SUMMARY Inthispaper,isshownanapproachtorealizeleapfrogstructuresobtainedfromproto-typepassiveRLCladderfiltersusingcurrentdifferencingbufferedamplifiers(CDBA)asactiveelements.TheuseoftheCDBA’sprovidesadvantagesthattherealizationprocedureissimplifiedandthenumberofactivecomponentsrequiredisreduced. Theapproachisquitesuitablefortherealizationofband-passladderfilters,whichgenerallyre-quiresacomplicatedstructuretosimulateLCseriesand/orpar-allelresonantbranchesbytheconventionalopamp-basedleapfrogfilters. AsimplecircuitconfigurationoftheCDBAsuitableforhighfrequencyandlowpowersupplyvoltageapplicationsisalsopresented. As design examples, a fifth-order Butterworth low-passladderfilterandasixth-orderChebyshevbandpassladderfilteraredesigned. Theeffectivenessandthecorrectnessoftheproposedapproachandthecharacteristicsoftheproposedfiltersareverifiedandexaminedthroughcomputersimulation. key words: current differencing buffered amplifier, CDBA, low-voltage circuit, leapfrog filter, active filter 1. IntroductionRecent advanced technologies of integrated circuitsmakedevicesinanICsosmallthattheinternalelectricfieldmaybecomeextremelyhigh,thusthepowersup-plyvoltageofcircuitsmustberestrictedtoalowvalue.Inaddition,withthepopularizationofportableequip-ments, single battery operation of equipments is nowmostessential. Highfrequencyoperationofcircuitsisalso a key word today. In these respects, realizationoflow-voltagehigh-frequencyactivefiltersisoneofthemost attractive and important issues in many signalprocessingfields.ActiveRCfilterisoneofthecandidatesoffiltersthatmayhavepossibilitiesofintegrationandhighfre-quencyandlowvoltageoperation. Leapfrogstructurethat simulates doubly terminated LC filters has beenhighly appreciatedsince itinheritsthelow sensitivitynaturesoftheproto-typeLCfilters[1]. ActiveRCfil-
[1]
Akira Hyogo,et al.
A synthesis of a novel current-mode operational amplifier
,
1996
.
[2]
J. A. Svoboda.
Transfer function synthesis using current conveyors
,
1994
.
[3]
Ali Toker,et al.
Current-mode continuous-time fully-integrated universal filter using CDBAs
,
1999
.
[4]
Serdar Ozoguz,et al.
A new versatile building block: current differencing buffered amplifier suitable for analog signal-processing filters
,
1999
.
[5]
Cevdet Acar,et al.
nth-order current transfer function synthesis using current differencing buffered amplifier: signal-flow graph approach
,
2000
.
[6]
K. Smith,et al.
A second-generation current conveyor and its applications
,
1970,
IEEE Transactions on Circuit Theory.