentto1mAwillpre-
ventdamage.Alternatively,1N4148signaldiodesconnectedanti-parallel
acrosstheinputpinsisusuallysufcient.Inmoredemandingapplications
wherebiascurrentisimportant,diodeconnectedJFETssuchas2N4416
willberequired.SeeQ1andQ2inFigure6.Ineithercasethedifferential
inputvoltagewillbeclampedto0.7V.Thisissufcientoverdrivetoproduce
themaximumpowerbandwidth.
Inthecaseofinvertingcircuitswherethe+INpinisgrounded,thediodes
mentionedabovewillalsoaffordprotectionfromexcessivecommonmode
voltage.Inthecaseofnon-invertingcircuits,clampdiodesfromeachinputtoeachsupplywillprovideprotection.
Notethatthesediodeswillhavesubstantialreversebiasvoltageundernormaloperationanddiodeleakagewill
produceerrors.
Someapplicationswillalsoneedover-voltageprotectiondevicesconnectedtothepowersupplyrails.Unidirectional
zenerdiodetransientsuppressorsarerecommended.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
reversalsaswellaslineregulation.SeeZ1andZ2inFigure6.
+Vs
-Vs
OUT
+Vs
-Vs
Z1
Z2
-IN
+IN
Q1 Q2
FIGURE6.OvervoltageProtection
PA341
PA341U 9
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www.apexanalog.com OCT2012
PA341UREVC