1000
900
800
700
600
500
400
300
200
100
0
0
25
50
75
100
125
150
175
T
S
– CASE TEMPERATURE – °C
R1
V
IN
-
PD1
A1
+
C1
LED
R3
PD2
PD2
V
CC
A) BASIC TOPOLOGY
I
PD1
PD1
P
S
OUTPUT POWER – mV
I
S
INPUT CURRENT – mA
R1
V
IN
+
A1
-
LED
R2
-
I
PD2
I
F
PD2
A2
+
V
OUT
R2
C2
-
A2
+
V
OUT
Figure 11. Thermal Derating Curve
Dependence of Safety Limiting Value
with Case Temperature per VDE 0884.
B) PRACTICAL CIRCUIT
Figure 12. Basic Isolation Amplifier.
V
CC
V
IN
-
+
-
V
OUT
+
A) POSITIVE INPUT
B) POSITIVE OUTPUT
V
IN
-
+
-
V
OUT
+
C) NEGATIVE INPUT
D) NEGATIVE OUTPUT
Figure 13. Unipolar Circuit Topologies.
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