ISL55004 Intersil Corporation, ISL55004 Datasheet - Page 12

• Manufacturer Part Number: ISL55004
• Description: (ISL55002 / ISL55004) High Supply Voltage 220MHz Unity-Gain Stable Operational Amplifiers
• Manufacturer: Intersil Corporation

Differential Output Instrumentation Amplifier
The addition of a third amplifier to the conventional three
amplifier instrumentation amplifier introduces the benefits of
differential signal realization, specifically the advantage of
using common-mode rejection to remove coupled noise and
ground potential errors inherent in remote transmission. This
configuration also provides enhanced bandwidth, wider
output swing and faster slew rate than conventional three
amplifier solutions with only the cost of an additional
amplifier and few resistors.
e
2
e
1
R
G
R
R
+
+
-
-
A
A
2
2
2
1
V
0V
5
R
+
R
-
3
3
R
R
3
1kΩ
VARIABLE SUBJECT
3
R
12
15
TO STRAIN
1kΩ
1kΩ
R
+
+
-
-
R
R
R
A
A
3
3
1kΩ
3
3
R
3
4
16
REF
+
-
e
e
e
o
o
o
3
4
ISL55002, ISL55004
R
R
17
18
1kΩ
1kΩ
1kΩ
BW
Strain Gauge
The strain gauge is an ideal application to take advantage of
the moderate bandwidth and high accuracy of the ISL55002
and ISL55004. The operation of the circuit is very
straightforward. As the strain variable component resistor in
the balanced bridge is subjected to increasing strain, its
resistance changes, resulting in an imbalance in the bridge.
A voltage variation from the referenced high accuracy
source is generated and translated to the difference amplifier
through the buffer stage. This voltage difference as a
function of the strain is converted into an output voltage.
R
e
e
F
o3
o
=
+
-
=
=
–
2f
----------------- -
–
2 1
+
-
V+
V-
+
-
A
(
(
C1 2
1nF
1nF
1
C
V
5V
V
5V
Di
C
12
2
4
+
6
+
,
2R
2R
2
2
⁄
⁄
R
R
A
G
G
Di
) e
) e
R
1kΩ
(
(
L
=
1
1
–
–
–
V
(V1+V2+V3+V4)
2 1
e
e
OUT
2
(
2
)
)
+
2R
e
o4
2
⁄
R
=
G
(
)
1
+
2R
2
⁄
R
G
July 15, 2005
) e
(
FN7497.1
1
–
e
2
)