THS3091 Datasheet, PDF (29/45 Pages) Texas Instruments – HIGH-VOLTAGE, LOW-DISTORTION, CURRENT-FEEDBACK OPERATIONAL AMPLIFIERS

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8 Application and Implementation
THS3091, THS3095
SLOS423H – SEPTEMBER 2003 – REVISED DECEMBER 2015
NOTE
Information in the following applications sections is not part of the TI component
specification, and TI does not warrant its accuracy or completeness. TI’s customers are
responsible for determining suitability of components for their purposes. Customers should
validate and test their design implementation to confirm system functionality.
8.1 Application Information
8.1.1 Video Distribution
The wide bandwidth, high slew rate, and high output drive current of the THS309x matches the demands for
video distribution for delivering video signals down multiple cables. To ensure high signal quality with minimal
degradation of performance, a 0.1-dB gain flatness should be at least 7x the passband frequency to minimize
group delay variations from the amplifier. A high slew rate minimizes distortion of the video signal, and supports
component video and RGB video signals that require fast transition times and fast settling times for high signal
quality.
1.21 kΩ 1.21 kΩ
15 V
−
75-Ω Transmission Line
75 Ω
V_O(1)
V_I
+
−15 V
75 Ω
n Lines
75 Ω
75 Ω
V_O(n)
75 Ω
Figure 63. Video Distribution Amplifier Application
8.1.2 Driving Capacitive Loads
Applications such as FET line drivers can be highly capacitive and cause stability problems for high-speed
amplifiers.
Figure 64 through Figure 69 show recommended methods for driving capacitive loads. The basic idea is to use a
resistor or ferrite chip to isolate the phase shift at high frequency caused by the capacitive load from the
amplifier’s feedback path. See SLOA013 for recommended resistor values versus capacitive load.
45
40
35
30
25
20
15
10
5
0
10
Gain = 5,
R_L = 100 Ω,
V_S = ±15 V
100
C_L − Capacitive Load − pF
Figure 64. Recommended R_ISO vs Capacitive Load
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Product Folder Links: THS3091 THS3095
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