2743037447 Fair-Rite, 2743037447 Datasheet - Page 174

• Manufacturer Part Number: 2743037447
• Description: CHIP BEAD,Ferrite
• Manufacturer: Fair-Rite

Specifications of 2743037447

• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

174
Fair-Rite Products Corp.
Phone: (888) FAIR RITE / [phone]
Technical Information
Introduction
The following pages will focus on Soft Ferrites used in the
application of electromagnetic interference (EMI) suppression.
Although the end use is an important issue and some applica-
tions are mentioned, this technical section is not intended to be
a design manual, but rather, an aid to the designer in under-
standing and choosing the optimum ferrite material and com-
ponent for their particular application. Ferrite suppressor cores
are simple to use, in either initial designs or retrofits, and are
comparatively economical in both price and space. Ferrite
suppressors have been successfully employed for attenuating
EMI in computers and related products, switching power sup-
plies, electronic automotive ignition systems, and garage doors
openers, to name just a few.
Use of Ferrite Suppressor Cores
The United States was one of the first countries to recognize the
potential problems caused by electromagnetic pollution. As a
result the FCC was charged with the responsibility of promul-
gating rules and regulations to control and enforce limits on
high frequency interference.
Figure 1 shows the current radiation limits as defined by FCC
Rules Part 15, for class A (industrial) and class B (mass-market)
equipment.
Contrary to the times when these regulations were first enforced
and designing for EMI protection was often an afterthought
rather than a forethought, a major portion of today’s circuitry is
incorporating EMI safeguards in its initial design. Many ap-
proaches can be used to comply with design or specification
limits for EMI. Attention to basic circuit design, component
layout, shielded enclosures and other use of shielding materi-
als may be considered. For reducing or eliminating conducted
EMI on printed circuit boards in wiring and cables, ferrite
components have been used very successfully for decades.
The ferrite core introduces into the circuit a frequency variable
impedance, see Figure 2. The core will not affect the lower
frequency operating signals but does block the conduction of
the EMI noise frequencies. The Figures 3 and 4 are photo-
graphs of a representative sampling of the Fair-Rite Products
Corp. product line of suppressor cores.
How to Choose Ferrite Components
for EMI Suppression
[phone]
• FAX: (888) FERRITE / [phone] • www.fair-rite.com • E-Mail: [e-mail]
[phone]
* Measured using a 50-ohm LISN
** Measured at a 3-meter distance
P.O. Box J,One Commercial Row, Wallkill, NY 12589-0288
216 MHz – 960 MHz
Figure 1 FCC Radiation Limits for class A & B equipment.
450 kHz – 1.6 MHz
88 MHz – 216 MHz
1.6 MHz – 30 MHz
30 MHz – 88 MHz
Figure 2
Note: (914) Area Code has changed to (845).
above 960 MHz
Frequency
250
200
150
100
50
0
10
6
Impedance, reactance, and resistance vs.
frequency for a ferrite core in 43 material.
Conducted Limits*
Radiated Limits**
10
Frequency (Hz)
7
50 dBuV/m
53 dBuV/m
56 dBuV/m
64 dBuV/m
Class A
60 dBuV
70 dBuV
Z
R
S
10
X
8
L
40 dBuV/m
43 dBuV/m
46 dBuV/m
54 dBuV/m
50 dBuV
60 dBuV
Class B
14th Edition
10
9