15th Edition
1
Table of Contents
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icon above or click below for product category.
Our Position on Quality and the Environment.............................................................................................................................I.F.C.
Introduction ......................................................................................................................................................................................2
Magnetic Properties of Fair-Rite Materials .......................................................................................................................................4
Fair-Rite Materials ............................................................................................................................................................................7
Board Components
Solder Profile....................................................................................................................................................................28
EMI Suppression Beads...................................................................................................................................................29
Beads on Leads ...............................................................................................................................................................34
PC Beads (Through Hole) ...............................................................................................................................................36
PC Beads (Surface Mount)...............................................................................................................................................38
Wound Beads...................................................................................................................................................................42
Multi-Aperture Cores........................................................................................................................................................44
SM Beads (Differential Mode) ..........................................................................................................................................47
SM Beads (Common-Mode) ............................................................................................................................................51
Chip Beads.......................................................................................................................................................................54
Chip Arrays........................................................................................................................................................................58
Chip Inductors...................................................................................................................................................................60
Engineering Kits........................................................................................................................................................68
Cable Components
Round Cable EMI Suppression Cores .............................................................................................................................70
Round Cable Snap-Its......................................................................................................................................................75
Split Round Cable EMI Suppressor Cores.......................................................................................................................79
Flat Cable EMI Suppression Cores..................................................................................................................................83
Flat Cable Cores Assembly Clips.................................................................................................................................... .86
Flat Cable Snap-Its .........................................................................................................................................................88
Connector EMI Suppression Plates ................................................................................................................................89
Miscellaneous Suppression Cores...................................................................................................................................91
Absorber Tiles...................................................................................................................................................................92
Inductive Components
Open Magnetic Circuit
Rods ..................................................................................................................................................................96
Rod Information.................................................................................................................................................
98
Antenna/RFID Rods ........................................................................................................................................100
Tack Bobbin Cores ..........................................................................................................................................103
Bobbins ...........................................................................................................................................................104
Closed Magnetic Circuit
Toroids .............................................................................................................................................................106
Pot Cores.........................................................................................................................................................114
E Cores ...........................................................................................................................................................118
I Cores................................................................................................................................................ .............122
ETD Cores ......................................................................................................................................................124
U Cores ...........................................................................................................................................................126
PQ Cores.........................................................................................................................................................128
EP Cores .........................................................................................................................................................130
References
Reference Tables............................................................................................................................................................132
Glossary of Terms ..........................................................................................................................................................133
Soft Ferrite References ..................................................................................................................................................134
Magnetic Design Formulas ............................................................................................................................................136
Wire Table of Copper Magnet Wire.................................................................................................................................137
Technical Articles
The Effect of Direct Current on the Inductance of a Ferrite Core ...................................................................................138
Use of Ferrites in Broadband Transformers ...................................................................................................................143
How to Choose Ferrite Components for EMI Suppression ............................................................................................147
Ferrite Tile Absorbers for EMC Test Chamber Applications .......................................................................................... 157
Numerical Index
........................................................................................................................................................................159
Copyright
©
2005 by Fair-Rite Products Corp.
All rights reserved. No part of the contents of this book may be published or transmitted in any form or by any means with-
out the expressed written permission of the publisher.
F air-Rite Produ ct s C or p.
Phone:
(888) FAIR RITE / (845) 895-2055 •
FAX: (888) FERRITE / (845) 895-2629
(888) 324-7748
(888) 337 -7483
PO Box J, One Commercial Row, Wallkill, NY 12589-0288
•
www.fair-rite.com
•
E-Mail: ferrites@fair-rite.com
2
15th Edition
Introduction
History
The history of magnetism began with the discovery of the properties
of a mineral called magnetite (Fe
3
O
4
). The most plentiful deposits
were found in the district of Magnesia in Asia Minor (hence the
mineral’s name) where it was observed, centuries before the birth
of Christ, that these naturally occurring stones would attract iron.
Later on it found application in the lodestone of early navigators.
In 1600 William Gilbert published
De Magnete,
the first scientific
study on magnetism. In 1819 Hans Christian Oersted observed that
an electric current in a wire affected a magnetic compass needle,
thus with later contributions by Faraday, Maxwell, Hertz and others,
the new science of electromagnetism came into being.
Even though the existence of naturally occurring magnetite, a weak
type of hard ferrite, had been known since antiquity, producing an
analogous soft magnetic material in the laboratory proved elusive.
Research on magnetic oxides was going on concurrently during
the 1930’s, primarily in Japan and the Netherlands. However, it
was not until 1945 that J. L. Snoek of the Philips’ Research Labor-
atories in the Netherlands succeeded in producing a soft ferrite
*
material for commercial applications.
Fair-Rite Products Corp. was not far behind in the manufacture
and sale of soft ferrites for use in the electronics industry. It was
formed in 1952 and officially started operations in 1953. The ensu-
ing years have seen a rather crude product, which was available
in only a few shapes and materials, develop into a major line of
ferrite components for inductive devices, produced in many core
configurations with a wide selection of materials. The application
of ferrites in EMI suppression as shield beads and broadband
chokes, where an effective resistive impedance is produced at
high frequencies, has grown so fast in the last decade, that their
use as EMI suppressors is limited only by the imagination of the
end user.
of iron oxide. Fair-Rite manufactures four broad groups of soft
ferrite materials:
Manganese zinc (Fair-Rite 31, 33, 73, 75, 76, 77, 78 and 79 mate-
rial)
Nickel zinc (Fair-Rite 42, 43, 44, 51, 52, 61, 67 and 68 material)
Manganese (Fair-Rite 85 material)
Magnesium zinc (Fair-Rite 46 material)
Manganese zinc ferrites are completely vitrified and have very low
porosity. They have the highest permeabilities and exhibit volume
resistivities ranging from one hundred to several thousand ohm-
centimeter. Manganese zinc ferrite components are used in tuned
circuits and magnetic power designs from the low kilohertz range
into the broadcast spectrum. These ferrites have a linear expan-
sion coefficient of approximately 10 ppm/
o
C.
The nickel zinc ferrites vary in porosity, and frequently contain ox-
ides of other metals, such as those of magnesium, manganese,
copper or cobalt. Volume resistivities range from several kilohm-
centimeter to tens of megohm-centimeter. In general, they are used
at higher frequencies (above 1 MHz), and are suitable for low flux
density applications. Nickel zinc ferrites have a linear expansion
coefficient of approximately 8 ppm/
o
C.
The manganese ferrite is a dense, temperature stable material
displaying a high degree of squareness in its hysteresis loop.
This makes this material uniquely suited for such applications as
multiple output control in switched-mode power supplies and high
frequency magnetic amplifiers.
The magnesium zinc ferrite has similar characteristics as NiZn
ferrite. The composition of MgZn material does not contain any
nickel, hence avoiding potential environmental issues as well as
reducing the raw material component cost.
As is evident from the flow diagram on page 3, there is consid-
erable processing involved, and the manufacturing cycle will take
a minimum of two weeks. The parts listed in the catalog repre-
sent a broad cross section of the wide variety of cores produced
by Fair-Rite Products. Large OEM quantitites are manufactured
by Fair-Rite to order. Most of the more commonly used parts
are stocked by our distributors, offering prompt deliveries. For a
complete listing of our distributors visit our site on the Internet at
www.fair-rite.com.
Many of the parts produced by Fair-Rite are made to customer
specifications, and we welcome inquiries involving application-
specific designs. We have the capability to design tooling rapidly,
and have it fabricated either by our own tool shop or by outside
vendors.
Soft Ferrites
The single most important characteristic of soft ferrites, as com-
pared to other magnetic materials, is the high volume resistivity
exhibited in the monolithic form. Since eddy current losses are
inversely proportional to resistivity and these losses increase with
the square of the frequency, high resistivity becomes an essential
factor in magnetic materials intended for high frequency operation.
The magnetic properties of ferrite components are isotropic, and
by employing various pressing, injection molding, and/or grind-
ing techniques, a wide range of complex shapes can be formed.
There is no other class of magnetic material that can match soft
ferrites in performance, cost and volumetric efficiency, from audio
frequencies into the GHz range.
During the last 50 years the basic constituents of ferrites have
changed little, but purity of raw materials and process control
have improved dramatically. Ferrites are ceramic materials with
the general chemical formula MO.Fe
2
O
3
, where MO is one or
more divalent metal oxides blended with 48 to 60 mole percent
*Footnote:
The difference between hard and soft ferrite is not tactile, but rather a magnetic characteristic.
Soft ferrite does not retain significant magnetization, whereas hard ferrite magnetization is considered permanent.
Fa ir- Rite Prod uct s C orp.
Phone:
(888) FAIR RITE / (845) 895-2055 •
FAX: (888) FERRITE / (845) 895-2629
(888) 324-7748
(888) 337 -7483
PO Box J, One Commercial Row, Wallkill, NY 12589-0288
•
www.fair-rite.com
•
E-Mail: ferrites@fair-rite.com
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