Datasheet

ADS1212, 1213
33
SBAS064A
FIGURE 32. Full Interface with a 68HC11 Microprocessor.
Isolation
The serial interface of the ADS1212/13 provides for simple
isolation methods. An example of an isolated four-wire
interface is shown in Figure 33. The ISO150 is used to
transmit the digital signals over the isolation barrier.
In addition, the digital outputs of the ADS1212/13 can, in
some cases, drive opto-isolators directly. Figures 34 and 35
show the voltage of the SDOUT pin versus source or sink
current under worst-case conditions. Worst-case conditions
for source current occur when the analog input differential
FIGURE 33. Isolated Four-Wire Interface.
ADS1212
A
IN
P
A
IN
N
AGND
V
BIAS
CS
DSYNC
X
IN
X
OUT
DGND
REF
IN
REF
OUT
AV
DD
MODE
DRDY
SDOUT
SDIO
SCLK
DV
DD
PB7
PB6
PB5
PB4
PB3
PB2
PB1
PB0
PE0
PE1
PE2
XIRQ
RESET
PC7
PC6
PC5
PC4
PC3
PC2
PC1
PC0
XTAL
68HC11
C
2
6pF
C
1
6pF
AGND
DGND
AV
DD
DV
DD
XTAL
AGND
1.0µF
R
2
10kΩ
R
1
10kΩ
ADS1212
A
IN
P
A
IN
N
AGND
V
BIAS
CS
DSYNC
X
IN
X
OUT
DGND
REF
IN
REF
OUT
AV
DD
MODE
DRDY
SDOUT
SDIO
SCLK
DV
DD
XTAL
C
2
6pF
C
1
6pF
V
DD1
AGND
DGND
DGND
AV
DD
V
DD1
ISO150
D
1A
R/T
1A
V
SA
G
B
R/T
1B
D
1B
D
2A
R/T
2A
G
A
V
SB
R/T
2B
D
2B
V
DD2
V
DD1
V
DD1
V
DD2
R
1
100Ω
DGND
GND
DGND
GND
SCLK
SD
IN
V
DD2
V
DD1
V
DD2
DGND
DGND
GND
SD
OUT
DRDY
ISO150
D
1A
R/T
1A
V
SA
G
B
R/T
1B
D
1B
D
2A
R/T
2A
G
A
V
SB
R/T
2B
D
2B
AGND
1.0µF