2744040447 Fair-Rite, 2744040447 Datasheet - Page 180

• Manufacturer Part Number: 2744040447
• Description: 44 SM Ferrite Beads, T&R
• Manufacturer: Fair-Rite

Fair-Rite Products Corp.
Phone: (888) FAIR RITE / [phone]
180
Technical Information
Figure 18
Figure 20
[phone]
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Percent of Original Impedance vs.
Magnetic Field Strength. Measured on a
2643000301 using the HP4291A.
Percent of Original Impedance vs.
Magnetic Field Strength. Measured on a
2661000301 using the HP4291A.
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43 Material
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H(oersted)
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• FAX: (888) FERRITE / [phone] • www.fair-rite.com • E-Mail: [e-mail]
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Common-Mode Design
If the dc currents are so high that the resulting impedances are
not sufficient to suppress the conducted noise, the common-
mode approach might solve the problem. As shown in Figure 21,
in a common-mode design both current-carrying conductors will
pass through the same hole in the core. The dc fields will cancel
and the common-mode noise that is picked-up on both lines will
be attenuated. It should be pointed out that an EMI signal that is
on the line to the load and then returns from the load will not “see”
the core and will not be attenuated.
In applications with a large direct current in a single conductor,
the solution might be the use of an open magnetic circuit core
such as a wound ferrite rod. In automotive designs where the
ground is used as the return path, this often is the only option.
When high frequency operating signals, typically above 1 MHz,
are susceptible to EMI, the common-mode approach might be
used to solve that problem. In this instance common-mode is not
used for the current compensation, but rather for the compensa-
tion of the high frequency signals. These signal pairs will be not
be suppressed, yet any common-mode EMI will be attenuated.
The use of round or flat cable cores is a good example of this
application of this type of common-mode suppression.
P.O. Box J,One Commercial Row, Wallkill, NY 12589-0288
Note: (914) Area Code has changed to (845).
Figure 19
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Percent of Original Impedance vs.
Magnetic Field Strength. Measured on a
2644000301 using the HP4291A.
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44 Material
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H(oersted)
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100MHz
50MHz
25MHz
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14th Edition
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