1/4
OPA4131
INA141
RA
LA
1/4
OPA4131
20kΩ
390kΩ
1/4
OPA4131
390kΩ
10kΩ
V
G
20kΩ
Ref
V
O
G = 10
1/4
OPA4131
RL
FIGURE 4. ECG Amplifier With Right-Leg Drive.
+5V
2.5V –
∆V
INA141
Ref
2.5V +
∆V
Pt100
+15V
10.0V
6
REF102
2
V+
300Ω
V
O
R
1
R
2
4
–15V
K
Cu
Cu
INA141
R
3
100Ω = Pt100 at 0°C
Ref
V
O
FIGURE 5. Bridge Amplifier.
–
V
IN
+
INA141
Ref
C
1
0.1µF
V
O
R
1
1MΩ
ISA
TYPE
E
J
f
–3dB
=
1
2πR
1
C
1
MATERIAL
+ Chromel
– Constantan
+ Iron
– Constantan
+ Chromel
– Alumel
+ Copper
– Constantan
SEEBECK
COEFFICIENT
(
µ
V/
°
C)
58.5
50.2
39.4
38.0
R
1
, R
2
66.5kΩ
76.8kΩ
97.6kΩ
102kΩ
OPA602
K
T
= 1.59Hz
FIGURE 6. AC-Coupled Instrumentation Amplifier.
FIGURE 7. Thermocouple Amplifier With RTD Cold-
Junction Compensation.
–
V
IN
+
Ref
A
1
A
1
OPA177
OPA131
OPA602
OPA128
I
B
Error
±1.5nA
50pA
±1pA
±75fA
R
1
INA141
I
B
I
O
=
V
IN
•G
R
1
I
O
Load
®
FIGURE 8. Differential Voltage to Current Converter.
INA141
10
TI [ TEXAS INSTRUMENTS ]
