THS3115CPWP Datasheet, PDF (12/35 Pages) Texas Instruments – LOW-NOISE, HIGH-SPEED, CURRENT FEEDBACK AMPLIFIERS

THS3112
THS3115
SLOS385C – SEPTEMBER 2001 – REVISED SEPTEMBER 2010
Single-Supply Operation
The THS3115 and THS3112 have the capability to
operate from a single supply voltage ranging from 10
V to 30 V. When operating from a single power
supply, biasing the input and output at mid-supply
allows for the maximum output voltage swing. The
circuits in Figure 41 show inverting and noninverting
amplifiers configured for single-supply operation.
+V_S
50-W Source
V_I
R_T
49.9 W
+V_S/2
THS3115
R_F
750 W
49.9 W
50-W Load
R_G
750 W
+V_S/2
R_F
750 W
50-W Source
R_G
750 W
V_I
53.6 W
R_T
+V_S
THS3115
+V_S/2
+V_S/2
49.9 W
50-W Load
Figure 41. DC-Coupled, Single-Supply Operation
Video Distribution
The wide bandwidth, high slew rate, and high output
drive current of the THS3115 and THS3112 match
the demands for video distribution to deliver 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. Figure 42 illustrates a typical video
distribution amplifier application configuration.
750 W
750 W
+15 V
V_I
75 W _{-15 V}
www.ti.com
75 W
75-W Transmission Line
V_O(1)
n lines
75 W
75 W
V_O(n)
75 W
Figure 42. Video Distribution Amplifier
Application
Driving Capacitive Loads
Applications such as FET drivers and line drivers can
be highly capacitive and cause stability problems for
high-speed amplifiers.
Figure 43 through Figure 49 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 feedback path. See Figure 43 for
recommended resistor values versus capacitive load.
60
50
40
30
20
10
0
10
100
C_L - Capacitive Load (pF)
Figure 43. Recommended R_ISO vs Capacitive
Load
12
Submit Documentation Feedback
Copyright © 2001–2010, Texas Instruments Incorporated
Product Folder Link(s): THS3112 THS3115