Analog Devices AD8556-EVALZ, User Manual

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AD8556-EVALZ/AD8556CP-EBZ User Guide UG-896
Rev. A | Page 7 of 9
In Figure 6, overall gain = 100 (G1 = default = 4, G2 = Code 1 =
25, offset = 2.5 V or Code 128).
T
1
2
[ ]
T
Ch1 Ch2 M A 50.0mV BW 2.00V BW Ch1 2.00mV 400ms
T 9.600%
11
88
6-
00
5
Figure 6. Output with Overall Gain = 100
In Figure 7, V
IN
= 2 mV p-p, G1 = 6.4, G2 = 35, and offset =
2.5 V or Code 128.
T
1
2
[ ]
T
Ch2 Ch1 M A 20.0mV BW 2.00V BW Ch1 –1.20mV 400ms
T 9.600%
11
886
-0
06
Figure 7. Output at V
IN
= 2 mV p-p, G1 = 6.4, G2 = 35, Offset = 2.5 V
OUTPUT CLAMP FEATURE
The output of the device can be clamped to the desired level.
The output clamp feature is provided to protect the circuitry
that follows the
AD8556-EVALZ , in case the input to AD8556-
EVALZ is accidentally larger than anticipated.
In normal situations (V
SUPPLIES
= ±2.5 V, gain = 70, V
OFFSET
= 2.5 V,
input = 40 mV p-p), the response to an input is as shown in
Figure 8.
T
2
1
[ ]
T
Ch1 Ch2 M A 20.0mV BW 2.00V BW Ch1 2.00mV 100ms
T 0.00000s
1
18
86-
00
7
Figure 8. Normal Response
Figure 9 shows the output after VCLAMP is set to 0.8 V.
T
2
1
[ ]
T
Ch1 Ch2 M A 20.0mV BW 2.00V BW Ch1 2.00mV 100ms
T 0.00000s
11
88
6
-0
08
Figure 9. Response with VCLAMP Set
Applying a large gain to an input yields saturation, as shown in
Figure 10. The conditions are V
IN
= 20 mV p-p, G1 = 6.4, G2 =
200, offset = 2.5 V.
T
1
2
[ ]
T
Ch2 Ch1 M A 20.0mV BW 2.00V BW Ch1 –1.20mV 400ms
T 9.600%
11
88
6-
00
9
Figure 10. Results with Saturation
Note that Resistor RT1 and Resistor RT2 are used for pulse
stretching; do not adjust them. They are factory-adjusted for
optimal results.