EMI Filters
KNF21 Series
RoHS Compliant
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
Applications
• PCs, Laser Printers, Cellular Phone,
Clock Data Lines for LCD Display
• High Speed Video Signal Circuits and
Interface Circuits
• High Speed Digital Circuits
How to Order
KNF 21 100 C65 DA 3T S
①②③ ④ ⑤⑥⑦
①Series
②Size Code
21 2012 (EIA: 0805)
③Cut off Frequency
025 25MHz 200 200MHz
050 50MHz 400 400MHz
100 100MHz
④Capacitance
C17 17pF C130 130pF
C33 33pF C235 235pF
C65 65pF
⑤Application
DA Digital Circuit in General
⑥Packaging
3T T&R: 3000 pcs. (Std.)
⑦ Termination
SStd.
Specifications
Part Number
Cut off
Frequency
Capacitance
(+50/ −20%)
Attenuation
(Typical)
Rated
Current
Rated
Voltage
Operating
Temperature
KNF21025C235DA3TS
25MHz 235pF
200 to 600MHz (@20dB) 150mA 25VDC
−25 to +85°C
KNF21050C130DA3TS
50MHz 130pF
350 to 850MHz (@20dB) 150mA 25VDC
KNF21100C65DA3TS
100MHz 65pF
450 to 950MHz (@20dB) 150mA 25VDC
KNF21200C33DA3TS
200MHz 33pF
700 to 1200MHz (@20dB) 150mA 25VDC
KNF21400C17DA3TS
400MHz 17pF
900 to 1400MHz (@20dB) 150mA 25VDC
• Storage condition
Temperature: −10 to +45°C
Humidity: 45 to 75%RH
Dimensions (Unit: mm)
Input Direction Mark
L
W
T
GP P
IN OUT
R
CODE L W T
Dimensions
2.00±0.20 1.25±0.20 0.80±0.15
CODE G P R
Dimensions
0.40±0.30 0.30±0.20 ≥0.01
Attenuation Characteristics
KNF21 Series
Frequency (MHz)
−50
−40
−30
−20
−10
0
10
1 10 100 1000 10000
Attenuation (dB)
KNF21025C235DA
KNF21050C130DA
KNF21100C65DA
KNF21200C33DA
KNF21400C17DA
Recommended Land Pattern (Unit: mm)
0
#
4
3
1
4HROUGH(OLE
$
2ESIST
2ESIST
2
7
#ONDUCTOR
5
Packaging Specification
• Taping (3,000/ reel) (Unit: mm)
W (Standard)
Taping Direction (W)
Direction of Feed
4.0
8.0
CODE T W R C P Q S D U
Dimensions 3.20 2.30 1.00 1.20 0.80 0.40 0.60 0.3 to 0.4 2.00
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
Test circuit
4ESTPOINT
,6#
FILTER
,6#
2
-(Z
Output Waveform (Clock frequency 25MHz)
R LC filter KNF21100
1MΩ
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
Test Circuit
4ESTPOINT
FILTER,6#
MM
-(Z
Attenuation Bandwidth
KNF21100
&REQUENCY-(Z
3PECTRUMATTD"U6
/RIGINAL
&ILTERPASSED
LC Filter (T-Type)
25
120
100
80
60
40
925825725625525
Frequency (MHz)
Spectrum att. (dBuV)
425325225125
/RIGINAL
Filter passed
