Datasheet

2© KEMET Electronics Corporation • KEMET Tower • One East Broward Boulevard E5003_ESD-R-H • 9/14/2018
Fort Lauderdale, FL 33301 USA • 954-766-2800 • www.kemet.com
EMI Core – ESD-R-H Toroidal Cores for Round Cables for Low & High Frequency & High Heat Resistance (with case)
Part Number System
ESD- R- 12 M-H
Series Shape Type
Core Size
Outer Dimension Code (mm)
Core Material
ESD- Ring See Table 1 H / M-H = Mn-Zn
N-H = Ni-Zn
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
MnZn core material has a lower resistance
compared to the Ni-Zn; therefore, adequate
insulation is required before use.
The Ni-Zn core material is typically effective
for 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 measure the actual
frequency range effectiveness in the target
application.
3T2T1T
Figure 1 – How to count turns
Impedance Increase
Resonance point changes to lower band
3T
2T
1T
Impedance (Ω)
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)
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 3 – Effective band range of Mn-Zn and Ni-Zn ferrite core material.
(Representative example, measured with same-dimension ring core)