ADS7864
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SBAS141A–SEPTEMBER 2000–REVISED MARCH 2005
+IN
CM +VREF
+VREF
CM Voltage
−
IN = CM Voltage
−
VREF
t
−
CM VREF
Single−Ended Inputs
+IN
+VREF
CM +1/2VREF
CM Voltage
−
VREF
−
IN
t
−
CM 1/2VREF
Differential Inputs
−
−
(IN+) (IN )
−
, Common−Mode Voltage (Single−Ended Mode) = IN .
NOTES: Common−Mode Voltage (Differential Mode) =
2
−
The maximum differential voltage between +IN and IN of the ADS7864 is VREF. See Figures 21 and 22 for a further
explanation of the common voltage range for single−ended and differential inputs.
Figure 20. Using the ADS7864 in the Single-Ended and Differential Input Modes
5
4
3
2
1
0
5
VCC = 5V
4.7
VCC = 5V
4.1
4
3
2
1
0
4.05
2.7
2.3
Single−Ended Input
Differential Input
0.90
0.9
0.3
−
1
−
1
1.2
2.6
2.5
1.2
2.6
2.5
1.0
1.5
2.0
3.0
1.0
1.5
2.0
VREF (V)
3.0
VREF (V)
Figure 21. Single-Ended Input: Common-Mode Voltage
Range vs VREF
Figure 22. Differential Input: Common-Mode
Voltage Range vs VREF
12
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