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Inductors And

Common Mode Chokes

For Use in ADSL POTS Low Pass Filters

B902.E (02/12)

Performance Description

Application Circuit

Frequency Response

For More Information

The following schematic depicts a typical LC filter that

incorporates the use of a common mode choke in addition

to the LC network. As shown in the frequency response

graph below, at low frequencies, the amplitude of the

output signal is roughly equal to the amplitude of the

input signal. At higher frequencies, the amplitude of the

output decreases. Thus, the network passes low frequency

voice signals with only a small degree of attenuation,

while it suppresses high frequency signals and acts as a

low pass filter.

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Performance warranty of products offered on this data sheet is limited to the parameters specified. Data is subject to change without notice. Other brand and product names mentioned herein may be

trademarks or registered trademarks of their respective owners. © Copyright, 2012. Pulse Electronics, Inc. All rights reserved.

The series of coupled inductors shown on this data sheet are current and temperature, high self-resonant frequency, low

ideal for use in Asymmetrical Digital Subscriber Line (ADSL) applications where a low pass filter is required to separate

the voice frequencies from the data frequencies that are carried on an ADSL line. In spite of their small footprint and low

profile, these coupled inductors provide excellent electrical performance. They have stable inductance with varying DC

current and temperature, high self-resonant frequency, low coupling capacitance, and excellent balance. The common

mode chokes were developed to reduce common mode voltages in the low frequency range that is used for voice

transmission. The chokes are also designed to accommodate DC currents up to 100 mA.

Choke

Inductor

Inductor

Inductor

Capacitor

Capacitor

Capacitor

Input

ADSL & POTS

Signals

Output

POTS Signal

Only

100 Hz

1 KHz10 KHz

100 KHz

B

d

0

F

E

R

/

B

d

0

1

-100 dB

0 dB