Datasheet

PACKAGE CONSIDERATIONS
3
0
-3
-6
-9
-12
Frequency(MHz)
NormalizedGain(dB)
0 50 100 200
A
VMAX
=2V/V
A
VMAX
=50V/V
A
VMAX
=100V/V
A
VMAX
=5V/V
A
VMAX
=10V/V
A
VMAX
=20V/V
150
50W
R
F
50W
V
G
V
IN
50W
Source
R
G
50W
Load
V
OUT
R
1
R
2
R
3
+V
IN
-V
IN
R
G-
R
G+
3
0
-3
-6
-9
-12
Frequency(MHz)
NormalizedGain(dB)
0 50 100 200
A =2V/V
VMAX
A =50V/V
VMAX
A =100V/V
VMAX
A =5V/V
VMAX
A =10V/V
VMAX
A =20V/V
VMAX
150
MAXIMUM GAIN OF OPERATION
I =
RG
V
OUT
A R´
V
MAX G
(8)
VCA822
SBOS343C – SEPTEMBER 2007 – REVISED DECEMBER 2008 ..................................................................................................................................... www.ti.com
The VCA822 is available in both SO-14 and
MSOP-10 packages. Each package has, for the
different gains used in the typical characteristics,
different values of R
F
and R
G
in order to achieve the
same performance detailed in the Electrical
Characteristics table.
Figure 88 shows a test gain circuit for the VCA822.
Table 3 lists the recommended configuration for the
SO-14 and MSOP-10 package.
Figure 89. SO-14 Recommended R
F
and R
G
versus A
VMAX
Figure 88. Test Circuit
Table 3. SO-14 and MSOP-10 R
F
and R
G
Configurations
G = 2 G = 10 G = 100
R
F
1.33k Ω 1k Ω 845 Ω
R
G
1.33k Ω 200 Ω 16.9 Ω
Figure 90. MSOP-10 Recommended R
F
and R
G
versus A
VMAX
There are no differences between the packages in
the recommended values for the gain and feedback
resistors. However, the bandwidth for the
VCA822IDGS (MSOP-10 package) is lower than the
This section describes the use of the VCA822 in a
bandwidth for the VCA822ID (SO-14 package). This
fixed-gain application in which the V
G
control pin is
difference is true for all gains, but especially true for
set at V
G
= +1V. The tradeoffs described here are
gains greater than 5V/V, as can be seen in Figure 89
with bandwidth, gain, and output voltage range.
and Figure 90 . Note that the scale must be changed
to a linear scale to view the details.
In the case of an application that does not make use
of the V
GAIN
, but requires some other characteristic of
the VCA822, the R
G
resistor must be set such that
the maximum current flowing through the resistance
I
RG
is less than ± 2.6mA typical, or 5.2mA
PP
as
defined in the Electrical Characteristics table, and
must follow Equation 8 .
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