Datasheet

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  ±     
SLOS264G − MARCH 2000 − REVISED DECEMBER 2001
29
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
APPLICATION INFORMATION
general configurations (continued)
If a multiple pole filter is required, the use of a Sallen-Key filter can work very well with CFB amplifiers. This is
because the filtering elements are not in the negative feedback loop and stability is not compromised. Because
of their high slew-rates and high bandwidths, CFB amplifiers can create very accurate signals and help minimize
distortion. An example is shown in Figure 51.
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
Figure 51. 2-Pole Low-Pass Sallen-Key Filter