Electronic Circuits Laboratory EE462G Lab #2InstrumentationSlide 3Slide 4Slide 5Acquisition ModesSlide 7Screen ScalingSlide 9Collector Supply SweepSlide 11Step GeneratorSlide 13Transfer CharacteristicsDiodeIdeal Diode Modeln-Channel MOSFETFET OperationCutoff RegionTriode RegionSaturation RegionNMOS Transfer CharacteristicsSlide 23Slide 24Find K from Curve TraceFind K from Curve Trace (LS)Plot Diode TCCurve fit Parameter EstimationSlide 29Slide 30Slide 31Slide 32Best-fit-Curve with Diode DataPlot MOSFET TCCurve Fit Parameter EstimationSlide 36Slide 37Slide 38Plot of Best-Fit with Error SurfaceElectronic Circuits LaboratoryEE462GLab #2Characterizing Nonlinear Elements, Curve Tracers, Transfer Characteristics, Curve Fit Programs.InstrumentationThis lab requires:Tektronix’s Curve Tracer 370B.For the data sheet you must save the displayed waveform to a floppy disk and paste (if BMP) or load and plot (if CSV) using excel or Matlab.Make special note of the curve dynamics. Make sure the scale allows the critical curve dynamics to be clearly seen over a useful range of interest. Poor parameter estimates result for mostly flat (or vertical) curve portions.http://www.tek.com/site/ps/0,,76-10757-SPECS_EN,00.htmlInstrumentationTektronix’s Curve Tracer 370B operation. For diode, no connection is made to the step generator.Figure taken from Tektronix User Manual 370B Programmable Curve Tracer070-A838-50 http://www.tek.com/site/ps/0,,76-10757-SPECS_EN,00.htmlInstrumentationExample displays for diode with different collector settingsAC collector sweepPositive DC collector sweep0,0 0,0InstrumentationExample displays for FET drain characteristics with different gate-source voltage steps and horizontal and vertical scales.Offset 1.492 VStep .2 VStep Number 7Offset 1.5 VStep .5 VStep Number 7Acquisition ModesTaken from Tektronix User Manual 370B Programmable Curve Tracer070-A838-50 http://www.tek.com/site/ps/0,,76-10757-SPECS_EN,00.htmlAcquisition ModesTaken from Tektronix User Manual 370B Programmable Curve Tracer070-A838-50 http://www.tek.com/site/ps/0,,76-10757-SPECS_EN,00.htmlScreen ScalingTaken from Tektronix User Manual 370B Programmable Curve Tracer070-A838-50 http://www.tek.com/site/ps/0,,76-10757-SPECS_EN,00.htmlScreen ScalingTaken from Tektronix User Manual 370B Programmable Curve Tracer070-A838-50 http://www.tek.com/site/ps/0,,76-10757-SPECS_EN,00.htmlCollector Supply SweepTaken from Tektronix User Manual 370B Programmable Curve Tracer070-A838-50 http://www.tek.com/site/ps/0,,76-10757-SPECS_EN,00.htmlCollector Supply SweepTaken from Tektronix User Manual 370B Programmable Curve Tracer070-A838-50 http://www.tek.com/site/ps/0,,76-10757-SPECS_EN,00.htmlStep GeneratorTaken from Tektronix User Manual 370B Programmable Curve Tracer070-A838-50 http://www.tek.com/site/ps/0,,76-10757-SPECS_EN,00.htmlStep GeneratorTaken from Tektronix User Manual 370B Programmable Curve Tracer070-A838-50 http://www.tek.com/site/ps/0,,76-10757-SPECS_EN,00.htmlTransfer CharacteristicsA relation describing the amplitude input-output relationship of a device.A sufficient characterization in most engineering problems for instantaneous systems (present output does not depend on future or previous values). These systems are sometimes referred to as memoryless, and are typical of systems with no energy storage elements. Transfer CharacteristicsDiode modelA semiconductor device with direction dependent current flow. Volt-Ampere Characterization of a diode.Diode http://www.wodonga.tafe.edu.au/eemo/ne178/tut2_1.htmId Anode Cathode+ Vd -The band on the component usually denotes the cathode terminalForward BiasReverse BiasIdeal approximation:Short CircuitIdeal approximation:Open CircuitKneeVDIDVZIdeal Diode ModelDiode junction acts as a short circuit for forward bias (VD > 0 (anode positive)).Diode junction acts as an open circuit for reverse bias (VD < 0 (anode negative)).Near-Ideal Diode ModelAdd a 0.7 voltage source for the forward offset voltage in series ideal diode with same polarity as the forward bias.Ideal Diode Model Anode Cathode+ Vd = 0 -Id Diode On Anode Cathode+ Vd -Id 0.7 VAnode Cathode- Vd +Id = 0 Diode Offn-Channel MOSFETA Metal-Oxide-Semiconductor field-effect transistor (MOSFET) is presented for charge flowing in an n-channel:+VGS_+VDS_DGSBB – Body or SubstrateD – DrainG – GateS – SourceFor many applications the body is connected to the source and thus most FETs are packaged that way.nnpIDGDSFET OperationThe current flow between the drain and the source can be controlled by applying a positive gate voltage:Three Regions of Operation:Cutoff region (VGS  Vtr)Triode region (VDS  VGS - Vtr )Saturation (VGS - Vtr  VDS )nnp+VGS_+VDS_------VGSIDCutoff RegionIn this region (VGS  Vtr) the gate voltage is less than the threshold voltage and virtually no current flows through the reversed biased PN interface between the drain and body.Typical values for Vtr (or Vto) range from 1 to several volts. Cutoff region: ID=0nnp+VGS_+VDS_ID++++++++++--------------Triode RegionIn this region (VGS > Vtr and VDS  VGS - Vtr ) the gate voltage exceeds the threshold voltage and pulls negative charges toward the gate. This results is an n-Channel whose width controls the current flow ID between the drain and source.Triode Region: (VDS  VGS - Vtr )nnp+VGS_+VDS_------VGSID 222DSDStrGSDVVVVKPLWI  )(where:product of surface mobility of channel electrons n and gate capacitance per unit area Cox in units of amps per volts squared,W is the channel width, andL is channel length.oxnCKPSaturation RegionIn this region (VGS > Vtr and VGS - Vtr  VDS ) the drain-source voltage exceeds the excess gate voltage and pulls negative charges toward the drain and reduces the channel area at the drain. This limits the current making it more insensitive/independent to changes in VDS.Saturation: VGS - Vtr  VDS +VGS_+VDS_nnp-----ID22)(trGSDVVKPLWI 2)(trGSDVVKI The material parameters can be combined into one constant:At the point of Saturation, for a given VGS , the following relation holds:2DSDKVI NMOS Transfer CharacteristicsThe relations between ID and VDS for the operational regions of the NMOS transistor can be used to generate its transfer characteristic. These can be conveniently coded in a Matlab functionfunction ids = nmos(vds,vgs,KP,W,L,vto)% This function generates