1© KEMET Electronics Corporation • P.O. Box 5928 • Greenville, SC 29606 (864) 963-6300 • www.kemet.com E5002_ESD-R-B • 3/28/2017
One world. One KEMET
Overview
The KEMET ESD-R-B Series solid
toroidal cores with snail-shaped case
are designed for use on round cable.
The wide range of MnZn and NiZn
options allows for targeting of specic
frequency ranges.
Benets
• MnZn (≤ 100 MHz, AM band range)
and NiZn (≤ 300 MHz, FM band
range) options available
• Solid construction
• Case ame resistant rating:
UL94V–2
Applications
• Consumer electronics
EMI Core
ESD-R-B Series Toroidal Cores with Snail-shaped Case
3.0
A
øB
D
6.5
C
ø5.1
ESD-R-B Series
Shape and Dimensions
Toroidal Cores with
Snail-shaped Case
[RoHS Compliant]
Toroidal Cores with
Snail-shaped Case
[RoHS Compliant]
1 10 100 1000 1 10 100 1000
1 10 100 1000 1 10 100 1000
1
10000
1000
100
10
1T
2T
3T
1
10000
1000
100
10
1T
2T
3T
1
10000
1000
100
10
1T
2T
3T
1
10000
1000
100
10
1T
2T
3T
Impedance ()
Frequency (MHz)
ESD-R-19B
Impedance ()
Frequency (MHz)
ESD-R-19D-B
Impedance ()
Frequency (MHz)
ESD-R-25B
Impedance ()
Frequency (MHz)
ESD-R-25D-B
Impedance vs. Frequency
[mm]
ESD-R-19B 21.5 8.8 13.0 18.5 ● white ESD-R-19S
ESD-R-19D-B 21.5 8.8 13.0 18.5 ● black ESD-R-19SD
ESD-R-25B 29.3 13.9 15.0 23.0 ● white ESD-R-25S
ESD-R-25D-B 29.3 13.9 15.0 23.0 ● black ESD-R-25SD
ESD-R-38B 42.4 17.9 16.0 28.0 ● white ESD-R-38D
ESD-R-38D-B 42.4 17.9 16.0 28.0 ● black －
ESD-R-47B 51.5 25.5 17.5 34.0 ● white －
ESD-R-47D-B 51.5 25.5 17.5 34.0 ● black －
Model
Dimensions (mm)
Frequency range
Color of case
Compatible toroidal core
A B C D up to 100MHz up to 300MHz
(bare type)
(mainly AM band range) (mainly FM band range)
※Above frequency range is a reference only. Please test with actual device before use. ※Flame resistant grade of the case : UL94V-2
Turns and Impedance Characteristics
When the desired performance of an EMI core cannot
be obtained with a single pass through the core, the
impedance characteristics can be changed with multiple
turns.
A turn is counted by the number of lead-wire windings
which pass through the inner hole of the core. Windings
on the outside of the core do not count. See Figure 1 for
examples of one, two, and three turns.
Adding turns will result in higher impedance while also
lowering the effective frequency range. See Figure 2 for
an example.
Core Material and Effective Frequency Range
There are two ferrite material options for
KEMET EMI Cores: Nickel-Zinc (Ni-Zn) and
Manganese-Zinc (Mn-Zn). Each core material
has a different resistance and effective
frequency range. The Mn-Zn core material
has lower resistance compared to the Ni-
Zn; therefore, be sure to provide adequate
insulation before use.
For reference, the Ni-Zn core material is
typically effective for the frequencies in the
MHz band range such as the FM-band, while
the Mn-Zn core material is typically effective for
the kHz band range such as the AM-band. See
Figure 3.
It is recommended to verify actual
effectiveness in the target application with
measurements.
EMI Core
5
EMI Cores
Ring Type
There are two materials of ferrite, Ni-Zn series and Mn-Zn ser ies. Ni-Zn series is e
ive for kHz band range.
Note that above
e band range i s a reference only. Examination of s
with actual instrument is necessary.
As Mn-Zn series has lower resistance compared to Ni-Zn series, make sure to provide
adequate insulation before use.
Characteristics and how to count turns
Number of turns are counted by how many times the lead wire pa sses through the inner
hole of the core. Do not count the number of lead wire winding outside the core, as it results
When desired performance can not be obtained just b y 1 turn, impedance characteristics
value can be raised b y increasing th e turn. In this case, the
e frequency band should
be checked that it is in the desired range as adding turns resu lts in lowering down the
Tips on EMI Core Usages
（Represe ntative Example：ESD-R-16C）
Fig.1 How to count turns Fig.2 Relationship between impedance an d turn counts
*Number of lead wire wound outside the core + 1
= Number of read wire passes through the inner
hole of the core
= Turn count
Mn-Zn series vs Ni-Zn series ｜Z｜-f Characteristics (representative example)
(measurement condition: measured with same-dimension ring core)
Fig.3 te
AM band range FM band range
MnZn series core
NiZn series core
Impedance (Ω)
1000
100
10
1
0.01 0.1 1 10 100 1000
Impedance Increase
Resonance point changes to lower band
3T
2T
1T
Frequency (MHz)
Impedance (Ω)
Frequency (MHz)
10000
1 10 100 1000
1000
100
10
1
3T2T1T
Figure 1 – How to count turns
EMI Core
5
EMI Cores
Ring Type
There are two materials of ferrite, Ni-Zn series and Mn-Zn ser ies. Ni-Zn series is e
ive for kHz band range.
Note that above
e band range i s a reference only. Examination of s
with actual instrument is necessary.
As Mn-Zn series has lower resistance compared to Ni-Zn series, make sure to provide
adequate insulation before use.
Characteristics and how to count turns
Number of turns are counted by how many times the lead wire pa sses through the inner
hole of the core. Do not count the number of lead wire winding outside the core, as it results
When desired performance can not be obtained just b y 1 turn, impedance characteristics
value can be raised b y increasing th e turn. In this case, the
e frequency band should
be checked that it is in the desired range as adding turns resu lts in lowering down the
Tips on EMI Core Usages
（Represe ntative Example：ESD-R-16C）
Fig.1 How to count turns Fig.2 Relationship between impedance an d turn counts
*Number of lead wire wound outside the core + 1
= Number of read wire passes through the inner
hole of the core
= Turn count
Mn-Zn series vs Ni-Zn series ｜Z｜-f Characteristics (representative example)
(measurement condition: measured with same-dimension ring core)
Fig.3 te
AM band range FM band range
MnZn series core
NiZn series core
Impedance (Ω)
1000
100
10
1
0.01 0.1 1 10 100 1000
Impedance Increase
Resonance point changes to lower band
3T
2T
1T
Frequency (MHz)
Impedance (Ω)
Frequency (MHz)
10000
1 10 100 1000
1000
100
10
1
3T2T1T
Figure 2 – Relationship between impedance and turn count.
(Representative example: ESD-R-16C)
EMI Core
5
EMI Cores
Ring Type
There are two materials of ferrite, Ni-Zn series and Mn-Zn ser ies. Ni-Zn series is e
ive for kHz band range.
Note that above
e band range i s a reference only. Examination of s
with actual instrument is necessary.
As Mn-Zn series has lower resistance compared to Ni-Zn series, make sure to provide
adequate insulation before use.
Characteristics and how to count turns
Number of turns are counted by how many times the lead wire pa sses through the inner
hole of the core. Do not count the number of lead wire winding outside the core, as it results
When desired performance can not be obtained just b y 1 turn, impedance characteristics
value can be raised b y increasing th e turn. In this case, the
e frequency band should
be checked that it is in the desired range as adding turns resu lts in lowering down the
Tips on EMI Core Usages
（Represe ntative Example：ESD-R-16C）
Fig.1 How to count turns Fig.2 Relationship between impedance an d turn counts
*Number of lead wire wound outside the core + 1
= Number of read wire passes through the inner
hole of the core
= Turn count
Mn-Zn series vs Ni-Zn series ｜Z｜-f Characteristics (representative example)
(measurement condition: measured with same-dimension ring core)
Fig.3 te
AM band range FM band range
MnZn series core
NiZn series core
Impedance (Ω)
1000
100
10
1
0.01 0.1 1 10 100 1000
Impedance Increase
Resonance point changes to lower band
3T
2T
1T
Frequency (MHz)
Impedance (Ω)
Frequency (MHz)
10000
1 10 100 1000
1000
100
10
1
3T2T1T
Figure 3 – Effective band range of Mn-Zn and Ni-Zn ferrite core material.
(Representative example, measured with same-dimension ring core)
