1© KEMET Electronics Corporation • KEMET Tower • One East Broward Boulevard E5009_B-20 • 9/18/2018
Fort Lauderdale, FL 33301 USA • 954-766-2800 • www.kemet.com
One world. One KEMET
EMI Cores
B-20 Bead Cores for Round Cables for
Low & High Frequency (Bare & coated)
Benets
• MnZn≤10MHz(AMbandrange)andNiZn≤300MHz
(FMbandrange)optionsavailable
• Solid construction
• Bareandcoatedtypesavailable
Overview
TheKEMETB-20seriesbeadcoresaredesignedtouseon
roundcables.ThewiderangeofManganeseZinc(MnZn)
andNickelZinc(NiZn)optionsallowsfortargetingspecic
frequencyranges.
EMIcoresarepartofafamilyofpassivecomponents,
whichaddresstheissuesofnoiseorelectromagnetic
interference(EMI)incircuitsorsystems.
Applications
• Computers
• Telecommunications
• Industrialequipment
• Adapters
• Consumer electronics
Part Number System
B-20 L- 48 B-A
Series Core Material CoreSize
OuterDimension(mm) Type
B-20 F = Mn-Zn
L=Ni-Zn
xx = x.x mm Blank = Bare
B/B-A=Coated(except48B)
B-L=Insulationresistancetesting
2© KEMET Electronics Corporation • KEMET Tower • One East Broward Boulevard E5009_B-20 • 9/18/2018
Fort Lauderdale, FL 33301 USA • 954-766-2800 • www.kemet.com
EMI Core – B-20 Bead Cores for Round Cables for Low & High Frequency (Bare & coated)
Core Material and Effective Frequency Range
TherearetwoferritematerialoptionsforKEMET
EMICores:Nickel-Zinc(NiZn)andManganese
Zinc(MnZn).Eachcorematerialhasadifferent
resistanceandeffectivefrequencyrange.The
MnZn core material has a lower resistance
comparedtotheNiZn;therefore,adequate
insulationisrequiredbeforeuse.
TheNiZncorematerialistypicallyeffectivefor
frequenciesintheMHzbandrangesuchasthe
FM-band,whiletheMnZncorematerialistypically
effectiveforthekHzbandrangesuchastheAM-
band.SeeFigure1.
It is recommended to measure the actual
frequencyrangeeffectivenessinthetarget
application.
Environmental Compliance
AllKEMETEMIcoresareRoHScompliant.
Dimensions – Millimeters
OD
ID
T
See Table 1 for dimensions
Impedance (Ω)
Frequency (MHz)
AM band range FM band range
Mn-Zn series core
Ni-Zn series core
1,000
100
10
1
0.01 0.1 1 10 100 1,000
Figure 1 – Effective band range of Mn-Zn and Ni-Zn ferrite core material.
(Representative example, measured with same-dimension ring core)
3© KEMET Electronics Corporation • KEMET Tower • One East Broward Boulevard E5009_B-20 • 9/18/2018
Fort Lauderdale, FL 33301 USA • 954-766-2800 • www.kemet.com
EMI Core – B-20 Bead Cores for Round Cables for Low & High Frequency (Bare & coated)
Magnetic Permeability of Ferrite Material
Inordertoachievemostecientnoisereduction,itisimportanttoselectthematerialaccordingtothetargetfrequency
band.Dependingonitsmagneticpermeability,aparticularferritematerialwillbeeffectiveinacertainfrequencyband.
Aschematicrepresentationoftherelationshipbetweenthemagneticpermeabilityofeachmaterialandthecorresponding
effectivebandrangeisshowninFigure1.Materialswithhighermagneticpermeabilityareeffectiveinthelowerfrequency
range,whilethosewithlowermagneticpermeabilityareeffectiveinthehigherfrequencyrange.Thus,Mn-Znproductsare
mainlyusedforreducingconductionnoise,whileNi-Znproductsarecommonlyusedforradiationnoisecountermeasures.
Theeffectivefrequencyrangevariesdependingoncoreshape,sizeandnumberofwindings.Thisfrequencydependence
ofthemagneticpermeabilityasshowninthegureservesforreferencepurposesonlyanditshouldbetestedontheactual
devicetodetermineitseffectiveness.
S18H,S15H,10H,7H,5H,1400Land700LareKEMET’sproprietaryferritematerialnames.
Othermaterialscanalsobeavailableonrequest.
Figure 2 - Relationship between the magnetic permeability of each material and its effective frequency range
10 kHz
0
10,000
20,000
100 kHz 1 MHz 10 MHz 100 MHz 1 GHz
Effective Frequency Range
Magnetic Permeability
Ni-Zn Series
1400L
700L
S18H
S15H
10H
7H
5H
Mn-Zn Series
Lower magnetic permeability:
Higher noise suppression effect
in the higher frequency range
Higher magnetic permeability:
Higher noise suppression effect
in the lower frequency range
4© KEMET Electronics Corporation • KEMET Tower • One East Broward Boulevard E5009_B-20 • 9/18/2018
Fort Lauderdale, FL 33301 USA • 954-766-2800 • www.kemet.com
EMI Core – B-20 Bead Cores for Round Cables for Low & High Frequency (Bare & coated)
Performance Characteristics
Item Performance Characteristics
Operatingtemperature −25°Cto+85°C
Frequencyrange Lowfrequencyandhighfrequency
Outer diameter 2.5 – 9.7 mm
Inner diameter 0.8 – 4.8 mm
Thickness 1.2 – 8.0 mm
Type Bare and coated
Table 1 – Ratings & Part Number Reference
Part Number
Dimensions (mm) Weight
Type
Frequency Range1
OD ID T(g)
≤ 10 MHz
(AM band
range)
≤ 300 MHz
(FM band range)
B-20F-28
2.8 ±0.3
1.3 ±0.3
3.0 ±0.3
0.07
Bare
X
B-20F-38
3.8 ±0.3
1.5 ±0.3
4.3 ±0.3
0.21
Bare
X
B-20F-46
4.6 ±0.3
1.5 ±0.3
4.3 ±0.3
0.30
Bare
X
B-20F-57
5.7 ±0.3
1.5 ±0.3
8.0 ±0.3
0.91
Bare
X
B-20L-25
2.5 ±0.3
1.0 ±0.3
1.2 ±0.3
0.03
Bare
X
B-20L-34
3.4 ±0.3
0.8 ±0.3
4.4 ±0.3
0.19
Bare
X
B-20L-4 4
4.4 ±0.3
1.6 ±0.3
7.0 ±0.3
0.46
Bare
X
B-20L-48B
4.8 ±0.3
2.4 ±0.3
4.8 ±0.3
0.34
Bare
X
B-20L-48B-L
4.8 ±0.3
2.4 ±0.3
4.8 ±0.3
0.34
Bare
X
B-20L-48B-A
4.8 ±0.3
2.4 ±0.3
4.8 ±0.3
0.34
Coated
X
B-20L-95B
9.7 ±0.3
4.8 ±0.3
4.2 ±0.3
1.09
Coated
X
1 Frequency range is for reference only. Please test with actual device before use.
Impedance vs. Frequency
5© KEMET Electronics Corporation • KEMET Tower • One East Broward Boulevard E5009_B-20 • 9/18/2018
Fort Lauderdale, FL 33301 USA • 954-766-2800 • www.kemet.com
EMI Core – B-20 Bead Cores for Round Cables for Low & High Frequency (Bare & coated)
Impedance vs. Frequency cont.
6© KEMET Electronics Corporation • KEMET Tower • One East Broward Boulevard E5009_B-20 • 9/18/2018
Fort Lauderdale, FL 33301 USA • 954-766-2800 • www.kemet.com
EMI Core – B-20 Bead Cores for Round Cables for Low & High Frequency (Bare & coated)
Impedance vs. Frequency cont.
Packaging
Part Number Packaging Type Pieces per Box
B-20F-28
Bulk
60,000
B-20F-38 30,000
B-20F-46
B-20F-57 15,000
B-20L-25
30,000
B-20L-34
B-20L-44
B-20L-48B
B-20L-48B-L
B-20L-48B-A
B-20L-95B 15,000
7© KEMET Electronics Corporation • KEMET Tower • One East Broward Boulevard E5009_B-20 • 9/18/2018
Fort Lauderdale, FL 33301 USA • 954-766-2800 • www.kemet.com
EMI Core – B-20 Bead Cores for Round Cables for Low & High Frequency (Bare & coated)
Handling Precautions
EMICoresshouldbestoredinnormalworkingenvironments.WhiletheEMICoresthemselvesarequiterobustinother
environments,avoidexposuretohightemperatures,highhumidity,corrosiveatmospheresandlongtermstorageforcase,
snap-on and split types.
KEMETrecommendsthatmaximumstoragetemperaturenotexceed40°Candmaximumstoragehumiditynotexceed75%
relativehumidity.Atmospheresshouldbefreeofchlorine,sulfurandalkalibearingcompounds.Avoidalsostoragenear
strongmagneticeldsasthismightmagnetizetheproduct.
Temperatureuctuationsshouldbeminimizedtoavoidcondensationorcracksontheparts.Mechanicalshockscanbring
to cracks as well.
Export Control
For customers in Japan
Forproductsthatarecontrolleditemssubjecttothe“ForeignExchangeandForeignTradeLaw”ofJapan,theexportlicense
speciedbythelawisrequiredforexport.
For customers outside Japan
EMICoreproductsshouldnotbeusedorsoldforuseinthedevelopment,production,stockpilingorutilizationofany
conventionalweaponsormass-destructiveweapons(nuclearweapons,chemicalorbiologicalweapons,ormissiles),orany
other weapons.
8© KEMET Electronics Corporation • KEMET Tower • One East Broward Boulevard E5009_B-20 • 9/18/2018
Fort Lauderdale, FL 33301 USA • 954-766-2800 • www.kemet.com
EMI Core – B-20 Bead Cores for Round Cables for Low & High Frequency (Bare & coated)
KEMET Electronics Corporation Sales Offi ces
Foracompletelistofourglobalsalesoces,pleasevisitwww.kemet.com/sales.
Disclaimer
Allproductspecications,statements,informationanddata(collectively,the“Information”)inthisdatasheetaresubjecttochange.Thecustomerisresponsiblefor
checkingandverifyingtheextenttowhichtheInformationcontainedinthispublicationisapplicabletoanorderatthetimetheorderisplaced.AllInformationgiven
hereinisbelievedtobeaccurateandreliable,butitispresentedwithoutguarantee,warranty,orresponsibilityofanykind,expressedorimplied.
StatementsofsuitabilityforcertainapplicationsarebasedonKEMETElectronicsCorporation’s(“KEMET”)knowledgeoftypicaloperatingconditionsforsuch
applications,butarenotintendedtoconstitute–andKEMETspecicallydisclaims–anywarrantyconcerningsuitabilityforaspeciccustomerapplicationoruse.
TheInformationisintendedforuseonlybycustomerswhohavetherequisiteexperienceandcapabilitytodeterminethecorrectproductsfortheirapplication.Any
technicaladviceinferredfromthisInformationorotherwiseprovidedbyKEMETwithreferencetotheuseofKEMET’sproductsisgivengratis,andKEMETassumes
noobligationorliabilityfortheadvicegivenorresultsobtained.
AlthoughKEMETdesignsandmanufacturesitsproductstothemoststringentqualityandsafetystandards,giventhecurrentstateoftheart,isolatedcomponent
failuresmaystilloccur.Accordingly,customerapplicationswhichrequireahighdegreeofreliabilityorsafetyshouldemploysuitabledesignsorothersafeguards
(suchasinstallationofprotectivecircuitryorredundancies)inordertoensurethatthefailureofanelectricalcomponentdoesnotresultinariskofpersonalinjury
orpropertydamage.
Althoughallproduct–relatedwarnings,cautionsandnotesmustbeobserved,thecustomershouldnotassumethatallsafetymeasuresareindictedorthatother
measuresmaynotberequired.
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