Transcript Chap2

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
Exercise 2.1
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
Example 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
Example 2.2
Analysis of Circuits Containing Ideal OP-AMPS
Exercises
Other Applications of the Inverting Configuration
With General Impedances
Other Applications of the Inverting Configuration
Example 2.3
A difference amplifier.
Applications of superposition to the analysis of the current circuit of Fig.. 2.21.
Finding the input resistance of the difference amplifier.
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.
(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.
Open-loop gain of a typical general-purpose internally compensated op amp.
(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.