clc1605 Cadeka Microcircuits LLC., clc1605 Datasheet - Page 15

• Manufacturer Part Number: clc1605
• Description: Single And Triple, 1.5ghz Amplifers
• Manufacturer: Cadeka Microcircuits LLC.

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.
©2007-2008 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 figure 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
non-inverting and inverting circuit configurations. Refer to
figures 3 and 4. As discussed in the Current Feedback
Technology section, the value of the feedback resistor has
a pronounced effect on the frequency response of the
circuit.
Table 1, provides recommended R
values for various gain settings. These values produce
the optimum frequency response, maximum bandwidth
with minimum peaking. Adjust these values to optimize
performance for a specific application. The typical
performance characteristics section includes plots that
illustrate how the bandwidth is directly affected by the
value of R
In general, lowering the value of R
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 R
Lowering the bandwidth creates a flatter frequency
response and improves 0.1dB bandwidth performance.
This is important in applications such as video. Further
increase in R
adversely affect gain flatness.
Gain
(V/V
10
1
2
5
f
Table 1: Recommended R
at various gain settings.
R
499
330
330
330
f
(Ω)
f
will cause premature gain rolloff and
R
82.5
330
g
33
-
(Ω)
g
to set the gain in the traditional
f
f
±0.1dB BW
will lower the bandwidth.
too much will eventually
(MHz)
167
120
f
66
38
from the recommended
f
f
vs. Gain
and associated R
www.cadeka.com
-3dB BW
(MHz)
1500
1200
385
245
f
. R
f
15
is
g