Adel S.Sedra微电子电路期中复习PPT

1、Microelectronic CircuitsSJTU Yang HuaReview2011-04-2SJTU Yang HuaMicroelectronic CircuitsCharacteristics of this subject:lEngineering(1) Pay more attention to qualitative analysis(2) quantitative analysis：approximately computing，especially for nonlinear circuits(3) Approximately computing should be

2、“reasonable”(4) Different parameters should be estimated by different models. lPractice the design and debug of your circuits using EDA tools and real measure devices SJTU Yang HuaMicroelectronic CircuitsHow to study this subject:lMaster three basic: Basic concept, basic circuit and basic analysis m

3、ethodslall things considered and dialectically analyze the circuitslThe applications of basic theorem and Laws: For example, Kirchhoffs law, Thevenin theorem, Norton theorem, ohm theorem and so on. SJTU Yang HuaMicroelectronic CircuitsThe Content of microelectronic circuits Microelectronic CircuitsS

4、JTU Yang HuaDiodesSJTU Yang HuaMicroelectronic CircuitsDiodes:1.Basic Concept:lIntrinsic Semiconductor (本征半导体)lCarriers (载流子)lThermal ionization (热激发)lRecombination(复合)lThermal equilibrium（热平衡）lDoped Semiconductor (掺杂半导体)lP type semiconductor (P型半导体)lN type semiconductor (N型半导体)lDiffusion (扩散运动), Dr

5、ift (漂移运动)SJTU Yang HuaMicroelectronic Circuitsl Majority carriers- Majority carrier is only determined by the impurity, but independent of temperature l Minority carriers-only generated by thermal ionization and are strongly affected by temperature .Basic Concept:donoracceptorMajority carriersMinor

6、ity carriersN typepentavalentPhosphrus Free electronsholesP typetrivalentBoronholesFree electronsSJTU Yang HuaMicroelectronic CircuitsSome important results:lA free electron is negative charge and a hole is positive charge. lAt a steady temperature, the recombination rate is equal to the ionization

7、rate.lCarrier concentration in thermal equilibriuminpnkTEiGeBTn32SJTU Yang HuaMicroelectronic CircuitsIntrinsic Semiconductor(contd)Important notes:l has a strong function of temperature. The high the temperature is, the dramatically great the carrier concentration is.lAt room temperature only one o

8、f every billion atoms is ionized.lSilicons conductivity is between that of conductors and insulators. Actually the characteristic of intrinsic silicon approaches to insulators. inSJTU Yang HuaMicroelectronic CircuitsCharacteristics of Silicon Junction Diodes) 1TnVvseIi（snVvsnVvsIeIeIiTT) 1(Forward b

9、iasedReverse biasedSJTU Yang HuaMicroelectronic CircuitsThe Diode Models and applicationsCircuit Modela)Simplified diode modelb)The constant-voltage-drop modelc)Small-signal modeld)Ideal modele)Zener Diode ModelThe circuit models are derived from approximating the nonlinear curve into piecewise-line

10、.Modeling the diode Forward characteristicModeling the diode Breakdown characteristic)2 , 1(,nInVrDQTdMicroelectronic CircuitsSJTU Yang HuaBJTsSJTU Yang HuaMicroelectronic CircuitsPhysical Structureemitter region (n type) base region (p type) collector region (n type)emitter (E) base (B) collector (

11、C) emitter-base junction (EBJ)collector-base junction (CBJ). Three regions:Three terminalsTwo pn junctions:SJTU Yang HuaMicroelectronic CircuitsOperation ModesModesEBJCBJApplicationCutoffReverseReverseSwitching application in digital circuitsSaturationForwardForwardActiveForwardReverseAmplifierlDepe

12、nding on the bias condition (forward or reverse) of each of the two junctions, there are different modes of operation of the BJT. lIn this course, we are mainly interested in the amplification mode.SJTU Yang HuaMicroelectronic CircuitsCurrent-voltage Characteristics lInput curve is similar to that o

13、f the diode. BiiBSJTU Yang HuaMicroelectronic CircuitsOutput Curves for CB ConfigurationSJTU Yang HuaMicroelectronic CircuitsThe equivalent circuit in (a) represents the BJT as a voltage-controlled current source (a transconductance amplifier), The equivalent circuit in (b) represents the BJT as a c

14、urrent-controlled current source (a current amplifier).The Hybrid- ModelSJTU Yang HuaMicroelectronic CircuitsThese models explicitly show the emitter resistance re rather than the base resistance r featured in the hybrid- model.The T ModelSJTU Yang HuaMicroelectronic CircuitsSummary of model paramet

15、ersCTBTTCmIVIVrVIgCAoCTETeIVrIVIVrmmegrgr,(1) Model parameters in terms of DC bias currents:(2) Model parameters in terms of gm:(3) Model parameters in terms of re:(4) Relationships between and :emeemrrgrrrg11,1,111,1,1SJTU Yang HuaMicroelectronic CircuitsApplication of the small-signal equivalent c

16、ircuit-the analysis process(1)Determine the dc operating point of the BJT and in particular the Ic(2)Calculate the values of the small-signal model parameters:(3)Draw the AC circuit: eliminate the dc source by replacing each dc voltage source with a short circuit and each dc current source with an o

17、pen circuit(4)Replace the BJT with one of its small-signal equivalent circuit models(5)Analyze the resulting circuit to determine the required quantities, e.g. voltage gain, input resistance and output resistancemETemTCmgIVrgrVIg1,SJTU Yang HuaMicroelectronic CircuitslLarge voltage gainlInverting am

18、plifierlLarge current gainlInput resistance is relatively low.lOutput resistance is relatively high.lFrequency response is rather poor.Summary of CE amplifierSJTU Yang HuaMicroelectronic CircuitslVery low input resistancelHigh output resistancelShort-circuit current gain is nearly unitylHigh voltage

19、 gainlNoninverting amplifierlCurrent bufferlExcellent high-frequency performanceSummary of the CB AmplifierSJTU Yang HuaMicroelectronic CircuitslNoninverting amplifierlHigh input resistancelLow output resistancelVoltage gain is smaller than but very close to unitylLarge current gainlThe last or outp

20、ut stage of cascade amplifierlFrequency response is excellent wellSummary for CC Amplifier or Emitter-FollowerSJTU Yang HuaMicroelectronic CircuitslThe CE configuration is the best suited for realizing the amplifier gain. lIncluding RE provides performance improvements at the expense of gain reducti

21、on.lThe CB configuration only has the typical application in amplifier. Much superior high-frequency response.lThe emitter follower can be used as a voltage buffer and exists in output stage of a multistage amplifier. Summary and ComparisonsSJTU Yang HuaMicroelectronic Circuits2.5.3 the comparison o

22、f three basic amplifiers performancetypesCECCCBAmplificationvoltageYesNoYescurentYesYesNopowerstrongYesYesInput resistancemidhigh lowOutput resistancemid low midphaseReverseIn-phase In-phaseHigh frequency mid betterbestSJTU Yang HuaMicroelectronic CircuitsExercise:chapter3: Read the example3.6 and 3

23、.8电路如图所示，已知ui5sint (V)，二极管导通电压VDo0.7V。试画出ui与uO的波形，并标出幅值。 SJTU Yang HuaMicroelectronic Circuits已知所示电路中稳压管的稳定电压UZ6V，最小稳定电流IZmin5mA，最大稳定电流IZmax25mA。（1）分别计算UI为10V、15V、35V三种情况下 输出电压UO的值；（2）若UI35V时负载开路，则会出现什么现象?为什么？ SJTU Yang HuaMicroelectronic CircuitsChapter4：BJT已知图P2.10所示电路中晶体管的 100，r=1k。 （1）现已测得静态管压降U

24、CEQ6V，估算Rb约为多少千欧；（2）若测得和的有效值分别为1mV和100mV，则负载电阻RL为多少千欧？ SJTU Yang HuaMicroelectronic Circuits判断题：判断题：（1）在N型半导体中如果掺入足够量的三价元素，可将其改型为P型半导体。（ ）（2）因为N型半导体的多子是自由电子，所以它带负电。（ ）（3）PN结在无光照、无外加电压时，结电流为零。（ ）（4）处于放大状态的晶体管，集电极电流是多子漂移运动形成的。（ ）SJTU Yang HuaMicroelectronic Circuits（1）PN结加正向电压时，空间电荷区将 。 A. 变窄 B. 基本不变

25、C. 变宽（2）稳压管的稳压区是其工作在 。 A. 正向导通 B.反向截止 C.反向击穿（3）当晶体管工作在放大区时，发射结电压和集电结电压应为 。 A. 前者反偏、后者也反偏 B. 前者正偏、后者反偏 C. 前者正偏、后者也正偏TUUI eSMicroelectronic CircuitsSJTU Yang HuaFETsSJTU Yang HuaMicroelectronic CircuitslClassification of FETslMOSFETN channelP channellJFETP channelN channelIntroduction to FET Enhanceme

26、nt typeDepletion typeEnhancement typeDepletion typeSJTU Yang HuaMicroelectronic Circuits(a) An n-channel enhancement-type MOSFET with vGS and vDS applied and with the normal directions of current flow indicated.(b) The iDvDS characteristics for a device with kn (W/L) = 1.0 mA/V2.Output Characteristi

27、c Curves of NMOSSJTU Yang HuaMicroelectronic CircuitsBrief reviewlA MOSFET has four terminals. lThe bias between the Gate and the Source is used to control the channel which builds a conducting tunnel between the Drain and the Source. lThere are three operation region:lCut offlTriodelSaturationSJTU

28、Yang HuaMicroelectronic CircuitsBrief reviewlA MOSFET at saturation acts as a current source: lThe Drain current is controlled by the Gate voltage and is independent of the Drain voltagelPractically the channel length modulation effect will leads the slight dependence of the Drain current on its vol

29、tageSJTU Yang HuaMicroelectronic Circuits Biased voltage The transistor is turned off. Operating in cutoff region as a switch.tGSVv0DiCutoff RegionSJTU Yang HuaMicroelectronic CircuitsBiased voltageThe channel depth changes from uniform to tapered shape.Drain current is controlled not only by vDS bu

30、t also by vGStGSDStGSVvvVvDStGSnDSDStGSnDvVvLWkvvVvLWki)(21)(2Triode Regionprocess transcon- ductance parameterSJTU Yang HuaMicroelectronic CircuitsAssuming that the draint-source voltage is sufficiently small, the MOS operates as a linear resistanceOVntGSnVvDDSDSVLWkVVLWkivrGSGS1)(1Triode RegionSJT

31、U Yang HuaMicroelectronic CircuitsBiased voltageThe channel is pinched off.Drain current is controlled only by vGSDrain current is independent of vDS and behaves as an ideal current source.tGSDStGSVvvVv221)tGSnDVvLWki（Saturation RegionSJTU Yang HuaMicroelectronic Circuits(a) neglecting the the chann

32、el-length modulation effect(b) including the effect of channel-length modulation, modeled by output resistance ro = |VA| /ID.The Small-Signal ModelsSJTU Yang HuaMicroelectronic Circuits(a) The T model of the MOSFET augmented with the drain-to-source resistance ro. (b) An alternative representation o

33、f the T model.The Small-Signal ModelsSJTU Yang HuaMicroelectronic CircuitslInput resistancelVoltage gainlOverall voltage gainlOutput resistanceGinRR )/(LDomvRRrgA)/(oLDmsigGGvrRRgRRRGDooutRrR/Characteristics of CS AmplifierSJTU Yang HuaMicroelectronic CircuitslVery high input resistancelModerately h

34、igh voltage gainlRelatively high output resistanceSummary of CS AmplifierSJTU Yang HuaMicroelectronic CircuitslInput resistancelVoltage gainlOverall voltage gainlOutput resistancemingR1)/(LDmvRRgA sigmLDmvRgRRgG1)/(DoutRRCharacteristics of CG AmplifierSJTU Yang HuaMicroelectronic CircuitslNoninverting amplifierlLow input resistancelHas nearly identical voltage gain of CS amplifier, but the overall voltage gain is smaller by the factor (1+gmRsig）lRelati