THS6042, THS6043

350 mA, ±12 V ADSL CPE LINE DRIVERS

SLOS264G − MARCH 2000 − REVISED DECEMBER 2001

29

POST OFFICE BOX 655303

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.

VI

C2

R2

R1

C1

RF

RG

R1 = R2 = R

C1 = C2 = C

Q = Peaking Factor

(Butterworth Q = 0.707)

(

=

1

Q

2 −

)

RG

RF

_

+

f

–3dB +

1

2

pRC

Figure 51. 2-Pole Low-Pass Sallen-Key Filter