THS4051 Datasheet, PDF (19/36 Pages) Texas Instruments – 70-MHz HIGH-SPEED AMPLIFIERS

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THS4051
THS4052
SLOS238D − MAY 1999 − REVISED AUGUST 2008
APPLICATION INFORMATION
GENERAL CONFIGURATIONS
When receiving low-level signals, limiting the bandwidth of the incoming signals into the system is often required. The
simplest way to accomplish this is to place an RC filter at the noninverting terminal of the amplifier (see Figure 49).
RG
RF
VI
R1
−
+
C1
f–3dB +
Figure 49. Single-Pole Low-Pass Filter
If even more attenuation is needed, a multiple pole filter is required. The Sallen-Key filter can be used for this task. For best
results, the amplifier should have a bandwidth that is 8 to 10 times the filter frequency bandwidth. Failure to do this can
result in phase shift of the amplifier.
C
VI
R1
R2
C2
RG
Figure 50. 2-Pole Low-Pass Sallen-Key Filter
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