Datasheet

AD7707
Rev. B | Page 44 of 52
AD420
DAC
CONTROL
ROOM
AD7707
DV
DD
+5V
AIN2
REF IN(–)
AGND
MCLK IN
MCLK OUT
REF IN(+)
AV
DD
AIN1
LOCOM
+2.5V
AIN3
VBIAS
HICOM
DGND
MICRO-
CONTROLLER
ACTUATOR/
VALVE
±10V
SMART
VALVE/ACTUATOR
RSENSE
0
8691-026
Figure 26. Smart Valve/Actuator Control Using the AD7707
REF IN(+)
REF IN(–)
4.7µF
100kΩ
MCLK IN
MCLK OUT
AD7707
V
CC
COM
V
CC
BOOST
REF OUT1
REF OUT2
REF IN
AD421
C1 C2 C3 COM
LOOP
RTN
COMP
DRIVE
4.7µF
0.01µF
0.1µF2.2µF
DN25D
1kΩ
1000pF
0.01µF
0.01µF
0.0033µF
SENSORS
RTD
mV
MAIN TRANSMITTER ASSEMBLY
AGND DGND
T
HERMOCOUPLE
V
AIN1
3V
1.25V
AIN2
AIN3
08691-027
MICROCONTROLLER UNIT
•PID
•RANGE SETTING
•CALIBRATION
•LINEARIZATION
•OUTPUT CONTROL
•SERIAL COMMUNICATION
•HART PROTOCOL
AV
DD
DV
DD
4mA
TO
20mA
Figure 27. Smart Transmitter Using the AD7707