Analog Frequency Multiplier
PL560-xx VCXO Family
ꢀ
DETERMINING STRAY L’s AND C’s IN A LAYOUT
Figure 6: Diagram Representation of the Board Layout
LetsꢀtakeꢀtheꢀPL560ꢁ38ꢀ(4xꢀVCXO)ꢀforꢀexample.ꢀꢀThisꢀtakesꢀaꢀcrystalꢀinputꢀinꢀtheꢀrangeꢀofꢀ30ꢀtoꢀ80ꢀMHzꢀandꢀ
multipliesꢀitꢀtoꢀanꢀoutputꢀofꢀ120ꢀtoꢀ320ꢀMHz.ꢀꢀToꢀdetermineꢀtheꢀstrayꢀL’sꢀandꢀC’sꢀofꢀtheꢀlayoutꢀweꢀwillꢀassembleꢀ
twoꢀtestꢀunits.ꢀꢀOneꢀAFMꢀwillꢀbeꢀtunedꢀtoꢀtheꢀlowerꢀrangeꢀofꢀtheꢀdeviceꢀ(120ꢀMHz),ꢀandꢀtheꢀotherꢀtoꢀtheꢀupperꢀ
rangeꢀofꢀtheꢀdeviceꢀ(320ꢀMHz).ꢀꢀꢀ
ꢀ
120 MHz AFM Tuning:ꢀUsingꢀtheꢀ“AFMꢀTuningꢀAssistant”ꢀfindꢀtheꢀPL560ꢁ3xꢀinꢀtheꢀL2Xꢀworksheet.ꢀꢀEnterꢀtheꢀ
CinternalꢀvalueꢀfoundꢀnextꢀtoꢀitꢀintoꢀcellꢀB21.ꢀꢀInꢀcellꢀB24ꢀenterꢀtheꢀclosestꢀstandardꢀinductorꢀvalueꢀ(seeꢀCoilCraftꢀ
0603CSꢀseriesꢀforꢀexample)ꢀtoꢀachieveꢀtheꢀclosestꢀpeakꢀfrequencyꢀtoꢀ60ꢀMHz.ꢀꢀꢀRepeatꢀtheꢀsameꢀprocedureꢀforꢀ
L4Xꢀatꢀ120ꢀMHz.ꢀꢀꢀ
Results: L2X = 180 nH, L4X = 82 nH.ꢀ
ꢀ
320 MHz AFM tuning:ꢀRepeatꢀtheꢀpreviousꢀprocedureꢀforꢀL2Xꢀatꢀ120ꢀMHzꢀandꢀL4Xꢀatꢀ320ꢀMHz.ꢀ
Results: L2X = 24 nH, L4X = 10 nH.ꢀ
ꢀ
Proceedꢀandꢀassembleꢀtheꢀtestꢀunits.ꢀ
ꢀ
Measuring 120 MHz L2X: ConnectꢀtheꢀRFꢀgeneratorꢀandꢀscopeꢀprobeꢀasꢀshownꢀinꢀFigureꢀ6,ꢀabove.ꢀꢀꢀWhileꢀ
powerꢀisꢀappliedꢀtoꢀtheꢀPCB,ꢀsetꢀtheꢀgeneratorꢀoutputꢀtoꢀ+12ꢀdBmꢀandꢀtheꢀfrequencyꢀtoꢀ30ꢀMHz.ꢀꢀSinceꢀthisꢀisꢀtheꢀ
2xꢀport,ꢀtheꢀscopeꢀwillꢀshowꢀ60ꢀMHzꢀwithꢀ~ꢀ3Vꢀpkꢁpkꢀamplitude.ꢀꢀVaryꢀtheꢀgeneratorꢀaboveꢀandꢀbelowꢀ30ꢀMHzꢀuntilꢀ
47745ꢀFremontꢀBlvd.,ꢀFremont,ꢀCAꢀ94538ꢀꢀTELꢀ(510)ꢀ492ꢁ0990,ꢀFAXꢀ(510)ꢀ492ꢁ0991ꢀꢀꢀ www.phaselink.comꢀꢀꢀꢀꢀRev.:02ꢁ09ꢁ07ꢀꢀPageꢀ7ꢀꢀ
PLL [ PHASELINK CORPORATION ]
