Datasheet

FDS 6531/6532 005 Data Sheet 71M6531D/F-71M6532D/F
Rev 2 63
3 Application Information
3.1 Connection of Sensors
Figure 28 through Figure 30 show how resistive dividers, current transformers, Rogowski coils and resistive
shunts are connected to the voltage and current inputs of the 71M6531.
The analog input pins of the 71M65XX are designed for sensors with low source impedance. RC
filters with resistance values higher than those implemented in the Demo Boards should be avoided.
See Application Note AN5292 for details on filter implementation.
Figure 28: Resistive Voltage Divider
Figure 29: CT with Single Ended (Left) and Differential Input (Right) Connection
Figure 30: Resistive Shunt (Left) and Rogowski Sensor (Right) Connection
Note: Ferrites or other inductive components must not be connected directly to the sensor input pins (InP,
InN, Vn).
3.2 Connecting 5-V Devices
All digital input pins of the 71M6531D/F and 71M6532D/F are compatible with external 5-V devices. I/O
pins configured as inputs do not require current-limiting resistors when they are connected to external 5 V
devices.
V
out
R
1/N
I
in
I
out
Filter
V3P3
IA
InP
InN
V3P3A
V
OUT
I
OUT
I
IN
R
1/N
V
DIFF
V
out
R
I
in
IA
V3P3
Vout = c*dI
in
/dt
V
out
1/N
I
in
IAN
IAP
V3P3A