®

REF102

8

See AB-005 for more details.

FIGURE 9.

±10V Reference.

FIGURE 8. Strain Gauge Conditioner for 350

Ω Bridge.

I

R

See AB-002 for more details and I Sink Circuit.

R

1

= V

CC

– 10V

I

L (TYP)

a) –20mA < I

L

< +20mA

(OPA27 also improves transient immunity)

c) I

L (MAX)

= I

L (TYP)

+10mA

I

L (MIN)

= I

L (TYP)

–5mA

b) –5mA < I

FIGURE 7. +10V Reference With Output Current Boosted to: a)

±20mA, b) +100mA, and c) I

Ω

–

+

OPA27

6

220

+10V

I

L

6

+10V

I

L

2N2905

6

+10V

I

L

4

REF102

V+

2

4

REF102

V+

2

4

REF102

V+

2

–

+

INA101

V

x100

2

4

6

+15V

–5V

–15V

357

1/2W

Ω

2

3

OPA27

–

+

357

1/2W

Ω

28mA

28.5mA

+5V

350

Strain

Gauge Bridge

Ω

5

10

8

R

G

OUT

6

REF102

V+

REF102

6

4

2

3

1

25k

Ω

25k

Ω

25k

Ω

25k

Ω

INA105

5

6

+10V

Out

–10V

Out

2

–

+

LOAD

I

OUT

Can be connected

to ground or –V .

S

V+

REF102

2

6

4

OPA111

R

FIGURE 10. Positive Precision Current Source.