Datasheet

OPA277, OPA2277, OPA4277
10
SBOS079A
www.ti.com
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–∆RR+∆R
V
1
14
1
12
5V
11
13
I
REG
∼ 1mA
4
3
2
6
R
G
1250Ω
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
10kΩ
R
412Ω
1/2
OPA2277
V+
V–
Type J
25Ω
(G = 1 + = 50)
2R
F
R
50Ω
1kΩ
R
F
10kΩ
I
R1
V
LIN
R
CM
= 1250Ω
0.01µF
FIGURE 3. Load Cell Amplifier.
FIGURE 4. Thermocouple Low Offset, Low Drift Loop Measurement with Diode Cold Junction Compensation.