AD9280
V*
+FS
–FS
AIN
SHA
10k
10k
A2
10k
–F/S RANGE
OBTAINED FROM
VREF PIN OR
EXTERNAL REF
10k
REFBF
A/D
CORE
4.2k
TOTAL
0.1 F
10 F
MIDSCALE
AIN
SHA
AD9280
MODE
AVDD/2
0.1 F
AD9280
+F/S RANGE
OBTAINED FROM
VREF PIN OR
EXTERNAL REF
REFTS
REFBS
MODE
(AVDD)
REFTF
0.1 F
REFTS
10k
10k
REFTF
A2
REFBS
10k
INTERNAL
REF
10k
A/D
CORE
4.2k
TOTAL
0.1 F
10 F
0.1 F
REFBF
0.1 F
MIDSCALE OFFSET
VOLTAGE IS DERIVED
FROM INTERNAL OR
EXTERNAL REF
* MAXIMUM MAGNITUDE OF V IS DETERMINED
BY INTERNAL REFERENCE
a. Top/Bottom Mode
MAXIMUM MAGNITUDE OF V
IS DETERMINED BY INTERNAL
REFERENCE AND TURNS RATIO
V
AIN
AVDD/2
10k
10k
REFTS
REFBS
10k
INTERNAL
REF
10k
A2
A/D
CORE
4.2k
TOTAL
b. Center Span Mode
AD9280
SHA
MODE
AVDD/2
0.1 F
REFTF
0.1 F
10 F
0.1 F
REFBF
c. Differential Mode
VREF
(2V)
A1
1V
VREF
(1V)
1V
0.1 F
REFSENSE
1.0 F
A1
10k
REFSENSE
0.1 F
1.0 F
AD9280
AVSS
AD9280
10k
AVSS
d. 1 V Reference
e. 2 V Reference
A1
1V
VREF
(= 1 + R
A
/R
B
)
R
A
REFSENSE
R
B
0.1 F
1.0 F
A1
1V
REFSENSE
AVDD
VREF
AD9280
INTERNAL 10K REF RESISTORS ARE
SWITCHED OPEN BY THE PRESENSE
OF R
A
AND R
B
.
AVSS
AD9280
f. Variable Reference
(Between 1 V and 2 V)
g. Internal Reference Disable
(Power Reduction)
Figure 16.
–10–
REV. D
AD [ ANALOG DEVICES ]
