6

PA93/27U

P r o d u c t I n n o v a t i o n F r o m

PA93/27

POWER SUPPLY PROTECTION

Unidirectionalzenerdiodetransientsuppressorsarerecommendedas

protectiononthesupplypins.SeeFigure2.Thezenersclamptransients

tovoltageswithinthepowersupplyratingandalsoclamppowersupply

reversals to ground. Whether the zeners are used or not, the system

powersupplyshouldbeevaluatedfortransientperformanceincluding

power-onovershootandpower-offpolarityreversalsaswellaslineregu-

lation.

Conditionswhichcancauseopencircuitsorpolarityreversalsoneither

powersupplyrailshouldbeavoidedorprotectedagainst.Reversalsor

opensonthenegativesupplyrailisknowntoinduceinputstagefailure.

Unidirectional transzorbs prevent this, and it is desirable that they be

bothelectricallyandphysicallyasclosetotheamplifieraspossible.

STABILITY

ThePA93/27isexternallycompensatedandperformancecanbetailoredtotheapplication.Usethegraphsofsmall

signalresponseandpowerresponseasaguide.ThecompensationcapacitorC

voltage.AnNPOcapacitorisrecommended.ThecompensationnetworkC

plifierpins4and5toavoidspuriousoscillation.

QUIESCENT CURRENT REDUCTION

Whenpin3(I

butalsoraisesdistortionsincetheoutputstageisthenclassCbiased.Theoutputstagebiascurrentisnominally

setat1mA.Pin3maybeleftopenifnotused.

–IN

+IN

Z1

Z2

11, 12

7, 8

1

2

6

PA93

Q1

Q2

Q3

Q4

FIGURE 2.

OVERVOLTAGE

PROTECTION

CONTACTING CIRRUS LOGIC SUPPORT

ForallApexPrecisionPowerproductquestionsandinquiries,calltollfree800-546-2739inNorthAmerica.

Forinquiriesviaemail,pleasecontacttucson.support@cirrus.com.

InternationalcustomerscanalsorequestsupportbycontactingtheirlocalCirrusLogicSalesRepresentative.

Tofindtheonenearesttoyou,gotowww.cirrus.com

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