AD526 Analog Devices, Inc., AD526 Datasheet - Page 10

• Manufacturer Part Number: AD526
• Description: Software Programmable Gain Amplifier
• Manufacturer: Analog Devices, Inc.

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.
AD526
V
IN
GROUND 1
ANALOG
AD526
Figure 37. Grounding and Bypassing
LATCHES AND LOGIC
GROUND 2
NETWORK
ANALOG
CLK
V
GAIN
A2
A1
A0
IN
A1
16
1
+15V
+V
AD526
16
LOGIC AND LATCHES
S
A0
0.1 F
15
AMP
2
GAIN NETWORK
8
14
CS CLK
3
0.1 F
GROUND
4
DIGITAL
FORCE
SENSE
13
4
–15V
V
V
–V
2
OUT
OUT
S
0.1 F
0.1 F
12
A2
5
1
+5V
11
B
6
+
–
–V
+V
10
7
Figure 38. Cascaded Operation
S
S
CONVERTER
0.1 F
AD574
12-BIT
9
8
0.1 F
A/D
1 F
OUT
FORCE
OUT
SENSE
+5V
–10–
Utilizing the force and sense outputs of the AD526, as shown in
Figure 38, avoids signal drops along etch runs to low impedance
loads.
16
A1
1
AD526
16
LOGIC AND LATCHES
A0
15
2
GAIN NETWORK
8
14
CS CLK
3
4
V
128
16
32
64
OUT
13
Table II. Logic Table for Figure 38
4
1
2
4
8
2
/V
A2
12
5
1
IN
+5V
11
B
6
+
–
A2
0
0
0
0
1
1
1
1
–V
+V
10
7
S
S
9
8
0.1 F
0.1 F
OUT
FORCE
OUT
SENSE
A1
0
0
1
1
0
0
1
1
V
A0
0
1
0
1
0
1
0
1
OUT
REV. D