9

OPA277, 2277, 4277

®

R

1

V–

1/2

OPA2277

R

2

1/2

OPA2277

V

)

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

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

+–

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

0.01µF

FIGURE 3. Load Cell Amplifier.

FIGURE 4. Thermocouple Low Offset, Low Drift Loop Measurement with Diode Cold Junction Compensation.