Burr-Brown Corporation OPA2277, Manual

Page: 10 / 27

OPA277, OPA2277, OPA4277
10
SBOS079A
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R
1
V–
1/2
OPA2277
R
2
1/2
OPA2277
V
OUT
= (V
1
– V
2
)(1 + )
R
2
R
1
V+
V+
V–
R
2
For integrated solution see: INA126, INA2126 (dual)
INA125 (on-board reference)
INA122 (single-supply)
R
1
Load
Cell
R+
∆
R
V
2
R–
∆
R
R–
∆
R R+
∆
R
V
1
14
1
12
5V
11
13
I
REG
∼
1mA
4
3
2
6
R
G
1250
Ω
XTR105
1/2
OPA2277
7
R
G
R
G
V
IN
–
V
IN
+
V
REG
I
R2
V+
I
RET
I
O
E
B
8
I
O
= 4mA + (V
IN
– V
IN
)
+ –
40
R
G
9
10
R
F
10k
Ω
R
412
Ω
1/2
OPA2277
V+
V–
Type J
25
Ω
(G = 1 + = 50)
2R
F
R
50
Ω
1k
Ω
R
F
10k
Ω
I
R1
V
LIN
R
CM
= 1250
Ω
0.01µF
FIGURE 3. Load Cell Amplifier.
FIGURE 4. Thermocouple Low Offset, Low Drift Loop Measurement with Diode Cold Junction Compensation.