LT5579 datasheet(9/20 Pages) LINER

9 / 20 page

LT5579

5579fa

pin FuncTions

GND(Pins1,2,5-7,12-14,16-18,19-21,23,24):Ground

Connections.Thesepinsareinternallyconnectedtothe

exposedpadandshouldbesolderedtoalowimpedance

RFgroundontheprintedcircuitboard.

IF+, IF– (Pins 3, 4):DifferentialIFInput.Thecommon

modevoltageonthesepinsissetinternallyto570mV.The

DCcurrentfromeachpinisdeterminedbythevalueof

anexternalresistortoground.ThemaximumDCcurrent

througheachpinis60mA.

VCC (Pins 8-11):PowerSupplyPinsfortheIC.These

pins are connected together internally. Typical current

consumptionis226mA.Thesepinsshouldbeconnected

togetheronthecircuitboardwithexternalbypasscapaci-

torsof1000pF,100pFand10pFlocatedasclosetothe

pinsaspossible.

RF (Pin 15):Single-EndedRFOutput.Thispiniscon-

nectedtoaninternaltransformerwinding.Theopposite

endofthewindingisgroundedinternally.Animpedance

transformationmayberequiredtomatchtheoutputanda

DCdecouplingcapacitorisrequiredifthefollowingstage

hasaDCbiasvoltagepresent.

LO(Pin22):Single-EndedLocalOscillatorInput.Aninternal

seriescapacitoractsasaDCblocktothispin.

Exposed Pad (Pin 25): PGND. Electrical and thermal

groundconnectionfortheentireIC.Thispadmustbe

solderedtoalowimpedanceRFgroundontheprinted

circuitboard.Thisgroundmustalsoprovideapathfor

thermaldissipation.

LT5579 Datasheet(PDF) 9 Page - Linear Technology