EMI Filters
KNF21 Series
Features
• Distributed constant type LC filter.
Prevents ringing caused by circuit
impedance.
• Stable noise attenuation over wide
frequency range.
• Low profile (T=0.95mm max.) suitable for
miniature electronic equipments.
• First class auto-placement
How to Order
KNF 21 100 C65 DA 3T S
①
② ③
④
⑤ ⑥ ⑦
①
Series
②
Size Code
21
025
050
100
C17
C33
C65
DA
2012 (EIA: 0805)
25MHz
50MHz
100MHz
17pF
33pF
65pF
200
400
200MHz
400MHz
③
Cut off Frequency
Applications
RoHS Compliant
• PCs, Laser Printers, Cellular Phone,
Clock Data Lines for LCD Display
• High Speed Video Signal Circuits and
Interface Circuits
• High Speed Digital Circuits
Attenuation
(Typical)
Rated Rated
Current Voltage
④
Capacitance
C130
C235
130pF
235pF
Specifications
Part Number
KNF21025C235DA3TS
KNF21050C130DA3TS
KNF21100C65DA3TS
KNF21200C33DA3TS
KNF21400C17DA3TS
Cut off Capacitance
Frequency (+50/
−20%)
25MHz
50MHz
100MHz
200MHz
400MHz
235pF
130pF
65pF
33pF
17pF
⑤
Application
Digital Circuit in General
T&R: 3000 pcs. (Std.)
Std.
200 to 600MHz (@20dB) 150mA 25VDC
350 to 850MHz (@20dB) 150mA 25VDC
450 to 950MHz (@20dB) 150mA 25VDC
700 to 1200MHz (@20dB) 150mA 25VDC
900 to 1400MHz (@20dB) 150mA 25VDC
⑥
Packaging
3T
⑦ Termination
S
Dimensions
L
(Unit: mm)
Attenuation Characteristics
KNF21 Series
R
W
10
0
Attenuation (dB)
IN
OUT
Input Direction Mark
−
10
−
20
−
30
−
40
−
50
KNF21025C235DA
KNF21050C130DA
KNF21100C65DA
KNF21200C33DA
KNF21400C17DA
1
10
100
1000
10000
P
G
P
CODE
L
W
T
Dimensions
2.00±0.20 1.25±0.20 0.80±0.15
CODE
G
P
R
≥0.01
Dimensions
0.40±0.30 0.30±0.20
T
Frequency (MHz)
Recommended Land Pattern
(Unit: mm)
Packaging Specification
• Taping (3,000/ reel)
Taping Direction (W)
(Unit: mm)
4.0
W (Standard)
Direction of Feed
CODE
T
Dimensions
3.20
W
2.30
R
1.00
C
1.20
P
0.80
Q
0.40
S
0.60
D
0.3 to 0.4
U
2.00
8.0
EMI Filters
KNF21 Series
<Impedance Matching Free>
• Stable attenuation against impedance change
• Good impedance matching without ringing
or distortion even at the time of IC ON/ OFF
and pattern layout change
Output Waveform (Clock frequency 25MHz)
R
LC filter
KNF21100
1MΩ
Test circuit
300Ω
<No Ringing>
Excellent Impedance Matching
KNF series
Output waveform
LC filter
Output waveform
No filter
Output waveform
• Wide attenuation up to high frequency range
without distortion
Attenuation Bandwidth
KNF21100
LC Filter (T-Type)
120
Spectrum att. (dBuV)
100
80
60
40
25
125 225 325 425 525 625 725 825 925
Frequency (MHz)
Filter passed
Test Circuit