1. Figure 7.12 The basic BJT differential-pair configuration.
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2. Figure Different modes of operation of the BJT differential pair: (a) The differential pair with a common-mode input signal vCM.
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3. Figure Different modes of operation of the BJT differential pair: The differential pair with a “large” differential input signal.
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4. Figure The differential pair with a large differential input signal of polarity opposite to that in (b).
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5. Figure 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.
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6. Figure 7.14 Transfer characteristics of the BJT differential pair of Fig. 7.12 assuming a = 1.
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7. Note that VOV is the overdrive voltage at which Q1 and Q2 operate
Figure 7.6 Normalized plots of the currents in a MOSFET differential pair.
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Note that VOV is the overdrive voltage at which Q1 and Q2 operate
when conducting drain currents equal to I/2.

8. Figure 7.15 The transfer characteristics of the BJT differential pair
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The linear range of operation can be extended
by including resistances in the emitters.

9. Exercise 7.8

10. Figure The currents and voltages in the differential amplifier when a small differential input signal vid is applied.
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11. Figure A simple technique for determining the signal currents in a differential amplifier excited by a differential voltage signal vid; dc quantities are not shown.
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12. Figure 7. 18 A differential amplifier with emitter resistances
Figure A differential amplifier with emitter resistances. Only signal quantities are shown (in color).
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13. Figure 7.19 Equivalence of the BJT differential amplifier :
Two common-emitter amplifiers
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14. Figure 7.20 The differential amplifier fed in a single-ended fashion.
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15. Quiz # 2 (Syn A)
For the BJT Differential Pair shown in the given figure, find the value of the input differential signal vid = vB1 – vB2, that causes iE1 = 0.80I.

16. Quiz # 2 (Syn B)
Using the above two equations, plot the collector currents iC1 and iC2 (normalized to the total bias current I) versus the normalized differential input voltage vid/VT.

17. Figure 7.19 Equivalence of the BJT differential amplifier :
Two common-emitter amplifiers
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18. Figure 7.4 The MOS differential pair with a differential input signal vid applied.
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19. Figure 7.20 The differential amplifier fed in a single-ended fashion.
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20. Figure 7.21 The differential half-circuit and its equivalent circuit model
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21. Figure 7.22 The differential amplifier fed by a common-mode voltage signal vicm.
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22. Figure 7. 23 (a) Definition of the input common-mode resistance Ricm
Figure (a) Definition of the input common-mode resistance Ricm. (b) The equivalent common-mode half-circuit.
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23. Figure 7.24 Circuit for Example 7.1.
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