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Chapter 2 – Operational Amplifiers
Introduction
http://engr.calvin.edu/PRibeiro_WEBPAGE/courses/engr311/Handouts/OpAmp-tutorial-1.ppt
Textbook CD
http://www.clarkson.edu/%7Esvoboda/eta/designLab/InvertingAmplifierDesign.html
The OP-AMP Terminals
Symbol
Power Supplies
Fairchild uA702 – The first op-amp designed by Bob Widlar
The OP-AMP Terminals
The OP-AMP Terminals
The Ideal OP-AMP
Inverting
_
i(-)
RO
vid
Noninverting
i(+)
Ri
Output
vO = Advid
A
+
-VS
Open-loop gain
Exercise 2.2
Analysis of Circuits Containing Ideal OP-AMPS
The Inverting Configuration
Closed-Loop Gain
Virtual Short-Circuit
Virtual Ground
Negative and Positive Feedback
The inverting closed-loop configuration.
Analysis of Circuits Containing Ideal OP-AMPS
The Closed-Loop Gain
-
Analysis of the inverting configuration
Analysis of Circuits Containing Ideal OP-AMPS
Effect of Finite Open-Loop Gain
i1
vo
 v o 
vI  

 A 
vI 
R1
v o
A
A
R1
vo

v o  v I  A

A
 R1
 i1 R2
 R2
G
vo
vo
R1
vI
 1  R2 


R1 

1
A


  R2

Analysis of Circuits Containing Ideal OP-AMPS
Exercise 2.1
Analysis of Circuits Containing Ideal OP-AMPS
Input and Output Resistances
Ri
vI
vI
iI
vI
R1
Ro
0
R1
Analysis of Circuits Containing Ideal OP-AMPS
Exercise 2.2
Other Applications of the Inverting Configuration
With General Impedances
R2
Z2
i
s
R1
Z1
vo
vs
+
Other Applications of the Inverting Configuration
The Integrator
i
is
t
c
C
v o ( t)
R
0
ivs
1 
  v I( t) d t
C R 
+
vo
Vo
1
VI
s  C R
Other Applications of the Inverting Configuration
PSpice Simulation Tips
Other Applications of the Inverting Configuration
The Differentiator
Z2 = R
R2
Z1 = 1/sC
i
s
R1
vo
vs
+
Other Applications of the Inverting Configuration
The Weighted Summer
Other Applications of the Inverting Configuration
The Non-Inverting Configuration
v2  v1
vo
vI 
vo
A
vI
R1
vi
vo
vI
1
R2
R1
A
 R2
infinite
Other Applications of the Inverting Configuration
The Voltage Follower
Other Applications of the Inverting Configuration
The Difference Amplifier
A difference amplifier.
Other Applications of the Inverting Configuration
The Difference Amplifier
Applications of superposition to the analysis of the current circuit of Fig.. 2.21.
Other Applications of the Inverting Configuration
The Difference Amplifier – Input Resistances
Finding the input resistance of the difference amplifier.
Other Applications of the Inverting Configuration
The Difference Amplifier – Common-Mode and Differential
Components of the input signal
Representation of the common-mode and differential components of the input signal to a difference amplifier. Note that v1 = vCM - vd/2
and v2 = vCM + vd/2.
Other Applications of the Inverting Configuration
Instrumentation Amplifier
(a) A popular circuit for an instrumentation amplifier. (b) Analysis of the circuit in (a) assuming ideal op-amps. (c) To make the gain
variable, R1 is implemented as the series combination of a fixed resister R1f and a variable resistor R1v. Resistor R1f ensures that the
maximum available gain is limited.
Effect Of Finite Open-Loop Gain and Bandwidth On Circuit
Performance
Open-loop gain of a typical general-purpose internally
compensated op amp.
fb = 3-db or break frequency
ft = unity gain bandwidth
(a) Unity-gain follower. (b) Input step waveform. (c) Linearly rising output waveform obtained when the amplifier is slew-rate
limited. (d) Exponentially rising output waveform obtained when V is sufficiently small so that the initial slope (wtV) is smaller then or
equal to SR.
Effect of slew-rate limiting on output sinusoidal waveforms.