clc4600iso14x Cadeka Microcircuits LLC., clc4600iso14x Datasheet - Page 10
clc4600iso14x
Manufacturer Part Number
clc4600iso14x
Description
Dual, Triple, And Quad 300mhz Amplifers
Manufacturer
Cadeka Microcircuits LLC.
Datasheet
1.CLC4600ISO14X.pdf
(15 pages)
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Data Sheet
Application Information
Basic Operation
Figures 3, 4, and 5 illustrate typical circuit configurations for
non-inverting, inverting, and unity gain topologies for dual
supply applications. They show the recommended bypass
capacitor values and overall closed loop gain equations.
©2004-2008 CADEKA Microcircuits LLC
Input
Input
Input
Figure 3. Typical Non-Inverting Gain Circuit
Figure 5. Typical Unity Gain (G=1) Circuit
Figure 4. Typical Inverting Gain Circuit
R
R
R
1
g
+
-
g
+V
-V
+
-
s
s
+V
-V
+
-
+V
-V
6.8μF
0.1μF
0.1μF
6.8μF
s
s
s
s
0.1μF
6.8μF
6.8μF
0.1μF
6.8μF
0.1μF
0.1μF
6.8μF
R
f
G = 1
R
f
is required for CFB amplifiers
R
R
f
G = - (R
For optimum input offset
voltage set R
f
G = 1 + (R
R
L
Output
R
f
/R
L
R
g
Output
)
L
1
f
/R
= R
Output
g
f
)
|| R
g
CFB amplifiers can be used in unity gain configurations.
Do not use the traditional voltage follower circuit, where
the output is tied directly to the inverting input. With a
CFB amplifier, a feedback resistor of appropriate value
must be used to prevent unstable behavior. Refer to fig-
ure 5 and Table 1. Although this seems cumbersome, it
does allow a degree of freedom to adjust the passband
characteristics.
Feedback Resistor Selection
One of the key design considerations when using a CFB
amplifier is the selection of the feedback resistor, R
used in conjunction with R
tional non-inverting and inverting circuit configurations.
Refer to figures 3 and 4. As discussed in the Current Feed-
back Technology section, the value of the feedback resis-
tor has a pronounced effect on the frequency response of
the circuit.
Table 1, provides recommended R
ues for various gain settings. These values produce the
optimum frequency response, maximum bandwidth with
minimum peaking. Adjust these values to optimize perfor-
mance for a specific application. The typical performance
characteristics section includes plots that illustrate how
the bandwidth is directly affected by the value of R
various gain settings.
In general, lowering the value of R
mended value will extend the bandwidth at the expense
of additional high frequency gain peaking. This will cause
increased overshoot and ringing in the pulse response
characteristics. Reducing R
cause oscillatory behavior.
Increasing the value of Rf will lower the bandwidth. Low-
ering the bandwidth creates a flatter frequency response
and improves 0.1dB bandwidth performance. This is im-
portant in applications such as video. Further increase in
Rf will cause premature gain rolloff and adversely affect
gain flatness.
Gain
(V/V
1
2
5
Table 1: Recommended R
R
1240
510
200
f
(Ω)
R
510
g
50
-
(Ω)
g
f
to set the gain in the tradi-
±0.1dB BW
too much will eventually
(MHz)
129
140
18
f
and associated R
f
vs. Gain
f
www.cadeka.com
from the recom-
-3dB BW
(MHz)
300
230
111
f
. R
g
val-
f
f
10
at
is