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Op-Amp
Operational Amplifier
Non Inverting Amplifier
Inverting Amplifier
Adder (and Subtractor using an Inverter)
Differential Amplifier Integrator
Differentiator
Op-Ampname derives from early usage of these elements in
performing mathematical operat ionsin analog computers.
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Three Ways to Examine Op-Amp
Behavior
Consider as an Ideal Op-Amp
Component
Consider as a Feedback Model
and Examine Behavior
Perform Conventional CircuitAnalysis
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VE= VIN+- VIN-
VOUT= a * VE
VIN+
VIN-
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Ideal Op-Amp Model
VE= VIN+- VIN-
VOUT= a * VE
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Behavior of Feedback Model
of
Non Inverting Amplifier
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Behavior of Feedback Model
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Behavior of Feedback Model
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Behavior of Feedback Model
Summary
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Circuit Analysis Approach
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Circuit Analysis Approach
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Op-Amp
Operational Amplifier
Non Inverting Amplifier
Inverting Amplifier
Adder (and Subtractor using an Inverter)
Differential Amplifier Integrator
Differentiator
Op-Ampname derives from early usage of these elements in
performing mathematical operat ionsin analog computers.
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Differential Amplifier Circuit Analysis
a (V+- V-)
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Differential Amplifier Circuit Analysis
a (V+- V-)
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Differential Amplifier Circuit Analysis
a (V+- V-)
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Differential Amplifier Circuit Analysis
a (V+- V-)
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Differential Amplifier Circuit Analysis
a (V+- V-)
ZF/ ZG
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Common Mode Rejection
Ratio
vicm
v2
v1
vi1 vi2vid/ 2
vid/ 2
v2
v1
Original Inputs Model of inputs with common-
mode and differential-mode
components
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cmA
ACMRR
whereAis the differential
mode gain andAcm
is thecommon mode gain
dBA
ACMRR
cm
dB log20
Ideally: CMRR Typically: 60 dB CMRR120 dB
Common Mode Rejection Ratio
CMRR
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Assumes R2 = R4and R1 = R3
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Differential Amplifier Circuit Analysis
with Component Imbalance
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Differential Amplifier Circuit Analysis
with Component Imbalance
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Differential Amplifier Circuit Analysis
with Component Imbalance
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Differential Amplifier Circuit Analysis
with Component Imbalance
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Differential Amplifier Circuit Analysis
with Component Imbalance
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The Maximum Power Transfer Theoremsimply
states, the maximum amount of power will be
dissipated by a load resistance when that loadresistance is
equal to the Thevenin/Norton resistance
of the network supplying the power.
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To create the Thevenin Equivalent Circuit we need:1. Value of
the Thevenin Voltage Source
2. Value of the Thevenin Resistance
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Instrumentation Amplifier
121
2
3
4 21 vvR
R
R
Rvv refout -
-
vout
R3
v1
R2
R3
v2
R1
R2
R4
R4
vref
-
-
1
2
3
4
12
21R
R
R
R
vv
vvG
refout
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f
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Instrumentation Amplifier
ExampleBu rr-Brown INA118
Parameters: kRRkRRR G 6025 4321
- ININrefoout VvVvvVv 12 Ref
GIN
o
R
kVG
-
-
-
501
VV
Ref
IN
If RG 49.9,
G 150,000
49.91,003
Gain:
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Instrumentation Amp (cont.)A feedback network may also be
included with the instrumentation amplifier.
vout
R3
v1
R2
R3
vdiff = v2- v12R
1
R2
R4
R4
R
C
RCs
Gs
sV
sV
diff
out
1
v2
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