Transistor Amplifiers BJT - York University · CHAPTER 7 Transistor Amplifiers BJT ... Figure 7.33 The basic configurations of transistor amplifiers. (a)–(c) For the MOSFET; (d)–(f)

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Microelectronic Circuits, Seventh Edition Sedra/Smith Copyright © 2015 by Oxford University Press

CHAPTER 7

Transistor Amplifiers

BJT

Disclaimer: Most of the slides are skeletons that will be filled/modified in the lecture. Please do not assume that you can know the material just by reading the slides.


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Figure 7.2 (a) An NMOS amplifier and (b) its VTC; and (c) a nnpn amplifier and (d) its

VTC.


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Figure 7.22 Illustrating the definition of rπ and re.

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Figure 7.23 The amplifier circuit of Fig. 7.20(a) with the dc sources (VBE and VCC) 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.


Figure 7.24 Two slightly different versions of the hybrid-π 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).

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Figure 7.25 The hybrid-π small-signal model, in its two versions, with the resistance ro included.

CAo

mBT

TCm

IVr

gIVr

VIg

/

//

/


mETe

TCm

gIVr

VIg

//

/

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Figure 7.27 The T models of the BJT.

CAo

mETe

TCm

IVr

gIVr

VIg

/

//

/


8.10)99/3.2/(25/

09.192/100/

/9225/3.2/

ETe

m

TCm

IVr

Kgr

VmAVIg

100

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ie

Ce

Ceo

eie

vr

Ri

Riv

rvi

/


Figure 7.31 Input and output waveforms for the circuit of Fig. 7.30. Observe that this amplifier is

noninverting, a property of the grounded-base configuration.

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Performing Small Signal Analysis Directly on the Circuit



Figure E7.20

=100 VA=100Va) Find VA, VB, and VC ignoring Early

Effectb) Find gm, r, ro

c) Z is grounded and vsig is connected to X (with 2K internal R, and 8K load resistance connected to Y find Av with or without the Early effect

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Figure 7.33 The basic configurations of transistor amplifiers. (a)–(c) For the MOSFET; (d)–(f)

for the BJT.

Amplifiers


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Common Emitter



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Common Base


Common Collector – Emitter Follower


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Transistor Amplifiers BJT - York University · CHAPTER 7 Transistor Amplifiers BJT ... Figure 7.33 The basic configurations of transistor amplifiers. (a)–(c) For the MOSFET; (d)–(f)