6

Application Information

FIGURE 6. PRECISION WEIGHTED RESISTOR

PROGRAMMABLE GAIN AMPLIFIER

FIGURE 7. OPEN LOOP SAMPLE AND HOLD

V

OUT

V

IN

----------------

R

1

R

2

R

3

R

4

+++

R

4

-------------------------------------------------

100 with SW

==

+15V

-15V

FET INPUT

OP AMP

13

3

2

+15V

7

6

4k

Ω

5k

Ω

90k

Ω

3

14

11

6

GAIN ERROR IS DETERMINED ONLY BY THE RESISTOR TOLERANCE.

OP AMP OFFSET AND CMRR WILL LIMIT ACCURACY OF CIRCUIT.

2

1

15

16

10

9

7

8

V-

4

-15V

GND

5

1k

Ω

4

+

-

+

-

1

0

1/4 DG442

+15V

-15V

= SAMPLE

= HOLD

Typical Performance Curves

100

80

60

40

20

0

-20

0

20

±8V

±10V

±5V

±12V

±15V

±20V

80

70

60

50

40

30

20

10

0

-15

0

15

V+ = +15V

V- = -15V

DG441, DG442