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18
RC4200
PRODUCT SPECIFICATION
Limited Range, First Quadrant Applications
The following circuit has the advantage that cross-product
errors are due only to input offsets and nonlinearity error is
sightly error is slightly less for lower input currents.
The circuit also has no standby current to add to the noise
content, although the signal-to-noise ratio worsens at very
low input currents (1-5
m
A) due to the noise current of the
input stages.
The R
S
C
S
filter circuits are added to each input to improve
the stability for input currents below 50
m
A.
Caution!
The bandpass drops off significantly for lower currents
(<50
m
A) and non-symmetrical rise and fall times can cause
second harmonic distortion.
Thermal Symmetry
The scale factor is sensitive to temperature gradients across
the chip in the lateral direction. Where possible, the package
should be oriented such that forces generating temperature
gradients are located physically on the line of thermal sym-
metry. This will minimize scale-factor error due to thermal
gradients.
1
2
3
4
I2
VOS2
–VS
Output I3
I1
VOS1
GND
Thermal
Symmetry
Line
I4
8
7
6
5
65-0070
65-1867
RC4200
Multiplier
S
X
S
R1
100
-V
+V
S
-V
3
6
4
5
8
7
1
2
V
1/4
4156
R
100 V
50 mV
S
-V
S
+V
R2
100
m
0.1 F
S
-V
S
+V
m
0.1 F
R4
O
S
+V
S
-V
Z
V
Y
V
Inputs
Cs
Rs
I
1
R1
V
I
2
I
4
I
3
0.1 F
Rs
Cs
V
50 mV
50 mV
V ADJ
100 R4
Gain
Adj.
R
Output
V
O
V
OS3
m
O
R = 10K, C = 0.005 F
s
V V
V
Y
z
R R4
R1 R2
Where K =
m