Datasheet

50W
1kW
OPA695
V
OUT
1kW
OPA820
0.1 Fm
1N4150
V
REF
+V
IN
R
G+
R
G-
-V
IN
FB
V
G
200W
50W
50W
50W
100W
V
IN
50W
950W
VCA821
Out
DESIGN-IN TOOLS
DEMONSTRATION BOARDS
OPERATING SUGGESTIONS
MACROMODELS AND APPLICATIONS
VCA821
SBOS407B DECEMBER 2007 REVISED DECEMBER 2008 .......................................................................................................................................
www.ti.com
Figure 81. AGC Loop
predict typical small-signal ac performance, transient
steps, dc performance, and noise under a wide
variety of operating conditions. The models include
the noise terms found in the electrical specifications
of the relevant product data sheet.
Two printed circuit boards (PCBs) are available to
assist in the initial evaluation of circuit performance
using the VCA821 in its two package options. Both of
Operating the VCA821 optimally for a specific
these are offered free of charge as unpopulated
application requires trade-offs between bandwidth,
PCBs, delivered with a user's guide. The summary
input dynamic range and the maximum input voltage,
information for these fixtures is shown in Table 1 .
the maximum gain of operation and gain, output
dynamic range and the maximum input voltage, the
Table 1. EVM Ordering Information
package used, loading, and layout and bypass
LITERATURE
recommendations. The Typical Characteristics have
BOARD PART REQUEST
been defined to cover as much ground as possible to
PRODUCT PACKAGE NUMBER NUMBER
describe the VCA821 operation. There are four
VCA821ID SO-14 DEM-VCA-SO-1B SBOU050
sections in the Typical Characteristics :
VCA821IDGS MSOP-10 DEM-VCA-MSOP-1A SBOU051
V
S
= ± 5V DC Parameters and V
S
= ± 5V DC and
Power-Supply Parameters , which include dc
The demonstration fixtures can be requested at the
operation and the intrinsic limitation of a VCA821
Texas Instruments web site (www.ti.com ) through the
design
VCA821 product folder.
V
S
= ± 5V, A
VMAX
= 6dB Gain of 6dB Operation
V
S
= ± 5V, A
VMAX
= 20dB Gain of 20dB Operation
SUPPORT
V
S
= ± 5V, A
VMAX
= 32dB Gain of 32dB Operation
Computer simulation of circuit performance using
Where the Typical Characteristics describe the actual
SPICE is often useful when analyzing the
performance that can be achieved by using the
performance of analog circuits and systems. This
amplifier properly, the following sections describe in
principle is particularly true for video and RF amplifier
detail the trade-offs needed to achieve this level of
circuits where parasitic capacitance and inductance
performance.
can play a major role in circuit performance. A SPICE
model for the VCA821 is available through the TI web
page. The applications group is also available for
design assistance. The models available from TI
22 Submit Documentation Feedback Copyright © 2007 2008, Texas Instruments Incorporated
Product Folder Link(s): VCA821