THS6007 Datasheet, PDF (33/36 Pages) Texas Instruments – DUAL DIFFERENTIAL LINE DRIVERS AND LOW-POWER RECEIVERS

THS6007
DUAL DIFFERENTIAL LINE DRIVERS AND LOW-POWER RECEIVERS
APPLICATION INFORMATION
SLOS334– DECEMBER 2000
general configurations (continued)
THS6007 driver amplifiers can also be used as very good video distribution amplifiers. One characteristic of
distribution amplifiers is the fact that the differential phase (DP) and the differential gain (DG) are compromised
as the number of lines increases and the closed-loop gain increases. Be sure to use termination resistors
throughout the distribution system to minimize reflections and capacitive loading.
620 Ω
620 Ω
75 Ω Transmission Line
–
75 Ω
VI
+
VO1
THS6007
75 Ω
N Lines
75 Ω
75 Ω
75 Ω
VON
Figure 90. Video Distribution Amplifier Application
driving a capacitive load
Driving capacitive loads with high performance amplifiers is not a problem as long as certain precautions are
taken. The first is to realize that the THS6007 has been internally compensated to maximize its bandwidth and
slew rate performance. When the amplifier is compensated in this manner, capacitive loading directly on the
output will decrease the device’s phase margin leading to high frequency ringing or oscillations. Therefore, for
capacitive loads of greater than 10 pF, it is recommended that a resistor be placed in series with the output of
the amplifier, as shown in Figure 91. A minimum value of 20 Ω should work well for most applications. For
example, in 75-Ω transmission systems, setting the series resistor value to 75 Ω both isolates any capacitance
loading and provides the proper line impedance matching at the source end.
1.3 kΩ
Input
1.3 kΩ
_
THS6007
Receiver
+
20 Ω
Output
CLOAD
Figure 91. Driving a Capacitive Load
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