1. 1 Bipolar Junction Transistors (BJTs)

2. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith2 Figure 5.1 A simplified structure of the npn transistor.

3. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith3 Figure 5.2 A simplified structure of the pnp transistor.

4. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith4

5. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith5 Figure 5.3 Current flow in an npn transistor biased to operate in the active mode. (Reverse current components due to drift of thermally generated minority carriers are not shown.)

6. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith6 Figure 5.4 Profiles of minority-carrier concentrations in the base and in the emitter of an npn transistor operating in the active mode: v BE  0 and v CB  0.

7. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith7

8. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith8

9. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith9

10. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith10

11. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith11 Figure 5.5 Large-signal equivalent-circuit models of the npn BJT operating in the forward active mode.

12. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith12 Figure 5.6 Cross-section of an npn BJT.

13. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith13 Figure 5.7 Model for the npn transistor when operated in the reverse active mode (i.e., with the CBJ forward biased and the EBJ reverse biased).

14. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith14 Figure 5.8 The Ebers-Moll (EM) model of the npn transistor.

15. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith15

16. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith16

17. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith17

18. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith18 Figure 5.9 The i C – v CB characteristic of an npn transistor fed with a constant emitter current I E. The transistor enters the saturation mode of operation for v CB  –0.4 V, and the collector current diminishes.

19. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith19 Figure 5.10 Concentration profile of the minority carriers (electrons) in the base of an npn transistor operating in the saturation mode.

20. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith20 Figure 5.11 Current flow in a pnp transistor biased to operate in the active mode.

21. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith21 Figure 5.12 Large-signal model for the pnp transistor operating in the active mode.

22. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith22 Figure 5.13 Circuit symbols for BJTs.

23. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith23 Figure 5.14 Voltage polarities and current flow in transistors biased in the active mode.

24. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith24

25. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith25 Figure 5.15 Circuit for Example 5.1. EXAMPLE 5.1

26. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith26

27. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith27 Figure E5.10

28. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith28 Figure E5.11

29. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith29 Figure 5.16 The i C – v BE characteristic for an npn transistor.

30. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith30 Figure 5.17 Effect of temperature on the i C – v BE characteristic. At a constant emitter current (broken line), v BE changes by –2 mV/  C.

31. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith31 Figure 5.18 The i C – v CB characteristics of an npn transistor.

32. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith32 Figure 5.19 (a) Conceptual circuit for measuring the i C – v CE characteristics of the BJT. (b) The i C – v CE characteristics of a practical BJT.

33. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith33

34. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith34 Figure 5.20 Large-signal equivalent-circuit models of an npn BJT operating in the active mode in the common-emitter configuration.

35. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith35 Figure 5.21 Common-emitter characteristics. Note that the horizontal scale is expanded around the origin to show the saturation region in some detail.

36. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith36 Figure 5.22 Typical dependence of  on I C and on temperature in a modern integrated-circuit npn silicon transistor intended for operation around 1 mA.

37. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith37 Figure 5.23 An expanded view of the common-emitter characteristics in the saturation region.

38. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith38

39. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith39 Figure 5.24 (a) An npn transistor operated in saturation mode with a constant base current I B. (b) The i C – v CE characteristic curve corresponding to i B = I B. The curve can be approximated by a straight line of slope 1/R CEsat. (c) Equivalent-circuit representation of the saturated transistor. (d) A simplified equivalent-circuit model of the saturated transistor.

40. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith40

41. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith41 Figure 5.25 Plot of the normalized i C versus v CE for an npn transistor with  F = 100 and  R = 0.1. This is a plot of Eq. (5.47), which is derived using the Ebers-Moll model.

42. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith42

43. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith43 Figure E5.18 BV BCO =70 V

44. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith44

45. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith45

46. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith46

47. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith47

48. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith48

49. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith49 Figure 5.26 (a) Basic common-emitter amplifier circuit. (b) Transfer characteristic of the circuit in (a). The amplifier is biased at a point Q, and a small voltage signal v i is superimposed on the dc bias voltage V BE. The resulting output signal v o appears superimposed on the dc collector voltage V CE. The amplitude of v o is larger than that of v i by the voltage gain A v.

50. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith50

51. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith51

52. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith52

53. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith53 EXAMPLE 5.2

54. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith54

55. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith55 Figure 5.27 Circuit whose operation is to be analyzed graphically.

56. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith56 Figure 5.28 Graphical construction for the determination of the dc base current in the circuit of Fig. 5.27.

57. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith57 Figure 5.29 Graphical construction for determining the dc collector current I C and the collector-to-emitter voltage V CE in the circuit of Fig. 5.27.

58. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith58 Figure 5.30 Graphical determination of the signal components v be, i b, i c, and v ce when a signal component v i is superimposed on the dc voltage V BB (see Fig. 5.27).

59. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith59 Figure 5.31 Effect of bias-point location on allowable signal swing: Load-line A results in bias point Q A with a corresponding V CE which is too close to V CC and thus limits the positive swing of v CE. At the other extreme, load-line B results in an operating point too close to the saturation region, thus limiting the negative swing of v CE.

60. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith60 Figure 5.32 A simple circuit used to illustrate the different modes of operation of the BJT.

61. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith61

62. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith62

63. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith63 Figure 5.33 Circuit for Example 5.3. EXAMPLE 5.3

64. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith64

65. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith65 Figure 5.34 Analysis of the circuit for Example 5.4: (a) circuit; (b) circuit redrawn to remind the reader of the convention used in this book to show connections to the power supply; (c) analysis with the steps numbered.

66. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith66 EXAMPLE 5.4

67. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith67 Figure 5.35 Analysis of the circuit for Example 5.5. Note that the circled numbers indicate the order of the analysis steps.

68. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith68 EXAMPLE 5.5

69. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith69

70. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith70 Figure 5.36 Example 5.6: (a) circuit; (b) analysis with the order of the analysis steps indicated by circled numbers. EXAMPLE 5.6

71. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith71 Figure 5.37 Example 5.7: (a) circuit; (b) analysis with the steps indicated by circled numbers. EXAMPLE 5.7

72. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith72

73. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith73 Figure 5.38 Example 5.8: (a) circuit; (b) analysis with the steps indicated by the circled numbers. EXAMPLE 5.8

74. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith74

75. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith75 Figure 5.39 Example 5.9: (a) circuit; (b) analysis with steps numbered. EXAMPLE 5.9

76. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith76

77. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith77

78. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith78 Figure 5.40 Circuits for Example 5.10.

79. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith79 EXAMPLE 5.10

80. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith80

81. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith81 Figure 5.41 Circuits for Example 5.11. EXAMPLE 5.11

82. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith82

83. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith83

84. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith84 Figure E5.30

85. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith85 Figure 5.42 Example 5.12: (a) circuit; (b) analysis with the steps numbered. EXAMPLE 5.12

86. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith86 Figure 5.43 Two obvious schemes for biasing the BJT: (a) by fixing V BE ; (b) by fixing I B. Both result in wide variations in I C and hence in V CE and therefore are considered to be “bad.” Neither scheme is recommended. 5.5 Constant Ic

87. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith87 Figure 5.44 Classical biasing for BJTs using a single power supply: (a) circuit; (b) circuit with the voltage divider supplying the base replaced with its Thévenin equivalent.

88. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith88

89. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith89 EXAMPLE 5.13 I E =1mA, V CC =12V

90. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith90

91. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith91 Figure 5.45 Biasing the BJT using two power supplies. Resistor R B is needed only if the signal is to be capacitively coupled to the base. Otherwise, the base can be connected directly to ground, or to a grounded signal source, resulting in almost total  -independence of the bias current.

92. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith92 Figure 5.46 (a) A common-emitter transistor amplifier biased by a feedback resistor R B. (b) Analysis of the circuit in (a).

93. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith93

94. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith94 Figure 5.47 (a) A BJT biased using a constant-current source I. (b) Circuit for implementing the current source I.

95. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith95 Figure 5.48 (a) Conceptual circuit to illustrate the operation of the transistor as an amplifier. (b) The circuit of (a) with the signal source v be eliminated for dc (bias) analysis.

96. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith96

97. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith97

98. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith98

99. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith99 Figure 5.49 Linear operation of the transistor under the small-signal condition: A small signal v be with a triangular waveform is superimposed on the dc voltage V BE. It gives rise to a collector signal current i c, also of triangular waveform, superimposed on the dc current I C. Here, i c = g m v be, where g m is the slope of the i C – v BE curve at the bias point Q.

100. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith100

101. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith101

102. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith102

103. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith103

104. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith104 Figure 5.50 The amplifier circuit of Fig. 5.48(a) with the dc sources (V BE and V CC ) eliminated (short circuited). Thus only the signal components are present. Note that this is a representation of the signal operation of the BJT and not an actual amplifier circuit.

105. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith105 Figure 5.51 Two slightly different versions of the simplified hybrid-  model for the small-signal operation of the BJT. The equivalent circuit in (a) represents the BJT as a voltage-controlled current source (a transconductance amplifier), and that in (b) represents the BJT as a current- controlled current source (a current amplifier).

106. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith106 Figure 5.52 Two slightly different versions of what is known as the T model of the BJT. The circuit in (a) is a voltage-controlled current source representation and that in (b) is a current-controlled current source representation. These models explicitly show the emitter resistance r e rather than the base resistance r  featured in the hybrid-  model.

107. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith107

108. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith108 Figure 5.53 Example 5.14: (a) circuit; (b) dc analysis; (c) small-signal model.  =100 Voltage gain?

109. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith109 EXAMPLE 5.14

110. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith110

111. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith111 EXAMPLE 5.15

112. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith112 Figure 5.54 Signal waveforms in the circuit of Fig. 5.53.

113. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith113 Figure 5.55 Example 5.16: (a) circuit; (b) dc analysis; (c) small-signal model; (d) small-signal analysis performed directly on the circuit.

114. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith114 EXAMPLE 5.16

115. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith115 Figure 5.56 Distortion in output signal due to transistor cutoff. Note that it is assumed that no distortion due to the transistor nonlinear characteristics is occurring.

116. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith116 Figure 5.57 Input and output waveforms for the circuit of Fig. 5.55. Observe that this amplifier is noninverting, a property of the common-base configuration.

117. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith117 Figure 5.58 The hybrid-  small-signal model, in its two versions, with the resistance r o included.

118. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith118 Figure E5.40

119. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith119

120. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith120

121. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith121 Figure 5.59 Basic structure of the circuit used to realize single-stage, discrete-circuit BJT amplifier configurations.

122. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith122 Figure E5.41

123. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith123

124. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith124 Table 5.5

125. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith125

126. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith126

127. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith127 EXAMPLE 5.17

128. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith128

129. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith129

130. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith130

131. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith131

132. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith132 Figure 5.60 (a) A common-emitter amplifier using the structure of Fig. 5.59. (b) Equivalent circuit obtained by replacing the transistor with its hybrid-  model.

133. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith133

134. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith134

135. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith135

136. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith136 Figure 5.61 (a) A common-emitter amplifier with an emitter resistance R e. (b) Equivalent circuit obtained by replacing the transistor with its T model.

137. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith137

138. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith138

139. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith139

140. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith140

141. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith141 Figure 5.62 (a) A common-base amplifier using the structure of Fig. 5.59. (b) Equivalent circuit obtained by replacing the transistor with its T model.

142. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith142

143. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith143

144. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith144 Figure 5.63 (a) An emitter-follower circuit based on the structure of Fig. 5.59. (b) Small-signal equivalent circuit of the emitter follower with the transistor replaced by its T model augmented with r o. (c) The circuit in (b) redrawn to emphasize that r o is in parallel with R L. This simplifies the analysis considerably.

145. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith145 Figure 5.64 (a) An equivalent circuit of the emitter follower obtained from the circuit in Fig. 5.63(c) by reflecting all resistances in the emitter to the base side. (b) The circuit in (a) after application of Thévenin theorem to the input circuit composed of v sig, R sig, and R B.

146. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith146

147. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith147 Figure 5.65 (a) An alternate equivalent circuit of the emitter follower obtained by reflecting all base-circuit resistances to the emitter side. (b) The circuit in (a) after application of Thévenin theorem to the input circuit composed of v sig, R sig / (  1 1), and R B / (  1 1).

148. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith148

149. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith149

150. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith150 Figure 5.66 Thévenin equivalent circuit of the output of the emitter follower of Fig. 5.63(a). This circuit can be used to find v o and hence the overall voltage gain v o / v sig for any desired R L.

151. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith151

152. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith152

153. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith153

154. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith154

155. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith155

156. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith156

157. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith157

158. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith158 Figure 5.67 The high-frequency hybrid-  model.

159. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith159 Figure 5.68 Circuit for deriving an expression for h fe (s) ; I c /I b.

160. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith160

161. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith161

162. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith162 Figure 5.69 Bode plot for u h fe u.

163. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith163 Figure 5.70 Variation of f T with I C.

164. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith164

165. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith165 Figure 5.71 (a) Capacitively coupled common-emitter amplifier. (b) Sketch of the magnitude of the gain of the CE amplifier versus frequency. The graph delineates the three frequency bands relevant to frequency-response determination.

166. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith166

167. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith167 Figure 5.72 Determining the high-frequency response of the CE amplifier: (a) equivalent circuit; (b) the circuit of (a) simplified at both the input side and the output side; (c) equivalent circuit with C  replaced at the input side with the equivalent capacitance C eq ; (d) sketch of the frequency- response plot, which is that of a low-pass STC circuit.

168. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith168

169. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith169

170. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith170 EXAMPLE 5.18 I=1 mA R B =100 kohm R sig = 5 kohm R L =5 kohm R C =3 kohm  o =100 V A =100 C µ = 1 pF f T =800 MHz r x = 50 ohm

171. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith171

172. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith172

173. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith173 Figure 5.73 Analysis of the low-frequency response of the CE amplifier: (a) amplifier circuit with dc sources removed; (b) the effect of C C1 is determined with C E and C C2 assumed to be acting as perfect short circuits;

174. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith174 Figure 5.73 (Continued) (c) the effect of C E is determined with C C1 and C C2 assumed to be acting as perfect short circuits; (d) the effect of C C2 is determined with C C1 and C E assumed to be acting as perfect short circuits;

175. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith175 Figure 5.73 (Continued) (e) sketch of the low-frequency gain under the assumptions that C C1, C E, and C C2 do not interact and that their break (or pole) frequencies are widely separated.

176. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith176

177. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith177

178. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith178

179. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith179

180. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith180 EXAMPLE 5.19

181. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith181

182. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith182 Figure 5.74 Basic BJT digital logic inverter.

183. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith183 Figure 5.75 Sketch of the voltage transfer characteristic of the inverter circuit of Fig. 5.74 for the case R B 5 10 k , R C 5 1 k ,  5 50, and V CC 5 5 V. For the calculation of the coordinates of X and Y, refer to the text.

184. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith184

185. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith185

186. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith186 Figure 5.76 The minority-carrier charge stored in the base of a saturated transistor can be divided into two components: That in blue produces the gradient that gives rise to the diffusion current across the base, and that in gray results from driving the transistor deeper into saturation.

187. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith187 Figure E5.53

188. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith188 Figure 5.77 The transport form of the Ebers-Moll model for an npn BJT.

189. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith189

190. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith190 Figure 5.78 The SPICE large-signal Ebers-Moll model for an npn BJT.

191. Copyright  2004 by Oxford University Press, Inc. 191

192. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith192 EXAMPLE 5.20

193. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith193 Figure 5.79 The PSpice testbench used to demonstrate the dependence of  dc on the collector bias current I C for the Q2N3904 discrete BJT (Example 5.20).

194. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith194 Figure 5.80 Dependence of  dc on I C (at V CE 5 2 V) in the Q2N3904 discrete BJT (Example 5.20).

195. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith195 Figure 5.81 Capture schematic of the CE amplifier in Example 5.21. EXAMPLE 5.21

196. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith196

197. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith197

198. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith198 Figure 5.82 Frequency response of the CE amplifier in Example 5.21 with R ce = 0 and R ce = 130 .

199. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith199

200. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith200 Figure P5.20

201. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith201 Figure P5.21

202. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith202 Figure P5.24

203. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith203 Figure P5.26

204. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith204 Figure P5.36

205. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith205 Figure P5.44

206. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith206 Figure P5.53

207. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith207 Figure P5.57

208. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith208 Figure P5.58

209. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith209 Figure P5.65

210. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith210 Figure P5.66

211. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith211 Figure P5.67

212. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith212 Figure P5.68

213. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith213 Figure P5.69

214. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith214 Figure P5.71

215. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith215 Figure P5.72

216. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith216 Figure P5.74

217. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith217 Figure P5.76

218. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith218 Figure P5.78

219. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith219 Figure P5.79

220. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith220 Figure P5.81

221. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith221 Figure P5.82

222. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith222 Figure P5.83

223. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith223 Figure P5.84

224. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith224 Figure P5.85

225. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith225 Figure P5.86

226. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith226 Figure P5.87

227. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith227 Figure P5.96

228. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith228 Figure P5.97

229. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith229 Figure P5.98

230. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith230 Figure P5.99

231. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith231 Figure P5.100

232. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith232 Figure P5.101

233. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith233 Figure P5.112

234. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith234 Figure P5.115

235. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith235 Figure P5.116

236. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith236 Figure P5.124

237. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith237 Figure P5.126

238. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith238 Figure P5.130

239. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith239 Figure P5.134

240. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith240 Figure P5.135

241. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith241 Figure P5.136

242. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith242 Figure P5.137

243. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith243 Figure P5.141

244. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith244 Figure P5.143

245. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith245 Figure P5.144

246. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith246 Figure P5.147

247. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith247 Figure P5.148

248. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith248 Figure P5.159

249. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith249 Figure P5.161

250. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith250 Figure P5.162

251. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith251 Figure P5.166

252. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith252 Figure P5.167

253. Copyright  2004 by Oxford University Press, Inc. Microelectronic Circuits - Fifth Edition Sedra/Smith253 Figure P5.171