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© KEMET Electronics Corporation • KEMET Tower • One East Broward Boulevard

E5002_ESD-R-B • 9/14/2018

Fort Lauderdale, FL 33301 USA • 954-766-2800 • www.kemet.com

EMI Core – ESD-R-B Toroidal Cores for Round Cables for Low & High Frequency (with snail-shaped case)

Part Number System

ESD-

R-

19

B

Series

Shape Type

CoreSize

OuterDimensionCode(mm)

Core Material

ESD-

Ring

SeeTable1

B = Mn-Zn

D-B=Ni-Zn

Turns and Impedance Characteristics

WhenthedesiredperformanceofanEMIcorecannotbe

obtainedwithasinglepassthroughthecore,theimpedance

characteristicscanbechangedwithmultipleturns.

Aturniscountedbythenumberoflead-wirewindingswhichpass

throughtheinnerholeofthecore.Windingsontheoutsideofthe

core do not count.

SeeFigure1forexamplesofone,two,andthreeturns.

Addingturnswillresultinhigherimpedancewhilealsolowering

theeffectivefrequencyrange.

SeeFigure2foranexample.

Core Material and Effective Frequency Range

TherearetwoferritematerialoptionsforKEMET

EMICores:NickelZinc(Ni-Zn)andManganese

Zinc(Mn-Zn).Eachcorematerialhasadifferent

resistanceandeffectivefrequencyrange.The

MnZn core material has a lower resistance

comparedtotheNi-Zn;therefore,adequate

insulationisrequiredbeforeuse.

TheNi-Zncorematerialistypicallyeffective

forfrequenciesintheMHzbandrangesuchas

theFM-band,whiletheMn-Zncorematerialis

typicallyeffectiveforthekHzbandrangesuchas

theAM-band.SeeFigure3.

It is recommended to measure the actual

frequencyrangeeffectivenessinthetarget

application.

3T

2T

1T

Figure 1 – How to count turns

Resonance point changes to lower band

3T

2T

1T

Frequency (MHz)

10,000

1

10

100

1,000

1,000

100

10

1

Figure 2 – Relationship between impedance and turn count.

(Representative example: ESD-R-16C)

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 3 – Effective band range of Mn-Zn and Ni-Zn ferrite core material.

(Representative example, measured with same-dimension ring core)