V+
+3V
3V
10.0V
6
REF102
2
2V – ∆V
R1
R2
VO
RG
INA118
4
300Ω
Ref
Pt100
2V + ∆V
Cu
Cu
150Ω
R1
K
(1)
VO
RG
INA118
Ref
R3
100Ω = RTD at 0°C
NOTE: (1) R1 required to create proper common-mode voltage,
only for low voltage operation — see text.
SEEBECK
ISA
COEFFICIENT
TYPE
MATERIAL
(µV/°C)
R1, R2
FIGURE 5. Single-Supply Bridge Amplifier.
E
+ Chromel
– Constantan
58.5
66.5kΩ
76.8kΩ
97.6kΩ
102kΩ
J
+ Iron
– Constantan
50.2
39.4
38.0
K
T
+ Chromel
– Alumel
+ Copper
– Constantan
–
VO
VIN
+
RG
INA118
Ref
FIGURE 7. Thermocouple Amplifier With Cold Junction
Compensation.
R1
C1
0.1µF
1MΩ
VIN
R1
–
R1
IO
=
• G
1
f–3dB
=
VIN
+
RG
INA118
Ref
2πR1C1
OPA602
= 1.59Hz
IB
A1
IO
Load
FIGURE 6. AC-Coupled Instrumentation Amplifier.
A1
IB Error
OPA177
OPA602
OPA128
±1.5nA
±1pA
±75fA
FIGURE 8. Differential Voltage to Current Converter.
2.8kΩ
VO
LA
RG/2
INA118
Ref
RA
2.8kΩ
G = 10
390kΩ
1/2
OPA2604
1/2
OPA2604
10kΩ
RL
390kΩ
FIGURE 9. ECG Amplifier With Right-Leg Drive.
®
11
INA118
TI [ TEXAS INSTRUMENTS ]
