Datasheet

Chip Ferrite BeadChip EMIFILr
Chip Common Mode Choke Coil
Block Type EMIFILrMicrowave Absorber
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C31E.pdf
09.4.20
122
NFW31S's steep attenuation
characteristic means excellent EMI
suppression without waveform
cornering.
3-terminal capacitors suppress
signal frequencies as EMI
frequencies so the signal waveform
is distorted.
Combinations of inductors and
capacitors can yield a steep
attenuation characteristic, but they
require a great deal more mounting
space.
Moreover, at high frequencies the
EMI suppression is less than that
obtained by NFW31S.
Signal Waveform 20ns/div
1V/div
()
Noise Spectrum
(10:1 Active Probe)
100
80
60
40
20
0
100 200 300
400 500
Frequency
(
MHz
)
Noise Level (dBµV)
100
80
60
40
20
0
100 200 300
400 500
Frequency (MHz)
Noise Level (dBµV)
Level before
filter mounting
100
80
60
40
20
0
100 200 300
400 500
Frequency (MHz)
Noise Level (dBµV)
Level before
filter mounting
100
80
60
40
20
0
100 200 300
400 500
Frequency (MHz)
Noise Level (dBµV)
Level before
filter mounting
10MHz
74ALS04 74ALS00
EMI
Suppression Filter
Measuring
Point
Example of EMI Suppression
in an Actual Circuit
Type of Filter / EMI Suppression Effect / DescriptionSignal Wave Form
Signal Waveform
and Noise Spectrum
before Filter Mounting
NFW31S Series
(Cut-off frequency 50MHz)
Conventional Chip
Solid Type EMI Filter
(NFM41CC 470pF)
Filter Combined
with Conventional LCs
Measuring Circuit
20ns/div
1V/div
L: Chip Inductor
C: Chip Capacitor
(270pF)
L
C
L
NFW31 Series
EMI
Suppression
Effect
)(