Chapter 14 BJT Models - University Of Washington
hspice.book : hspice.ch141 Thu Jul 23 19:10:43 1998Chapter 14BJT ModelsIThe bipolar-junction transistor (BJT) model in HSPICE is an adaptation of theintegral charge control model of Gummel and Poon.The HSPICE model extends the original Gummel-Poon model to include severaleffects at high bias levels. This model automatically simplifies to the Ebers-Mollmodel when certain parameters (VAF, VAR, IKF, and IKR) are not specified.This chapter covers the following topics: Using the BJT Model Using the BJT Element Understanding the BJT Model Statement Using the BJT Models (NPN and PNP) Understanding BJT Capacitances Modeling Various Types of Noise Using the BJT Quasi-Saturation Model Using Temperature Compensation Equations Converting National Semiconductor ModelsStar-Hspice Manual, Release 1998.214-1
hspice.book : hspice.ch142 Thu Jul 23 19:10:43 1998Using the BJT ModelBJT ModelsUsing the BJT ModelThe BJT model is used to develop BiCMOS, TTL, and ECL circuits. ForBiCMOS devices, use the high current Beta degradation parameters, IKF andIKR, to modify high injection effects. The model parameter SUBS facilitates themodeling of both vertical and lateral geometrics.Model SelectionTo select a BJT device, use a BJT element and model statement. The elementstatement references the model statement by the reference model name. Thereference name is given as MOD1 in the following example. In this case an NPNmodel type is used to describe an NPN transistor.ExampleQ3 3 2 5 MOD1 parameters .MODEL MOD1 NPN parameters Parameters can be specified in both element and model statements. The elementparameter always overrides the model parameter when a parameter is specifiedas both. The model statement specifies the type of BJT, for example, NPN orPNP.14-2Star-Hspice Manual, Release 1998.2
hspice.book : hspice.ch143 Thu Jul 23 19:10:43 1998BJT ModelsUsing the BJT ModelControl OptionsControl options affecting the BJT model are: DCAP, GRAMP, GMIN, andGMINDC. DCAP selects the equation which determines the BJT capacitances.GRAMP, GMIN, and GMINDC place a conductance in parallel with both thebase-emitter and base-collector pn junctions. DCCAP invokes capacitancecalculations in DC analysis.Table 14-1: BJT OptionscapacitanceDCAP, DCCAPconductanceGMIN, GMINDC, GRAMPOverride global depletion capacitance equation selection that uses the .OPTIONDCAP val statement in a BJT model by including DCAP val in theBJT’s .MODEL statement.ConvergenceAdding a base, collector, and emitter resistance to the BJT model improves itsconvergence. The resistors limit the current in the device so that the forwardbiased pn junctions are not overdriven.Star-Hspice Manual, Release 1998.214-3
hspice.book : hspice.ch144 Thu Jul 23 19:10:43 1998Using the BJT ElementBJT ModelsUsing the BJT ElementThe BJT element parameters specify the connectivity of the BJT, normalizedgeometric specifications, initialization, and temperature parameters.Table 14-2: BJT Element ParametersTypeParametersnetlistQxxx, mname, nb, nc, ne, nsgeometricAREA, AREAB, AREAC, MinitializationIC (VBE, VCE), OFFtemperatureDTEMPGeneral formQxxx nc nb ne ns mname aval OFF IC vbeval,vceval M val DTEMP val orQxxx nc nb ne ns mname AREA val AREAB val AREAC val OFF VBE val VCE val M val DTEMP val 14-4QxxxBJT element name. Must begin with a “Q”, which can befollowed by up to 15 alphanumeric characters.nccollector terminal node namenbbase terminal node nameneemitter terminal node namenssubstrate terminal node name, optional. Can be set in themodel with BULK Node name.mnamemodel name referenceavalvalue for AREAStar-Hspice Manual, Release 1998.2
hspice.book : hspice.ch145 Thu Jul 23 19:10:43 1998BJT ModelsUsing the BJT ElementOFFsets initial condition to OFF for this element in DC analysis.Default ON.IC vbeval,initial internal base to emitter voltage (vbeval) or initial internalcollector tovcevalemitter voltage (vceval). Overridden by the .IC statement.Mmultiplier factor to simulate multiple BJTs. All currents,capacitances, and resistances are affected by M.DTEMPthe difference between element and circuit temperature(default 0.0)AREAemitter area multiplying factor that affects resistors,capacitors, and currents (default 1.0)AREABbase area multiplying factor that affects resistors, capacitors,and currents (default AREA)AREACcollector area multiplying factor that affects resistors,capacitors, and currents (default AREA)ExamplesQ100 CX BX EX QPNP AREA 1.5 AREAB 2.5 AREAC 3.0Q23 10 24 13 QMOD IC 0.6,5.0Q50A 11 265 4 20 MOD1ScalingScaling is controlled by the element parameters AREA, AREAB, AREAC, andM. The AREA parameter, the normalized emitter area, divides all resistors andmultiplies all currents and capacitors. AREAB and AREAC scale the size of thebase area and collector area. Either AREAB or AREAC is used for scaling,depending on whether vertical or lateral geometry is selected (using the SUBSmodel parameter). For vertical geometry, AREAB is the scaling factor for IBC,ISC, and CJC. For lateral geometry, AREAC is the scaling factor. The scalingfactor is AREA for all other parameters.Star-Hspice Manual, Release 1998.214-5
hspice.book : hspice.ch146 Thu Jul 23 19:10:43 1998Using the BJT ElementBJT ModelsThe scaling of the DC model parameters (IBE, IS, ISE, IKF, IKR, and IRB) forboth vertical and lateral BJT transistors, is determined by the following formula:Ieff AREA M Iwhere I is either IBE, IS, ISE, IKF, IKR, or IRB.For both the vertical and lateral the resistor model parameters, RB, RBM, RE,and RC are scaled by the following equation.RReff ------------------------AREA Mwhere R is either RB, RBM, RE, or RC.BJT Current ConventionThe direction of current flow through the BJT is assumed for example purposesin Figure 13-1. Use either I(Q1) or I1(Q1) syntax to print the collector current.I2(Q1) refers to the base current, I3(Q1) refers to the emitter current, and I4(Q1)refers to the substrate current.nb(base node)I2(Q1)nc(collector node)I1(Q1)ns(substrate node)I4(Q1)ne(emitter node)I3(Q1)Figure 13-1 – BJT Current Convention14-6Star-Hspice Manual, Release 1998.2
hspice.book : hspice.ch147 Thu Jul 23 19:10:43 1998BJT ModelsUsing the BJT ElementBJT Equivalent CircuitsHSPICE uses four equivalent circuits in the analysis of BJTs: DC, transient, AC,and AC noise circuits. The components of these circuits form the basis for allelement and model equations. Since these circuits represent the entire BJT inHSPICE, every effort has been made to demonstrate the relationship between theequivalent circuit and the element/model parameters.The fundamental components in the equivalent circuit are the base current (ib)and the collector current (ic). For noise and AC analyses, the actual ib and iccurrents are not used. The partial derivatives of ib and ic with respect to theterminal voltages vbe and vbc are used instead. The names for these partialderivatives are:Reverse Base Conductance ibgµ ----------- vbcvbe const.Forward Base Conductance ibgπ ----------- vbevbc const.Collector Conductance icg o ---------- vcevbe const. ic – ----------- vbcStar-Hspice Manual, Release 1998.2vbe const.14-7
hspice.book : hspice.ch148 Thu Jul 23 19:10:43 1998Using the BJT ElementBJT ModelsTransconductance icgm ----------- vbevce cons ic ic ------------ ----------- vbe vbc ic ------------ – g o vbeThe ib and ic equations account for all DC effects of the SubstrateCCSPreCBEPEmitterFigure 13-1: Lateral Transistor, BJT Transient Analysis14-8Star-Hspice Manual, Release 1998.2
hspice.book : hspice.ch149 Thu Jul 23 19:10:43 1998BJT ModelsUsing the BJT eSubstratecbeibereCBEPEmitterFigure 13-2: Vertical Transistor, BJT Transient AnalysisStar-Hspice Manual, Release 1998.214-9
hspice.book : hspice.ch1410 Thu Jul 23 19:10:43 1998Using the BJT ElementBJT ModelsCollectorCBCPcbcxgbccbcrbBasegm e 13-3: Lateral Transistor, BJT AC Analysis14-10Star-Hspice Manual, Release 1998.2
hspice.book : hspice.ch1411 Thu Jul 23 19:10:43 1998BJT ModelsUsing the BJT ElementCollectorCBCPcbcxBaseCCSPrcgbccbcrbgscgm vbecscgoSubstrategbecbereCBEPEmitterFigure 13-4: Vertical Transistor, BJT AC AnalysisStar-Hspice Manual, Release 1998.214-11
hspice.book : hspice.ch1412 Thu Jul 23 19:10:43 1998Using the BJT ElementBJT ModelsCollectorCBCPcbcxgbccbcgm vberbBaseInrcrcgoIncInrbcbe gbe InbgbscbsSubstrateCCSPreInreCBEPEmitterFigure 13-5: Lateral Transistor, BJT AC Noise Analysis14-12Star-Hspice Manual, Release 1998.2
hspice.book : hspice.ch1413 Thu Jul 23 19:10:43 1998BJT ModelsUsing the BJT ElementCollectorCBCPcbcxBasegbccbcgscgm vberbCCSPInrcrcgocscIncSubstrateInrbcbe gbe InbreInreCBEPEmitterFigure 13-6: Vertical Transistor, BJT AC Noise AnalysisTable 13-2: Equation Variable NamesVariableDefinitionscbcinternal base to collector capacitancecbcxexternal base to collector capacitancecbeinternal base to emitter capacitancecscsubstrate to collector capacitance (vertical transistor only)cbsbase to substrate capacitance (lateral transistor only)ffrequencygbcreverse base conductanceStar-Hspice Manual, Release 1998.214-13
hspice.book : hspice.ch1414 Thu Jul 23 19:10:43 1998Using the BJT ElementBJT ModelsTable 13-2: Equation Variable Names14-14VariableDefinitionsgbeforward base conductancegmtransconductancegscsubstrate to collector conductance (vertical transistor only)gocollector conductancegbsbase to substrate conductance (lateral transistor only)ibexternal base terminal currentibcDC current base to collectoribeDC current base to emittericexternal collector terminal currenticeDC current collector to emitterinbbase current equivalent noiseinccollector current equivalent noiseinrbbase resistor current equivalent noiseinrccollector resistor equivalent noiseinreemitter resistor current equivalent noiseibsDC current base to substrate (lateral transistor only)iscDC current substrate to collector (vertical transistor only)qbnormalized base chargerbbase resistancerbbshort-circuit base resistancevbsinternal base substrate voltagevscinternal substrate collector voltageStar-Hspice Manual, Release 1998.2
hspice.book : hspice.ch1415 Thu Jul 23 19:10:43 1998BJT ModelsUsing the BJT ElementTable 13-3: Equation ConstantsQuantitiesDefinitionsk1.38062e-23 (Boltzmann’s constant)q1.60212e-19 (electron charge)ttemperature in Kelvin tt - tnomtnomtnom 273.15 TNOM in Kelvinvt(t)k t/qvt(tmon)k tnom/qStar-Hspice Manual, Release 1998.214-15
hspice.book : hspice.ch1416 Thu Jul 23 19:10:43 1998Understanding the BJT Model StatementBJT ModelsUnderstanding the BJT Model StatementGeneral form.MODEL mname NPN ( pname1 val1 . ) or.MODEL mname PNP pname1 val1 .mnamemodel name. Elements refer to the model by this name.NPNidentifies an NPN transistor modelpname1Each BJT model can include several model parameters.PNPidentifies a PNP transistor modelExample.MODEL t2n2222a NPN ISS 0.XTF 1.NS 1.00000 CJS 0.VJS 0.50000PTF 0. MJS 0.EG 1.10000AF 1. ITF 0.50000VTF 1.00000F 153.40622 BR 40.00000IS 1.6339e-14 VAF 103.40529 VAR 17.77498IKF 1.00000IS 4.6956e-15 NE 1.31919IKR 1.00000ISC 3.6856e-13 NC 1.10024IRB 4.3646e-05 NF 1.00531 NR 1.00688RBM 1.0000e-02 RB 71.82988 RC 0.42753RE 3.0503e-03 MJE 0.32339 MJC 0.34700VJE 0.67373VJC 0.47372 TF 9.693e-10 TR 380.00e-9CJE 2.6734e-11 CJC 1.4040e-11 FC 0.95000XCJC 0.9451814-16Star-Hspice Manual, Release 1998.2
hspice.book : hspice.ch1417 Thu Jul 23 19:10:43 1998BJT ModelsUnderstanding the BJT Model StatementBJT Basic Model ParametersTo permit the use of model parameters from earlier versions of HSPICE, manyof the model parameters have aliases, which are included in the model parameterlist in “BJT Basic DC Model Parameters” on page 14-19. The new name isalways used on printouts, even if an alias is used in the model statement.BJT model parameters are divided into several groups. The first group of DCmodel parameters includes the most basic Ebers-Moll parameters. This model iseffective for modeling low-frequency large-signal characteristics.Low current Beta degradation effect parameters ISC, ISE, NC, and NE aid inmodeling the drop in the observed Beta, caused by the following mechanisms: recombination of carriers in the emitter-base space charge layer recombination of carriers at the surface formation of emitter-base channelsLow base and emitter dopant concentrations, found in some BIMOS typetechnologies, typically use the high current Beta degradation parameters, IKFand IKR.Use the base-width modulation parameters, that is, early effect parameters VAFand VAR, to model high-gain, narrow-base devices. The model calculates theslope of the I-V curve for the model in the active region with VAF and VAR. IfVAF and VAR are not specified, the slope in the active region is zero.The parasitic resistor parameters RE, RB, and RC are the most frequently usedsecond-order parameters since they replace external resistors. This simplifies theinput netlist file. All the resistances are functions of the BJT multiplier M value.The resistances are divided by M to simulate parallel resistances. The baseresistance is also a function of base current, as is often the case in narrow-basetechnologies.Transient model parameters for BJTs are composed of two groups: junctioncapacitor parameters and transit time parameters. The base-emitter junction ismodeled by CJE, VJE, and MJE. The base-collector junction capacitance ismodeled by CJC, VJC, and MJC. The collector-substrate junction capacitance ismodeled by CJS, VJS, and MJS.Star-Hspice Manual, Release 1998.214-17
hspice.book : hspice.ch1418 Thu Jul 23 19:10:43 1998Understanding the BJT Model StatementBJT ModelsTF is the forward transit time for base charge storage. TF can be modified toaccount for bias, current, and phase, by XTF, VTF, ITF, and PTF. The basecharge storage reverse transit time is set by TR. There are several sets oftemperature equations for the BJT model parameters that you can select bysetting TLEV and TLEVC.Table 13-4: – BJT Model ParametersDCBF, BR, IBC, IBE, IS, ISS, NF, NR, NS, VAF, VARbeta degradationISC, ISE, NC, NE, IKF, IKRgeometricSUBS, BULKresistorRB, RBM, RE, RC, IRBjunction JCparasitic capacitanceCBCP, CBEP, CCSPtransit timeITF, PTF, TF, VT, VTF, XTFnoiseKF, AF14-18Star-Hspice Manual, Release 1998.2
hspice.book : hspice.ch1419 Thu Jul 23 19:10:43 1998BJT ModelsUnderstanding the BJT Model StatementBJT Basic DC Model ParametersName(Alias)DefaultDescriptionBF (BFM)100.0ideal maximum forward BetaBR (BRM)1.0ideal maximum reverse BetaBULK(NSUB)0.0sets the bulk node to a global node name. A substrateterminal node name (ns) in the element statementoverrides BULK.0.0reverse saturation current between base and collector.If both IBE and IBC are specified, HSPICE uses themin place of IS to calculate DC current and conductance,otherwise IS is used.IBCUnitsampIBCeff IBC AREAB MAREAC replaces AREAB, depending on vertical orlateral geometry.EXPLIamp1e15current explosion model parameter. The PN junctioncharacteristics above the explosion current area linear,with the slope at the explosion point. This speeds upsimulation and improves convergence.EXPLIeff EXPLI AREAeffIBEamp0.0reverse saturation current between base and emitter. Ifboth IBE and IBC are specified, HSPICE uses them inplace of IS to calculate DC current and conductance,otherwise IS is used.IBEeff IBE AREA MStar-Hspice Manual, Release 1998.214-19
hspice.book : hspice.ch1420 Thu Jul 23 19:10:43 1998Understanding the BJT Model StatementBJT 16transport saturation current. If both IBE and IBC arespecified, HSPICE uses them in place of IS to calculateDC current and conductance, otherwise IS is used.ISeff IS AREA MISSamp0.0reverse saturation current bulk-to-collector or bulk-tobase, depending on vertical or lateral geometryselectionSSeff ISS AREA MLEVEL1.0model selectorNF1.0forward current emission coefficientNR1.0reverse current emission coefficientNS1.0substrate current emission coefficientSUBSsubstrate connection selector: 1 for vertical geometry, -1 for lateral geometrydefault 1 for NPN, default -1 for PNPUPDATE14-200UPDATE 1 selects alternate base charge equationStar-Hspice Manual, Release 1998.2
hspice.book : hspice.ch1421 Thu Jul 23 19:10:43 1998BJT ModelsUnderstanding the BJT Model StatementLow Current Beta Degradation Effect ParametersISC (C4, JLC)amp0.0base-collector leakage saturation current. If ISC isgreater than 1e-4, then:ISC IS ISCotherwise:ISCeff ISC AREAB MAREAC replaces AREAB, depending on vertical orlateral geometry.ISE (C2, JLE)amp0.0base-emitter leakage saturation current. If ISE isgreater than1e-4, then:ISE IS ISEotherwise:ISEeff ISE AREA MNC (NLC)2.0base-collector leakage emission coefficientNE (NLE)1.5base-emitter leakage emission coefficientStar-Hspice Manual, Release 1998.214-21
hspice.book : hspice.ch1422 Thu Jul 23 19:10:43 1998Understanding the BJT Model StatementBJT ModelsBase Width Modulation ParametersVAF (VA, VBF)V0.0forward early voltage. Use zero to indicate aninfinite value.VAR (VB,VRB, BV)V0.0reverse early voltage. Use zero to indicate aninfinite value.High Current Beta Degradation Effect ParametersIKF IK,JBF)amp0.0corner for forward Beta high current roll-off. Use zero toindicate an infinite value.IKFeff IKF AREA MIKR (JBR)amp0.0corner for reverse Beta high current roll-off. Use zero toindicate an infinite valueIKReff IKR AREA MNKF14-220.5exponent for high current Beta roll-offStar-Hspice Manual, Release 1998.2
hspice.book : hspice.ch1423 Thu Jul 23 19:10:43 1998BJT ModelsUnderstanding the BJT Model StatementParasitic Resistance ParametersIRB (JRB,IOB)amp0.0base current, where base resistance falls half-way toRBM. Use zero to indicate an infinite value.IRBeff IRB AREA MRBohm0.0base resistanceRBeff RB / (AREA M)RBMohmRBminimum high current base resistanceRBMeff RBM / (AREA M)REohm0.0emitter resistanceREeff RE / (AREA M)RCohm0.0collector resistanceRCeff RC / (AREA M)Junction Capacitor ParametersCJCF0.0base-collector zero-bias depletion capacitanceVertical: CJCeff CJC AREAB MLateral: CJCeff CJC AREAC MStar-Hspice Manual, Release 1998.214-23
hspice.book : hspice.ch1424 Thu Jul 23 19:10:43 1998Understanding the BJT Model StatementCJEF0.0BJT Modelsbase-emitter zero-bias depletion capacitance(vertical and lateral):CJEeff CJE AREA MCJS(CCS,CSUB)F0.0zero-bias collector substrate capacitanceVertical: CJSeff CJS AREAC MLateral: CJSeff CJS AREAB MFC0.5coefficient for forward bias depletion capacitanceformula for DCAP 1DCAP Default 2 and FC is ignoredMJC(MC)0.33base-collector junction exponent (grading factor)MJE(ME)0.33base-emitter junction exponent (grading factor)MJS(ESUB)0.5substrate junction exponent (grading factor)VJC(PC)V0.75base-collector built-in potentialVJE (PE)V0.75base-emitter built-in potentialVJS(PSUB)V0.75substrate junction built in potential1.0internal base fraction of base-collector depletioncapacitanceXCJC(CDIS)14-24Star-Hspice Manual, Release 1998.2
hspice.book : hspice.ch1425 Thu Jul 23 19:10:43 1998BJT ModelsUnderstanding the BJT Model StatementParasitic CapacitancesCBCPF0.0external base-collector constant capacitanceCBCPeff CBCP AREA MCBEPF0.0external base-emitter constant capacitanceCBEPeff CBEP AREA MCCSPF0.0external collector substrate constant capacitance(vertical) or base substrate (lateral)CCSPeff CCSP AREA MTransit Time ParametersITF (JTF)amp0.0TF high-current parameterITFeff ITF AREA MPTF0.0frequency multiplier to determine excess phaseTFs0.0base forward transit timeTRs0.0base reverse transit timeVTFV0.0TF base-collector voltage dependen
BJT Models Using the BJT Model Star-Hspice Manual, Release 1998.2 14-3 Control Options Control options affecting the BJT model are: DCAP, GRAMP, GMIN, and GMINDC. DCAP selects the equation which determines the BJT capacitances. GRAMP, GMIN, and GMINDC place a conductance in parallel with both the base-emitter and base-collector pn junctions.
Standard SPICE models: Diode, BJT, MOSFET, JFET and MESFET CMC and other models: BJT –HICUM/L2/L0 MOSFET –EKV2.6 Qucs-S/Xyce Standard SPICE models: Diode, BJT, MOSFET, JFET and MESFET CMC and other models: BJT –VBIC 1.3, FBH HBT_X, HICUML0/L2, MEXTRAM. MOSFET –BSIM3, BSIM4, BSIM6, BSIM_SOI, BSIM_CMG, MVS, PSP Verilog-A ADMS generated models
Frequency Response of BJT 1) Objectives: To study the frequency response and bandwidth of the common emitter CE-BJT, the common collector CC-BJT, and the common base CB-BJT amplifiers. 2) Introduction: Most amplifiers have relatively
Debapratim Ghosh An Introduction to Basic Electronics 11/25. Device Physics The Diode The Transistor Signals Basic Circuits Basics of the BJT BJT Working Principle Revision Quiz TheBipolarJunctionTransistor(BJT) The BJT has two p-n junctions. Since the BJT has two junctions, it can be a p-n-p or an n-p-n device.
Part One: Heir of Ash Chapter 1 Chapter 2 Chapter 3 Chapter 4 Chapter 5 Chapter 6 Chapter 7 Chapter 8 Chapter 9 Chapter 10 Chapter 11 Chapter 12 Chapter 13 Chapter 14 Chapter 15 Chapter 16 Chapter 17 Chapter 18 Chapter 19 Chapter 20 Chapter 21 Chapter 22 Chapter 23 Chapter 24 Chapter 25 Chapter 26 Chapter 27 Chapter 28 Chapter 29 Chapter 30 .
TO KILL A MOCKINGBIRD. Contents Dedication Epigraph Part One Chapter 1 Chapter 2 Chapter 3 Chapter 4 Chapter 5 Chapter 6 Chapter 7 Chapter 8 Chapter 9 Chapter 10 Chapter 11 Part Two Chapter 12 Chapter 13 Chapter 14 Chapter 15 Chapter 16 Chapter 17 Chapter 18. Chapter 19 Chapter 20 Chapter 21 Chapter 22 Chapter 23 Chapter 24 Chapter 25 Chapter 26
Lecture 7. Bipolar Junction Transistor (BJT) Figure 7.9: Large signal equivalent model of the NPN BJT operating in the forward active mode. Figure 7.10: Large signal equivalent model of the NPN BJT operating in the reverse active mode. collector. — βR is in the range of
BJT amplifiers of various configurations. While there is a lot more detail we can discuss in terms of BJTs and their large signal behavior, we will stop with the discussion of BJT amplifiers and continue next lecture with MOSFETs which we will focus on for the rest of the semester. – For more information on BJT circuits, read S&S 4.12 15
he American Revolution simulation is designed to teach students about this important period of history by inviting them to relive that event . Over the course of five days, they will recreate some of the experiences of the people who were beginning a new nation . By taking the perspective of a historical character living through the event, students will begin to see that history is so much .
