ISL55002_06 Datasheet, PDF (10/12 Pages) Intersil Corporation – High Supply Voltage 200MHz Unity-Gain Stable Operational Amplifier

ISL55002
R₁
V₁
1kΩ
C₁
1nF
R₂
1kΩ C₂
1nF
R_A
1kΩ
V₂
5V
C₅
1nF
+ ^V+
- _V-
R_B
1kΩ
C₅
1nF
V₃
5V
V_OUT
R₇
1kΩ
Holp = K
wo =
1
R1C1R2C2
Q=
1
(1− K) ^R1C1 + ^R1C2 +
R2C2 R2C1
R2C2
R1C1
Holp = ^K
4−K
wo = ²
RC
Equations simplify if we let
all components be equal R=C
Q= ²
4−K
FIGURE 29. SALLEN-KEY HIGH PASS FILTER
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.
A₁
e₁
+
-
R₂
R_G
R₃
R₃
R₃
R₃
A₃
-
e_o3
+
+
R₃
REF
R₃
e_o
e_o3 = –(1 + 2R₂ ⁄ R_G)(e₁ – e₂) e_o4 = (1 + 2R₂ ⁄ R_G)(e₁ – e₂)
e_o = –2(1 + 2R₂ ⁄ R_G)(e₁ – e₂)
BW = ²----^f--^C----¹---^,---²-
A_Di
A_Di = –2(1 + 2R₂ ⁄ R_G)
Strain Gauge
The strain gauge is an ideal application to take advantage of
the moderate bandwidth and high accuracy of the ISL55002.
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.
R₂
A₄
-
+
-
e_o4
A₂
-
R₃
R₃
e₂
+
FIGURE 30. DIFFERENTIAL OUTPUT AMPLIFIER
10
FN7497.4
July 27, 2006