AD526

REV. D

–10–

GROUNDING AND BYPASSING

Proper signal and grounding techniques must be applied in

board layout so that specified performance levels of precision

data acquisition components, such as the AD526, are not

degraded.

As is shown in Figure 37, logic and signal grounds should be

separate. By connecting the signal source ground locally to the

AD526 analog ground Pins 5 and 6, gain accuracy of the

AD526 is maintained. This ground connection should not be

corrupted by currents associated with other elements within the

system.

GAIN

NETWORK

LATCHES AND LOGIC

DIGITAL

GROUND

AMP

FORCE

SENSE

ANALOG

GROUND 1

ANALOG

GROUND 2

AD526

+15V

–15V

0.1 F

0.1 F

0.1 F

0.1 F

1 F

+5V

AD574

12-BIT

A/D

CONVERTER

Figure 37. Grounding and Bypassing

OUT

FORCE

OUT

SENSE

0.1 F

0.1 F

+5V

A2

A1

A0

CLK

16

15

14

13

12

11

10

9

12

34

56

78

+

–

AD526

16

84

21

GAIN NETWORK

A1

A0

CS CLK

A2

B

LOGIC AND LATCHES

OUT

FORCE

OUT

SENSE

0.1 F

0.1 F

+5V

16

15

14

13

12

11

10

9

12

34

56

78

+

–

AD526

16

84

21

GAIN NETWORK

A1

A0

CS CLK

A2

B

LOGIC AND LATCHES

Figure 38. Cascaded Operation

Utilizing the force and sense outputs of the AD526, as shown in

Figure 38, avoids signal drops along etch runs to low impedance

loads.

Table II. Logic Table for Figure 38

A2

A1

A0

10

0

0

20

0

1

40

1

0

80

1

1

16

1

0

0

32

1

0

1

64

1

1

0

128

1

1

1