Op-Amp
1
 Introduction of Operation Amplifier (Op-Amp)
 Analysis of ideal Op-Amp applications
 Comparison of ideal and non-ideal Op-Amp
 Non-ideal Op-Amp consideration
Operational Amplifier
Ref:080114HKN
Operational Amplifier
(Op-Amp)
2
 Very high differential





+V
cc
Input 1
gain
+
Vo
High input impedance
Vd
Output
Low output impedance

Input 2
Provide voltage changes
(amplitude and polarity) Rin~inf
-Vcc Rout~0
Used in oscillator, filter
Vo  GdVd
and instrumentation
Accumulate a very high Gd : differential gain normally
gain by multiple stages
5
very large, say 10
Operational Amplifier
Ref:080114HKN
IC Product
3
OFFSET
NULL
1
8
N.C.
-IN
2
7
V+
+IN
3
6
OUTPUT
V
4
5
OFFSET
NULL

+
DIP-741
Operational Amplifier
OUTPUT A
1
-IN A
2
+IN A
3
V
4
8 V+
7 OUTPUT B

+
-IN B

6
+
5 +IN B
Dual op-amp 1458 device
Ref:080114HKN
Single-Ended
Input
4
+
~ Vi
V
o

+
V
o

~
• + terminal : Source
• – terminal : Ground
• 0o phase change
• + terminal : Ground
• – terminal : Source
• 180o phase change
V
Operational Amplifier
i
Ref:080114HKN
Double-Ended
Input
5
V
+
d
~
• Differential input
V
•
o

+
~ V1
between Vo and Vd
V
o
Qu: What Vo should be if,
V
2

~
V  V V
d
 change

• 0o phase
shift
V
2
V
1
Ans: (A or B) ?
(A)
Operational Amplifier
(B)
Ref:080114HKN