CMOS NAND Gate Circuit Diagram | Working Principle

Fig. 3.3 shows CMOS NAND Gate Circuit Diagram 2-input NAND gate. It consists of two P-channel MOSFETs, Q1 and Q2, connected in parallel and two N-channel ... Skiptocontent Home»DigitalIntegratedCircuits»CMOSNANDGateCircuitDiagram CMOSNANDGateCircuitDiagram: Fig.3.3showsCMOSNANDGateCircuitDiagram2-inputNANDgate.ItconsistsoftwoP-channelMOSFETs,Q1andQ2,connectedinparallelandtwoN-channelMOSFETs,Q3andQ4connectedinseries. P-channelMOSFETisONwhenitsgatevoltageisnegativewithrespecttoitssourcewhereasN-channelMOSFETisONwhenitsgatevoltageispositivewithrespecttoitssource Fig.3.3(a)showstheequivalentswitchingcircuitwhenbothinputsarelow.Here,thegatesofbothP-channelMOSFETsarenegativewithrespecttotheirsources,sincethesourcesareconnectedto+VDD.Thus,Q1andQ2arebothON.Sincethegate–to–sourcevoltagesofQ3andQ4(N-channelMOSFETs)areboth0V,thoseMOSFETsareOFF.Theoutputisthereforeconnectedto+VDD (HIGH)throughQ1 andQ2andisdisconnectedfromground,asshownintheFig.3.3(b). Fig.3.3(c)showstheequivalentswitchingcircuitwhenA=0andB=+VDD.Inthiscase,Q1isonbecauseVGS1 =−VDDandQ4isONbecauseVGS4 =+VDD.MOSFETsQ2andQ3areoffbecausetheirgate-to-sourcevoltagesare0V.SinceQ1isONandQ3isOFF,theoutputisconnectedto+VDDanditisdisconnectedfromground.WhenA=+VDDandB=0V,thesituationissimilar(notshown);theoutputisconnectedto+VDDthroughQ2anditisdisconnectedfromgroundbecauseQ4isOFF.Finally,whenbothinputsarehigh(A=B=+VDD),MOSFETsQ1andQ2arebothOFFandQ3andQ4arebothON.Thus,theoutputisconnectedtothegroundthroughQ3 andQ4anditisdisconnectedfrom+VDD. TheTable3.2summarizestheoperation of2-inputCMOSInverterNANDgate. Postnavigation ←PreviousPostNextPost→ RelatedPosts: Search MainCategories Circuits ElectricalDrives ElectricalMachines ElectronicCommunication ElectronicDevices ElectronicInstrumentation HighVoltage IntegratedCircuits Microprocessors ModernPowerSystem NetworkAnalysis PowerSystem PowerSystemProtection ElectricalandElectronicsImportantQuestionsandAnswers Comparisons RecentArticle CurrentComponentsinPNJunctionDiode WhatisanIdealDiode–WorkinganditsV-ICharacteristics DifferencebetweenZenerBreakdownandAvalancheBreakdown BreakdownVoltageofPNJunctionDiode DiodeFailureModesandCauses ExplainSteadyStateConditionsinSemiconductor MetalSemiconductorJunctions ZerobiasPNjunction SpaceChargeRegionataJunction ChargeNeutralityEquationinSemiconductor EquilibriumConditionsinSemiconductorPhysics BasicStructureofPNJunctioninSemiconductor WhatisHallEffectinSemiconductor? ContinuityEquationinSemiconductor CarrierLifetimeinSemiconductor ToReceiveUpdates