Datasheet

11
ISO120/121
APPLICATIONS
The ISO120 and ISO121 isolation amplifiers are used in
three categories of applications:
1. Accurate isolation of signals from high voltage ground
potentials,
APPLICATION CIRCUITS
FIGURE 7. Eight-channel Isolated 0-20mA Loop Driver.
23
4
3
22
21
24
9
12
11
10
PWS740-3
PWS740-1
T
O
T
O
6
4
0.3µF
4
5
6
3
2
1
6
3
1
4
0.3µF
0.3µF
PWS740-2
0.3µF
10µF
+15V
+'E
20µH
1.0µF
–V
S1
To other 
channels
20kΩ
20pF
1.0µF
–15V
1.0µF
R
L
≤ 600Ω
I
L
= 0-20mA
VN2222
1/4W
250Ω
0.1%
6.2V
400mW
–15V
+15V
20kΩ
ISO120
1.0µF
0-5V
System Uses:
1 - Oscillator/Driver
8 - Transformers
8 - Bridges
8 - ISO120s
8 - Transistors VN2222
8 - Zener Diodes, 6.2V, 400mW, 20%
Not all components shown.
8
+V
IN
35
+15V
15
16
2. Accurate isolation of signals from severe ground noise
and,
3. Fault protection from high voltages in analog measure-
ments.
Figures 7 through 12 show a variety of Application Circuits.