Datasheet

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SBOS266E − JUNE 2003 − REVISED AUGUST 2008
www.ti.com
15
OPA832
+5V
−
5V
V
OUT
50
Ω
V
IN
R
F
400
Ω
175
Ω
50
Ω
Source
150
Ω
R
G
400
Ω
6.8
µ
F
+
6.8
µ
F
+
0.1
µ
F
0.1
µ
F
0.01
µ
F
Figure 3. DC-Coupled, G = +2, Bipolar Supply
Specification and Test Circuit
DESIGN-IN TOOLS
DEMONSTRATION FIXTURES
Two printed circuit boards (PCBs) are available to assist
in the initial evaluation of circuit performance using the
OPA832 in its two package options. Both of these are
offered free of charge as unpopulated PCBs, delivered
with a user’s guide. The summary information for these
fixtures is shown in Table 1.
Table 1. Demonstration Fixtures by Package
ORDERING LITERATURE
PRODUCT PACKAGE
ORDERING
NUMBER
LITERATURE
NUMBER
OPA832ID SO-8
DEM-OPA-SO-1A
SBOU009
OPA832IDBV SOT23-5
DEM-OPA-SOT-1A
SBOU010
The demonstration fixtures can be requested at the
Texas Instruments web site (www.ti.com) through the
OPA832 product folder.
MACROMODEL AND APPLICATIONS
SUPPORT
Computer simulation of circuit performance using
SPICE is often a quick way to analyze the performance
of the OPA832 and its circuit designs. This is particularly
true for video and RF amplifier circuits where parasitic
capacitance and inductance can play a major role on
circuit performance. A SPICE model for the OPA832 is
available through the TI web page (www.ti.com). The
applications group is also available for design assis-
tance. These models predict typical small signal AC,
transient steps, DC performance, and noise under a
wide variety of operating conditions. The models in-
clude the noise terms found in the electrical specifica-
tions of the data sheet. These models do not attempt to
distinguish between the package types in their small-
signal AC performance.
GAIN OF +2V/V VIDEO LINE DRIVER
One of the most suitable applications for the OPA832
is a simple gain of +2 video line driver. Figure 4 shows
how simple this circuit is to implement, shown as a ±5V
implementation. Single +5V operation is similar with
blocking caps and DC common-mode biasing provided.
OPA832
Video
In
Video
Loads
+5V
−
5V
Optional 1.3k
Ω
Pull−Down
Figure 4. Gain of +2V/V Video Line Driver
One optional element is shown in Figure 4. A 1.3kΩ
pull-down to the negative supply will improve the differ-
ential phase significantly and the differential gain slight-
ly. Figure 5 shows measured dG/dP with and without
that pull-down resistor from 1 to 4 video loads.
1.2
1.0
0.8
0.6
0.4
0.2
0
Number of 150
Ω
Loads
dG/dP
1234
dG
dP
dG
dP
No Pull−Down
With 1.3k
Ω
Pull−Down
OPA832
Video
In
Video
Loads
+5V
−
5V
Optional 1.3k
Ω
Pull−Down
Figure 5. dG/dP vs Video Loads