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3BlockDescription
3.1BlockA
3.2BlockB
3.3BlockC
3.4BlockD
4Software-SelectableOptions
BlockDescription
ThissectiondiscussesthefourEVMblocks.
BlockAincludesaCDCE421QFNdevicethatacceptsanLVCMOSreferenceinputthroughthevertical
SMAinputconnector(RefInput)whichisac-coupledontotheboard.
ThisblockincludesaCDCE421QFNdevicethatusesanAT-cutcrystal.Thisblockcanbeusedaseither
anXOoraVCXO.ForuseasanXOorVCXO,thecrystalshouldbemountedoneitherofthetwocrystal
footprintsontheboard.AverticalSMAinputconnectormustalsobeinstalledontheprovidedfootprintto
beusedasthecontrolvoltageinputforuseasaVCXO.
BlockCincludesaCDCE41deviceinitsbaredieform,packagedwithina5x7oscillator.Theoscillator
packagealsoincludesafixedfrequencycrystalwithaspecifiedloadandrange.Oscillatorswithdifferent
frequencycrystalsthatcontainaCDCE421devicecanbeobtainedthroughPletronics.
Thefourthblock,D,includesasocketfittingtheoscillatorpartusedinBlockC.
TheprovidedEVMsoftwareiscontrolledthroughagraphicaluserinterface(GUI).Thesoftwareallows
userstoeasilysendcommandstotheCDCE421throughthehost-poweredUSBinterface.TheEVM
includesaslaveUSBcontrollerthattransmitsthecommandstothesingle-pinprogramminginterface
includedontheCDCE421.DCpowerfortheUSBcontrollercanbeprovidedeitherfromthe5Vpowerpin
intheUSBcableorbyusinganexternal5Vacadapter(pluggedintotheslotavailableontheEVM).
InadditiontowritingcommandstotheCDCE421SRAMwhiletheboardispowered,softwarecommands
canalsobestoredineitherthenonvolatileUSBmicrocontrollermemoryortheEEPROMincludedwithin
theCDCE421.ThisarchitectureallowsuserstostarttheEVMinthedesiredstatewithoutrequiring
additionalprogrammingatpower-up.
NotethattheCDCE421doeshaveapermanentEEPROMlockmode.Whenthismodeisselected,the
embeddedEEPROMintheCDCE421cannotbechanged.Thismodeisusefulwhensettingfinal
configurations.
SCAU020–March200710.9MHz–1175MHzLowPhaseNoiseClockEvaluationBoard7
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