Chapter 2 – Operational Amplifiers Introduction tp:// engr . calvin .edu/ PRibeiro _WEBPAGE/courses/engr311/Handouts/ OpAmp -tutoria xtbook CD tp://www.clarkson.edu/%7Esvoboda/eta/designLab/InvertingAmplifierDesign.html
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
-V-VSS
vvidid
InvertingInverting
NoninvertingNoninverting
OutputOutput
++
__ii(-)(-)
ii(+)(+)
vvOO = A = Addvvidid
RROO
AARRii
Open-loop gain
Exercise 2.2
Analysis of Circuits Containing Ideal OP-AMPS
The Inverting Configuration
The inverting closed-loop configuration.
Closed-Loop Gain
Virtual Short-Circuit
Virtual Ground
Negative and Positive Feedback
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
vI
vo
A
R1
vI
vo
A
R1
vo
vo
Ai1 R2
vo
A
vI
vo
A
R1
R2
Gvo
vI
R2
R1
1
1R2
R1
A
Analysis of Circuits Containing Ideal OP-AMPS
Exercise 2.1
Analysis of Circuits Containing Ideal OP-AMPS
Input and Output Resistances
Ri
vI
iI
vI
vI
R1
R1
Ro 0
Analysis of Circuits Containing Ideal OP-AMPS
Exercise 2.2
Other Applications of the Inverting Configuration
With General Impedances
R2
+
R1
vo
is
v s
Z1
Z2
Other Applications of the Inverting Configuration
The Integrator
+ vo
ic
i -
R
vs
is
C vo t( )1
C R0
t
tvI t( )
d
Vo
VI
1s C R
Other Applications of the Inverting Configuration
PSpice Simulation Tips
Other Applications of the Inverting Configuration
The Differentiator
R2
+
R1
vo
is
v s
Z1 = 1/sC
Z2 = R
Other Applications of the Inverting Configuration
The Weighted Summer
Other Applications of the Inverting Configuration
The Non-Inverting Configuration
vi
v2 v1vo
AA infinite
vo vI
vI
R1R2
vo
vI1
R2
R1
Other Applications of the Inverting Configuration
The Voltage Follower
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
Finding the input resistance of the difference amplifier.
Other Applications of the Inverting Configuration
The Difference Amplifier – Input Resistances
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
The Difference Amplifier – Common-Mode and DifferentialComponents of the input signal
(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.
Other Applications of the Inverting Configuration
Instrumentation Amplifier
Open-loop gain of a typical general-purpose internally compensated op amp.
Effect Of Finite Open-Loop Gain and Bandwidth On Circuit Performance
fb = 3-db or break frequencyft = 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.