TABLE OF CONTENTS
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EMI INTRODUCTION
EMI SUMMARY
BOARD LEVEL SHIELDS
Product Selection Guide
Introduction
Standard Design Shields
EZ Peel
™
Rigid Corner
ReCovr
™
ReMovl
Overview
FINGERSTOCK
Product Selection Guide
Introduction
Mounting Methods
Ordering Information
UltraSoft
®
Series
Recyclable Clean Copper
Slot Mount Series
Dual Slot Series
Teardrop Series
Compact PCI Symmetrical Mount
Alternate Slot Series
Variable Slot Mount
Symmetrical (S
3
) Slotted Shielding
Solid Top (S
3
) Symmetrical Slotted Shielding
Clip-On Symmetrical Shielding
No Snag Gasket
All-Purpose Series
Clip-On Series
)LTÐ-OLÄIBÐ%LLH,KÐ$>PHBQÐ
)LTÐ-OLÄIBÐ$>PHBQÐ
Large Enclosure Series
Double-Sided Contact Series
Foldover Series
Stainless Steel I/O Shielding
Flexible Low Compression Series
Clip-On Twist Series
Twist Series
Divider Edge Shielding
Card Guide Clip-On
Clip-On Perpendicular Shielding
Clip-On Perpendicular Grounding Strip
Clip-On Longitudinal Grounding Strip
Mini-Longitudinal Grounding Gasket
Longitudinal Grounding Series
Custom Stamping
Contact Strips / Contact Rings
&"""ÐÐ%LOFWLKQ>IÐ LKKB@QLOÐ$>PHBQÐ
DIN Connector Series
USB Connector
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40
Fiber Optic Shield 40
GBIC Fiber Optic Shield 40
"D" Connector Shielding / Slotted "D" 41
Precision Stamped Metals 42
Contacts 42
Custom Design 44
Metals Galvanic Compatibility Chart 46
VENT PANELS 48
MaxAir™ 49
Elecro-Air™ 50
Electrovent™ 51
FABRIC-OVER FOAM 52
Product Selection Guide 52
Introduction 54
EcoGreen™ 56
I/O / Gasket Selection Guide 57
-OLÄIBÐ0BIB@QFLKÐ$RFABÐ
I/O Selection Guide 62
Knitted Conductive Gaskets 65
Visual Part Reference Guide 66
Part Number Cross Reference 67
2IQO>ÅBU
®
68
All Mesh 69
Elastomer Core 70
Electroground
®
EMI Washers
72
Electromesh
®
Tape 75
Conductive Fabric 76
MRI "A" Fabric 77
Conductive Tape 78
ELECTRICALLY CONDUCTIVE ELASTOMERS 79
Introduction 79
Product Selection Guide 80
Case Study 81
Visual Part Reference Guide 85
Electroseal
™
Conductive Elastomer 86
Extrusions Guide 87
Gemini
™
Coextrusions 93
Fabricated Components Guide 95
Metal Impregnated Materials 99
Specialty Products 102
Automated Form-In-Place Gaskets 103
MICROWAVE ABSORBERS 105
Product Selection Guide 105
Design Guide 106
Q-Zorb
®
Ð%#
Q-Zorb
®
Ð%-
RFRET 4000 111
RFLS 5000 112
Analysis, Test and Prototype Development 113
3
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2
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EMI ESSENTIALS
Fabric-Over-Foam and Conductive Foam Wire Mesh Tape
Applications • Shielding or grounding of computer and
telecommunication equipment seams
and apertures
• Covers opened infrequently for servicing
(6-12 times per year)
• Long lasting resiliency is ideal for highly
sensitive components in permanent or
semi-permanent enclosures
• Consistent point-to-point contact for high
shielding effectiveness over the life of the
gasket
jÐ!BPFDKÐÅBUF?FIFQVÐMOLSFABPÐDOLRKAFKDÐ>KAÐ
shielding solutions for I/O shielding panels,
disk drive insulators, ground planes or circuit
boards, electromedical devices, keyboard
devices
• Mask-and-peel tape for painted electronic
enclosures
• Cable and wire harness wrapping
%D@STQDRÐ@MCÐ!DMDÎSR
-OLAR@QÐ%FDEIFDEQP
jÐ2)Ð3,Ð>KAÐ%ÐÅ>JBÐOBQ>OA>KQ
• Ideal for applications requiring low
pressure force
• Self-terminating cut-to lengths
jÐ%FDEÐ@LKAR@QFSFQVÐ>KAÐPEFBIAFKDÐ>QQBKR>QFLK
• Galvanically-compatible with most mating
surfaces
jÐ%FDEÐ>?O>PFLKÐ>KAÐPEB>OÐOBPFPQ>K@B
• Most economical gasket for low-cycling
applications
jÐ%FDEÐPEFBIAFKDÐBCCB@QFSBKBPPÐLSBOÐ?OL>AÐ
frequency range
jÐS>FI>?IBÐFKÐTFABÐS>OFBQVÐLCÐPFWBPÐ>KAÐPE>MBP
• Knit construction for long lasting resiliency
• Versatile mounting options
• Available with elastomer gasket for moisture
and dust sealing
• Simple installation
jÐ&AB>IIVÐPRFQBAÐCLOÐQEFKÐLOÐILTMOLÄIBÐ
applications
• Conductive foil tape with release mask for
painted enclosures
• Tin copper cloth and nickel copper cloth
versions provide easy-to-handle alternatives
to foils
Electrical Shielding
Effectiveness
1O>KPCBOÐ&JMBA>K@BÐÐ*%W
>85 dB 90 - 105 dB —
%ÄBIAÐÐ*%WÐ
*LAFÄBAÐ*FIÐ
30 - 45 dB 55 - 65 dB —
-I>KBÐ4>SBÐÐ$%WÐ
*LAFÄBAÐ*FIÐ
90 - 100 dB 80 - 115 dB 85 - 95 dB
Surface Resistivity <0.07 ohms/square N/A
Low surface resistivity based on material selection
Volume Resistivity N/A 0.0004 - 0.114 ohm-cm N/A
Mechanical
S>FI>?IBÐ0FWBÐ/>KDB
%BFDEQÐÐÐÐÐÐ %BFDEQÐÐÐÐÐÐÐ 4FAQEÐÐÐÐÐÐÐ
1EF@HKBPPÐÐÐÐÐÐÐ
!BÅB@QFLKÐ,MBO>QFKDÐ/>KDB ÐÐÐABÅB@QFLK ÐÐÐABÅB@QFLK N/A
Compression Force
(based on shape selection)
3 - 10 Ibs/in. ft. (4,5 - 15,0 Kg/m)
ÐÐABÅB@QFLKÐABMBKABKQÐLKÐCL>JÐ
selection and shape)
From 6 - 50 Ibs/in. ft.
(8,8 - 74 Kg/m) round
N/A
Compression Set ÐÐÐÐÐABÅB@QFLK 10% @ 20% compression N/A
Joint Unevenness
Accommodation
0.020 - 0.050 (0,51 - 1,27) 0.010 - 0.300 (0,25 - 7,6) N/A
Compound/Material
Availability
LSBOÐ#I>JBÐOBQ>OA>KQÐJBQ>IIFWBAÐ+F RÐ
Tin/Cu and silver woven or non-woven textile.
LOBÐ#I>JBÐOBQ>OA>KQÐROBQE>KBÐ1-"
BeCu, Monel, aluminum, tin-plated steel,
tin-plated brass, Enviroseal version with
neoprene or silicone
Tin-plated copper, copper foil, nickel copper
cloth tape
Temperature Range -40 - 158°F (-40 - 70°C) Enviroseal -103 - 500°F (-75 - 260°C) 50 - 500°F (10 - 260°C) based on material
selection
S>FI>?IBÐ-OLÄIBP Round, rectangular, square “D”, “C”, “J”, “P”,
“U”, clip-on, knife edge
Round, rectangular, square, single-round with
ÄKÐALR?IBOLRKAÐTFQEÐÄK
Rolls
Mounting Methods Groove, PSA, clip-on, dart Groove, pressure-sensitive adhesive,
mechanical fasteners, channel mount
Pressure-sensitive adhesive, conductive or
non-conductive
Custom Shapes Available Cut-to lengths, mitered and spliced corners,
HFPP@RQÐLQEBOÐMOLÄIBP
RQQLÐIBKDQEPÐJFQBOBAÐ@LOKBOPÐÅ>QÐQ>MBÐ>KAÐ
EMI washers
Die-cut shapes
Environmental
Fluid Seal
N/A "KSFOLPB>IÐMOLAR@QÐLKIVÐJLFPQROBÐO>FK N/A
Air/Dust Provides barrier against dust Enviroseal product only N/A
Galvanic Compatibility Compatible with a wide variety of mating
PROC>@BPlWFK@Ð>IRJFKRJÐPQ>FKIBPPÐPQBBIÐBQ@
Variety of platings to ensure galvanic
compatibility with mating surface
Wide variety of materials available to meet
galvanic compatibility requirements
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Overview of EMC/RFI Issues
The phenomenon of electromagnetic interference (EMI) is familiar to virtually everyone, even if they do not
RKABOPQ>KAÐQEBÐRKABOIVFKDÐMOFK@FMIBPÐ*LPQÐMBLMIBÐE>SBÐTFQKBPPBAÐÄOPQE>KAÐQEBÐBCCB@QPÐLCÐFKQBOCBOBK@BÐ
1LÐ@LKQOLIÐ"*&ÐDLSBOKJBKQÐLOD>KFW>QFLKPÐPR@EÐ>PÐQEBÐ# Ð 0Ð>KAÐ"" ÐJ>KA>QBÐQE>QÐJ>KRC>@QROBOPÐJ>VÐ
not design, produce or sell electronic equipment that jams the public broadcast services. In other instances,
however, EMI can constitute more than a mere nuisance. The military and medical communities, for example,
require trouble-free operation of their electronic equipment in adverse electromagnetic environments since
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that “the apparatus has an adequate level of intrinsic immunity to electromagnetic disturbance to enable it
to operate as intended”.
EMC Design of High Speed Systems
The interference and susceptibility (immunity) effects of electronic apparatus are created by time-variant
BIB@QOLJ>DKBQF@ÐÄBIAPÐTEF@EÐJ>VÐ?BÐMOLM>D>QBAÐ>ILKDÐ>Ð@LKAR@QFKDÐJBAFRJÐLOÐ?VÐO>AF>QFLKÐQEOLRDEÐPM>@BÐ
Because the source of the conducted and radiated interference energy levels may be related, a coordinated
systems design effort is required to reduce these effects.
A design program for an equipment item that must meet both an emission and an immunity requirement
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j 0RMMOBPPFLKÐ/BAR@FKDÐQEBÐFKQBOCBOBK@BÐ>QÐFQPÐPLRO@B
j &PLI>QFLKÐ&PLI>QFKDÐQEBÐLCCBKAFKDÐ@FO@RFQPÐ?VÐÄIQBOFKDÐDOLRKAFKDÐ>KAÐPEFBIAFKD
j !BPBKPFQFW>QFLKÐ&K@OB>PFKDÐQEBÐFJJRKFQVÐLCÐ>KVÐPRP@BMQF?IBÐ@FO@RFQP
These three steps should be carried on throughout the entire equipment design and implemented as early
as possible within the design program.
Effects of Logic Speed
1EBÐQOBKAÐFKÐQLA>VgPÐBIB@QOLKF@ÐABSF@BPÐFPÐC>PQBOÐPJ>IIBOÐ>KAÐAFDFQ>IÐO>QEBOÐQE>KÐ>K>ILDÐ*LPQÐBNRFMJBKQÐ
ÐLCÐQLA>VÐ@LKQ>FKPÐAFDFQ>IÐ@FO@RFQPÐ1LA>VgPÐAFDFQ>IÐABPFDKBOÐJRPQÐ@OB>QBÐ>Ð@FO@RFQÐ?L>OAÐQE>QÐE>PÐQEBÐ
lowest possible EMI, combined with the highest possible operating/processing speeds. Design of the PCB
FPÐQEBÐJLPQÐ@OFQF@>IÐ"* ÐFKÅRBK@FKDÐC>@QLOÐCLOÐ>KVÐPVPQBJÐPFK@BÐSFOQR>IIVÐ>IIÐ>@QFSBÐABSF@BPÐ>OBÐIL@>QBAÐLKÐ
the board. It is the changing current (accelerated electron movement) produced by the active devices that
result in EMI.
Design Approaches
1EBOBÐ>OBÐQTLÐ>MMOL>@EBPÐQE>QÐ@>KÐ?BÐRPBAÐQLÐOBAR@BÐQEBÐBJFPPFLKÐCOLJÐQEBÐ- Ð?L>OAÐ1EBÐÄOPQÐ>MMOL>@EÐFPÐ
to operate the circuit at the slowest speeds consistent with the functionality of the system, lay out the PCB
with the smallest possible loop areas (especially the high speed devices), and insert suppression components
PR@EÐ>PÐÄIQBOPÐCBOOFQBÐ?B>APÐ>KAÐ?VM>PPÐ@>M>@FQLOPÐFKQLÐQEBÐ@FO@RFQÐQLÐOBAR@BÐFQPÐ?>KATFAQEÐ1EBPBÐQB@EKFNRBPÐ
will result in a desired decrease in the high frequency harmonic amplitudes and circuit bandwidth and a
corresponding undesired decrease in both the operating speed and system reliability. The use of slower
PMBBAPÐTFQEÐOBAR@BAÐ?>KATFAQEÐTFIIÐEBIMÐQLÐABPBKPFQFWBÐQEBÐ@FO@RFQÐQLÐBUQBOK>IÐPRP@BMQF?FIFQVÐÄBIAP
The second is to use shielding. Shielding is the only non-invasive suppression technique. Since the shielding
is not inserted into the circuit, it does not affect the high frequency operating speed of the system, nor does
it affect the operation of the system should changes be made to the design in the future. In addition,
shielding does not create timing problems and waveform distortion; it does not decrease system reliability;
and it reduces crosstalk. Plus, shielding works for both emission suppression as well as susceptibility
(immunity) problems.
Even with the overall advantages of shielding, the most cost-effective approach is to use a combination
of circuit suppression/hardening and shielding.
EMI INTRODUCTION