PowerPoint PresentationSlide 2Slide 3Slide 4Slide 5Slide 6Slide 7Slide 8Slide 9Slide 10Slide 11Slide 12Slide 13Slide 14Slide 15Slide 16Slide 17Slide 18Slide 19Slide 20Slide 21Slide 22Slide 23Slide 24Slide 25Slide 26Slide 27Slide 28Slide 29Slide 30Slide 31Slide 32Slide 33Slide 34Slide 35Slide 36Slide 37Slide 38Slide 39Slide 40Slide 41Slide 42Slide 43Slide 44Slide 45Slide 46Slide 47Slide 48Slide 49Slide 50Slide 51Slide 52Slide 53Slide 54Slide 55Slide 56Slide 57Slide 58Slide 59Slide 60Slide 61Slide 62Slide 63Slide 64Slide 65Slide 66Slide 67Slide 68Slide 69Slide 70Slide 71Slide 72Slide 73Slide 74Slide 75Slide 76Slide 77Slide 78Slide 79Slide 80Slide 811Differential and MultistageAmplifiersMicroelectronic Circuits - Fifth Edition Sedra/Smith 2Copyright  2004 by Oxford University Press, Inc.Figure 7.1 The basic MOS differential-pair configuration.Microelectronic Circuits - Fifth Edition Sedra/Smith 3Copyright  2004 by Oxford University Press, Inc.Figure 7.2 The MOS differential pair with a common-mode input voltage vCM.Microelectronic Circuits - Fifth Edition Sedra/Smith 4Copyright  2004 by Oxford University Press, Inc.Figure 7.3 Circuits for Exercise 7.1. Effects of varying vCM on the operation of the differential pair.Microelectronic Circuits - Fifth Edition Sedra/Smith 5Copyright  2004 by Oxford University Press, Inc.Figure 7.3 (Continued)Microelectronic Circuits - Fifth Edition Sedra/Smith 6Copyright  2004 by Oxford University Press, Inc.Figure 7.4 The MOS differential pair with a differential input signal vid applied. With vid positive: vGS1  vGS2, iD1  iD2, and vD1  vD2; thus (vD2  vD1) will be positive. With vid negative: vGS1  vGS2, iD1  iD2, and vD1  vD2; thus (vD2  vD1) will be negative.Microelectronic Circuits - Fifth Edition Sedra/Smith 7Copyright  2004 by Oxford University Press, Inc.Figure 7.5 The MOSFET differential pair for the purpose of deriving the transfer characteristics, iD1 and iD2 versus vid  vG1 – vG2.Microelectronic Circuits - Fifth Edition Sedra/Smith 8Copyright  2004 by Oxford University Press, Inc.Figure 7.6 Normalized plots of the currents in a MOSFET differential pair. Note that VOV is the overdrive voltage at which Q1 and Q2 operate when conducting drain currents equal to I/2.Microelectronic Circuits - Fifth Edition Sedra/Smith 9Copyright  2004 by Oxford University Press, Inc.Figure 7.7 The linear range of operation of the MOS differential pair can be extended by operating the transistor at a higher value of VOV.Microelectronic Circuits - Fifth Edition Sedra/Smith 10Copyright  2004 by Oxford University Press, Inc.Figure 7.8 Small-signal analysis of the MOS differential amplifier: (a) The circuit with a common-mode voltage applied to set the dc bias voltage at the gates and with vid applied in a complementary (or balanced) manner. (b) The circuit prepared for small-signal analysis. (c) An alternative way of looking at the small-signal operation of the circuit.Microelectronic Circuits - Fifth Edition Sedra/Smith 11Copyright  2004 by Oxford University Press, Inc.Figure 7.9 (a) MOS differential amplifier with ro and RSS taken into account. (b) Equivalent circuit for determining the differential gain. Each of the two halves of the differential amplifier circuit is a common-source amplifier, known as its differential “half-circuit.”Microelectronic Circuits - Fifth Edition Sedra/Smith 12Copyright  2004 by Oxford University Press, Inc.Figure 7.10 (a) The MOS differential amplifier with a common-mode input signal vicm. (b) Equivalent circuit for determining the common-mode gain (with ro ignored). Each half of the circuit is known as the “common-mode half-circuit.”Microelectronic Circuits - Fifth Edition Sedra/Smith 13Copyright  2004 by Oxford University Press, Inc.Figure 7.11 Analysis of the MOS differential amplifier to determine the common-mode gain resulting from a mismatch in the gm values of Q1 and Q2.Microelectronic Circuits - Fifth Edition Sedra/Smith 14Copyright  2004 by Oxford University Press, Inc.Figure 7.12 The basic BJT differential-pair configuration.Microelectronic Circuits - Fifth Edition Sedra/Smith 15Copyright  2004 by Oxford University Press, Inc.Figure 7.13 Different modes of operation of the BJT differential pair: (a) The differential pair with a common-mode input signal vCM. (b) The differential pair with a “large” differential input signal.Microelectronic Circuits - Fifth Edition Sedra/Smith 16Copyright  2004 by Oxford University Press, Inc.Figure 7.13 (Continued) (c) The differential pair with a large differential input signal of polarity opposite to that in (b). (d) The differential pair with a small differential input signal vi. Note that we have assumed the bias current source I to be ideal (i.e., it has an infinite output resistance) and thus I remains constant with the change in vCM.Microelectronic Circuits - Fifth Edition Sedra/Smith 17Copyright  2004 by Oxford University Press, Inc.Figure E7.7Microelectronic Circuits - Fifth Edition Sedra/Smith 18Copyright  2004 by Oxford University Press, Inc.Figure 7.14 Transfer characteristics of the BJT differential pair of Fig. 7.12 assuming  . 1.Microelectronic Circuits - Fifth Edition Sedra/Smith 19Copyright  2004 by Oxford University Press, Inc.Figure 7.15 The transfer characteristics of the BJT differential pair (a) can be linearized (b) (i.e., the linear range of operation can be extended) by including resistances in the emitters.Microelectronic Circuits - Fifth Edition Sedra/Smith 20Copyright  2004 by Oxford University Press, Inc.Figure 7.16 The currents and voltages in the differential amplifier when a small differential input signal vid is applied.Microelectronic Circuits - Fifth Edition Sedra/Smith 21Copyright  2004 by Oxford University Press, Inc.Figure 7.17 A simple technique for determining the signal currents in a differential amplifier excited by a differential voltage signal vid; dc quantities are not shown.Microelectronic Circuits - Fifth Edition Sedra/Smith 22Copyright  2004 by Oxford University Press, Inc.Figure 7.18 A differential amplifier with emitter resistances. Only signal quantities are shown (in color).Microelectronic Circuits - Fifth Edition Sedra/Smith 23Copyright  2004 by Oxford University Press, Inc.Figure 7.19 Equivalence of the BJT differential amplifier in (a) to the two