Datasheet

V
I
V
O
C1
+
R
G
R
F
R1
f
–3dB
1
2pR1C1
V
O
V
I
1
R
F
R
G
1
1 sR1C1
=
(
+
)( )
+
=
V
I
C2
R2R1
C1
R
F
R
G
R1 = R2 = R
C1 = C2 = C
Q = Peaking Factor
(Butterworth Q = 0.707)
(
=
1
Q
2
)
R
G
R
F
_
+
f
–3dB
1
2pRC
–
=
TLC080 , TLC081, TLC082
TLC083, TLC084, TLC085, TLC08xA
SLOS254F –JUNE 1999–REVISED DECEMBER 2011 www.ti.com
General Configurations
When receiving low-level signals, limiting the bandwidth of the incoming signals into theFigure 50 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 50. 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.
Figure 51. 2-Pole Low-Pass Sallen-Key Filter
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