![](http://datasheet.mmic.net.cn/Analog-Devices-Inc/AD7709ARU_datasheet_100413/AD7709ARU_16.png)
REV. A
AD7709
–16–
Table VII. Configuration Register Bit Designations
Bit
Location
Name
Description
CONFIG23
PSW2
Power Switch 2 Control Bit.
Set by user to enable power switch SW2/P2 to PWRGND.
Cleared by user to enable use as a standard I/O pin. When the ADC is in standby mode, the power switches
are open.
CONFIG22
PSW1
Power Switch 1 Control Bit.
Set by user to enable power switch SW1/P1 to PWRGND.
Cleared by user to enable use as a standard I/O pin. When the ADC is in standby mode, the power switches
are open.
CONFIG21
I3EN1
IEXC3 Current Source Enable Bit
CONFIG20
I3EN0
IEXC3 Current Source Enable Bit
CONFIG19
I2EN1
IEXC2 Current Source Enable Bit
CONFIG18
I2EN0
IEXC2 Current Source Enable Bit
CONFIG17
I1EN1
IEXC1 Current Source Enable Bit
Configuration Register (A1, A0 = 0, 1; Power-On-Reset = 000007H)
The Configuration Register is a 24-bit register from which data can either be read or to which data can be written. This register is used to
select the input channel and configure the input range, excitation current sources, and I/O port. Table VII outlines the bit designations
for this register. CONFIG23 to CONFIG0 indicate the bit location, CONFIG denoting the bits are in the Configuration Register.
CONFIG23 denotes the first bit of the data stream. The number in brackets indicates the power-on-reset default status of that bit. A
write to the Configuration Register has immediate effect and does not reset the ADC. Therefore, if a current source is switched
while the ADC is converting, the user will have to wait for the full settling time of the sinc
3 filter before obtaining a fully settled output.
This equates to three outputs.
7
G
I
F
N
O
C7
G
I
F
N
O
C
7
G
I
F
N
O
C
7
G
I
F
N
O
C7
G
I
F
N
O
C6
G
I
F
N
O
C6
G
I
F
N
O
C
6
G
I
F
N
O
C
6
G
I
F
N
O
C6
G
I
F
N
O
C5
G
I
F
N
O
C5
G
I
F
N
O
C
5
G
I
F
N
O
C
5
G
I
F
N
O
C5
G
I
F
N
O
C4
G
I
F
N
O
C4
G
I
F
N
O
C
4
G
I
F
N
O
C
4
G
I
F
N
O
C4
G
I
F
N
O
C3
G
I
F
N
O
C3
G
I
F
N
O
C
3
G
I
F
N
O
C
3
G
I
F
N
O
C3
G
I
F
N
O
C2
G
I
F
N
O
C2
G
I
F
N
O
C
2
G
I
F
N
O
C
2
G
I
F
N
O
C2
G
I
F
N
O
C1
G
I
F
N
O
C1
G
I
F
N
O
C
1
G
I
F
N
O
C
1
G
I
F
N
O
C1
G
I
F
N
O
C0
G
I
F
N
O
C0
G
I
F
N
O
C
0
G
I
F
N
O
C
0
G
I
F
N
O
C0
G
I
F
N
O
C
)
0
(
L
E
S
F
E
R)
0
(
L
E
S
F
E
R
)
0
(
L
E
S
F
E
R
)
0
(
L
E
S
F
E
R)
0
(
L
E
S
F
E
R)
0
(
2
H
C)
0
(
2
H
C
)
0
(
2
H
C
)
0
(
2
H
C)
0
(
2
H
C)
0
(
1
H
C)
0
(
1
H
C
)
0
(
1
H
C
)
0
(
1
H
C)
0
(
1
H
C)
0
(
0
H
C)
0
(
0
H
C
)
0
(
0
H
C
)
0
(
0
H
C)
0
(
0
H
C)
0
(
I
N
U)
1
(
2
N
R)
1
(
1
N
R)
1
(
0
N
R
3
2
G
I
F
N
O
C3
2
G
I
F
N
O
C
3
2
G
I
F
N
O
C
3
2
G
I
F
N
O
C3
2
G
I
F
N
O
C2
2
G
I
F
N
O
C2
2
G
I
F
N
O
C
2
G
I
F
N
O
C
2
G
I
F
N
O
C2
2
G
I
F
N
O
C1
2
G
I
F
N
O
C1
2
G
I
F
N
O
C
1
2
G
I
F
N
O
C
1
2
G
I
F
N
O
C1
2
G
I
F
N
O
C0
2
G
I
F
N
O
C0
2
G
I
F
N
O
C
0
2
G
I
F
N
O
C
0
2
G
I
F
N
O
C0
2
G
I
F
N
O
C9
1
G
I
F
N
O
C9
1
G
I
F
N
O
C
9
1
G
I
F
N
O
C
9
1
G
I
F
N
O
C9
1
G
I
F
N
O
C8
1
G
I
F
N
O
C8
1
G
I
F
N
O
C
8
1
G
I
F
N
O
C
8
1
G
I
F
N
O
C8
1
G
I
F
N
O
C7
1
G
I
F
N
O
C7
1
G
I
F
N
O
C
7
1
G
I
F
N
O
C
7
1
G
I
F
N
O
C7
1
G
I
F
N
O
C6
1
G
I
F
N
O
C6
1
G
I
F
N
O
C
6
1
G
I
F
N
O
C
6
1
G
I
F
N
O
C6
1
G
I
F
N
O
C
)
0
(
2
W
S
P)
0
(
2
W
S
P
)
0
(
2
W
S
P
)
0
(
2
W
S
P)
0
(
2
W
S
P)
0
(
1
W
S
P)
0
(
1
W
S
P
)
0
(
1
W
S
P
)
0
(
1
W
S
P)
0
(
1
W
S
P)
0
(
1
N
E
3
I)
0
(
1
N
E
3
I
)
0
(
1
N
E
3
I
)
0
(
1
N
E
3
I)
0
(
1
N
E
3
I)
0
(
0
N
E
3
I)
0
(
0
N
E
3
I
)
0
(
0
N
E
3
I
)
0
(
0
N
E
3
I)
0
(
0
N
E
3
I)
0
(
1
N
E
2
I)
0
(
1
N
E
2
)
0
(
1
N
E
2
I
)
0
(
1
N
E
2
I)
0
(
1
N
E
2
I)
0
(
0
N
E
2
I)
0
(
0
N
E
2
I
)
0
(
0
N
E
2
I
)
0
(
0
N
E
2
I)
0
(
0
N
E
2
I)
0
(
1
N
E
1
I)
0
(
1
N
E
1
I
)
0
(
1
N
E
1
I
)
0
(
1
N
E
1
I)
0
(
1
N
E
1
I)
0
(
0
N
E
1
I)
0
(
0
N
E
1
I
)
0
(
0
N
E
1
I
)
0
(
0
N
E
1
I)
0
(
0
N
E
1
I
I2EN1
I2EN0
Function
00
IEXC2 Current Source OFF
01
IEXC2 Current Source Routed to the IOUT1 Pin
10
IEXC2 Current Source Routed to the IOUT2 Pin
11
Reserved
I3EN1
I3EN0
Function
00
IEXC3 Current Source OFF
01
IEXC3 Current Source Routed to the IOUT1 Pin
10
IEXC3 Current Source Routed to the IOUT2 Pin
11
Reserved
5
1
G
I
F
N
O
C4
1
G
I
F
N
O
C3
1
G
I
F
N
O
C2
1
G
I
F
N
O
C1
1
G
I
F
N
O
C0
1
G
I
F
N
O
C9
G
I
F
N
O
C8
G
I
F
N
O
C
)
0
(
G
I
D
4
P)
0
(
G
I
D
3
P)
0
(
N
E
2
P)
0
(
N
E
1
P)
0
(
T
A
D
4
P)
0
(
T
A
D
3
P)
0
(
T
A
D
2
P)
0
(
T
A
D
1
P