EMI????????

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EMI????????

• Winson Ma (???)
• wma_at_lairdtech.com
• www.lairdtech.com
• 0755-27072412
• 13530161649
• Laird Technologies (SZ)

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??????1???( Fabric Over Foam FOF)
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Fibric foam PSA or Clip
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??????2????(Conductive Foam CF)
??????(CF)?????,???,????????I/O????
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??????3???? (Finger Stock)
???????????????,???????????????????,?????,????????
?????
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??????4???? Conductive Elastomers
Best for miniature devices.

• High shielding effectiveness
• Provides environmental sealing

• Extruded, molded, and die-cut
• Variety of compounds and fillers

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??????4???? Conductive Elastomers
Flat strip 5-10
Solid O 20-25
Solid D 5-20
Hollow O 0-50
Hollow D 20-50
Hollow P 25-50
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??????5 ?? Form-In-Place Elastomer

• Applied to die-cast metal or metalized plastic
  parts.

• Can be applied to non-planar surfaces.

• Can be applied with standard application machinery

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??????6 Board Level Shielding
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?????? -?? ???????????,????????????????????
?

• FOF???
• CF ???
• BLS???
• Finger Stock???????
• ?????????????????????Monel,BeCu??????????????????
  ??,??????????????????????????
• Elastomer ???????????????????????????????????????
  ?????????,????????
• Waveguide ?????????????????,???????????????????,?
  ??????????????????????????
• Tape ????????????????????,??????????,???????????,
  ???????,??????200????
• FIP ?????????????????????,????????????,??????????
  ????,??????????

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??EMI????? 1 -- ????????

• EMI?????????????,??????????????????,?????????.????
  ???????.??,??????????
• ???????????????????,???????????,???????????,??30-5
  0. ????????????,?????????????
• ????????????????????.??????????.
• ????(compress set)?????.
• ?????????????????????

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?????????????? ?????????????? ??????????????
? ? ??(?/??) ???()
??? FOF 4.83 good 30
?????? (Be Cu) 20.00 good 30
??? 50.00 30
???????(????) 42.00 30
???????(???) 49.50 30
D???? 7.50 good 30
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??EMI????? 2 -- R ? - C-Force
?????
?????
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??EMI????? 3 -- ?????? ???????????????,???????
??????????????????,????????,????(anode)???????

EMF 1.10 Volts
Connection
Anode ( )
Cathode ( - )
Zinc
Silver
Corrosion
Electrolyte
5
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?????????????????,??????????,??????
????????????????,??????????????????????,?????????
?????????????,???????????0.3V.
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??EMI????? 4 -????????
????
?90??
?????
???????
?????/??
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EMI??????????????
H ??????
W ??????
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??EMI????? 5 -????,?????
.120
.200

• ????,????,?????(???)
• ??????0.0048/???0.120
• 0.0048/0. 120
• 4.

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??EMI????? 6 -SE
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??Qualitative Shielding EffectivenessFive
Popular Gasket Types
120 --- 100 --- 80 --- 60 --- 40 ---
20 --- 0 ---
BeCu
BeCu Metal Gaskets
BeCu Mesh Gaskets
Monel Mesh Gaskets
Fabric Over Foam Gaskets
dB
Elastomer Gaskets

10k
100k 1M 10M 100M 1G
10G Frequency (Hz)
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??EMI????? 7 - EMI???????
??
??
??
??
???/???
?,?,?
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-???? ??
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??EMI????? 8 UL Rate

• Laird Technologies FOF UL ratings driven by foam
  and adhesive layer
• HB
• 80/20 Blend of TPE/DSM Foam w/ Polyethylene
  Adhesive
• FR Urethane Foam w/ Polyester Adhesive
• V0
• 100 DSM TPE Foam w/ Polyethylene Adhesive
• FR Urethane Foam w/ FR Polyester Adhesive

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??Five Popular Gasket Types
Parameter dB Falloff, 10k-10G
Variability Compression Range Closure
Pressure Usable in Shear Compression
Set Flame Retardant Fluid
Seal Surface Area
Weight Gas Permeable
BeCu Finger No 0 - 6 dB 20 - 80,45 20 /Lin
Ft 0,3 kg/cm Yes None Yes No Minimum Light No
BeCu Mesh Yes (Hi Freq) 6 - 18 dB 15 - 75,45 10
/Lin Ft 0,15 kg/cm No None Yes No Medium Light No
Monel Mesh Yes (Hi Freq) 6 - 18 dB 5 - 15,10 20
/sq in 1.41 kg/sq cm No Medium Yes No Maximum Med
ium No
Fabric o Foam Yes (VHiFreq) 0 - 10 dB 20 -
60,45 10 /Lin Ft 0,15 kg/cm Limited Low Yes No M
edium Light Yes
Ag Filled Elast Yes (LowFreq) gt40 - 60 dB 5 -
20,12 50 - 100 /sq in 3,5 - 7 kg/sq
cm No Highest Yes Excellent Medium Heaviest Yes
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??EMI????????????17??

1. Area of Interference Location of interference
2. Shielding Required How many dB at what range
   (90dB at 2GHz)
3. Conductivity , R include Material R Contact R
4. Usage Environment Outdoor /Indoor/ Dusty/
   Waterproof
5. Contact surface Material or finishing.
   Chromium, Tin or Zinc plated
6. Compression (Recommended compression 30)
7. Force required impact for deformation
8. Fire Rating UL94V0, UL94HB, UL94HF-1, No
   rating
9. Resistance to Abuse times?
10. Corrosion Resistance -Galvanic -Oxidation
11. Spring / Compression Set soft ?
12. Profile/Shape Selection standard or custom
    design ?
13. Operating Temperature 10 , 60 Deg C
14. Mounting Method Stick on, Clip on, Rivet on,
    Slot in, etc
15. Dimension of gap and space Height, Width,
    Length of gap or I/O
16. Criteria to follow Mil Spec, FCC, CE
17. Cost per Performance not cost consideration
    only