Datasheet

AD626
–11–
CURRENT SENSOR INTERFACE
A typical current sensing application, making use of the large
common-mode range of the AD626, is shown in Figure 9. The
cur rent being measured is sensed across resistor R
S
. The value of
R
S
should be less than 1 k⍀ and should be selected so that the
average differential voltage across this resistor is typically 100 mV.
To produce a full-scale output of +4 V, a gain of 40 is used adjust-
able by ±20% to absorb the tolerance in the sense re sis tor. Note
that there is suffi cient headroom to allow at least a 10% over range
(to +4.4 V).
R
G
R
H
CF
OPTIONAL
LOW-PASS
FILTER
OUTPUT
+V
S
CURRENT IN
C
URRENT OUT
0.1␮F
1
2
3
4
8
7
6
5
–IN
+IN
G = 100
OUT
AD626
200k⍀ 200k⍀
100k⍀
ANALOG
GND
–V
S
FILTER
1/6
+V
S
0.1␮F
–V
S
R
S
CURRENT
SENSOR
G = 2
G = 30
Figure 9. Current Sensor Interface
BRIDGE APPLICATION
Figure 10 shows the AD626 in a typical bridge application. Here,
the AD626 is set to operate at a gain of 100, using dual-sup ply
voltages and offering the option of low-pass fi ltering.
CF
OPTIONAL
LOW-PASS
FILTER
OUTPUT
+5V
0.1␮F
1
2
3
4
8
7
6
5
–IN
+IN
G = 100
OUT
AD626
200k⍀ 200k⍀
100k⍀
ANALOG
GND
–V
S
FILTER
1/6
+V
S
0.1␮F
–5V
+V
S
G = 30
G = 2
Figure 10. A Typical Bridge Application
REV. D