Series BF
Split Ferrite Suppressors for Round Cables
SUPPRESSORS
2/2002
PAG E
111
www.delevan.com
E-mail: apisales@delev an.com
270 Quaker Rd., East Aurora NY 14052 • Phone 716-652-3600 • Fax 716-652-4814
Electronic cables and wires, by virtue of their length-to-width
ratios , are perfect natural antennas. In the presence of high
speed microprocessor signals,
cables will conduct, r adiate
and/or receive unwanted
high frequency interf ering
signals. Radio interference
sources usually radiate their RFI
pow er at frequencies abo ve 30
MHz by way of the
main cabling, which
acts as an antenna.
Control of radio
interf erence can be
assured by proper
placement of an insertion
loss de vice , such as a ferrite
suppressor. Any device used to
block an RFI signal between its source and a receiv er is an
electromagnetic interf erence (EMI) shield. The measure of
this ability to attenuate RFI is shielding effectiveness , "SE",
which is e xpressed in decibels , "dB", the r atio of field
strength on one side of the shield to the other side.
One of the most versatile and cost effective shielding
methods that can be used
toda y is the API Delevan
bisected f errite cable snap
assembly. The bisected
styling, or f amiliar
clamshell enclosure
design off ers the ultimate
in adaptability. The RF
absorbing and material
interacts directly with
unwanted high frequency energy and
dissipates it eff ectively while allowing data signals to pass
unimpeded.
Bisected f errites have a concentrated, homogeneous
magnetic structure with high permeability. These are
consistently stable at +20°C to +60°C and provide RF
suppression without eddy current losses.
AIR GAP EFFECT
The air gap in bisected f errites actually e xtends current
carrying capabilities with only an extremely small reduction
in impedance versus solid ferrites of the same size. The gap
is magnetically insignificant while it is electrically significant
as a discontinuation, thereb y accommodating more current.
RF SOURCE AUXILIARY
EQUIPMENT
OR PO WER SOURCE
OR
RF SOURCE RF SOURCE
RF SOURCE
RF SOURCE OR
POSITION OF SUPPRESSOR
POSITION OF SUPPRESSOR The suppressor should
normally be located close to the cable termination where it exits
the enclosure. Where a cab le connects tw o enclosures
containing RF sources, a suppressor on each end ma y be
required. F or circuits within an enclosure, a position close to the
RF is best. How e v er, other locations along the circuit ma y w ork
as well.
Material and U .L. Data API-1 Material, see characteristics
and inf ormation on page 118
SUPPRESSORS
11/2002
PAG E
112
www.delevan.com
E-mail: apisales@delev an.com
270 Quaker Rd., East Aurora NY 14052 • Phone 716-652-3600 • Fax 716-652-4814
PART NUMBER
IMPED-
ANCE
(OHMS)
*
UNITS
AB
DIMENSIONS
Inches ± 0.04; mm ± 1.0
CDL
BODY TYPE
25 MHz
100 MHz
BODY TYPE E
BODY TYPE D
BODY TYPE C
BODY TYPE B
BODY TYPE A
Series BF Split Ferrite
Suppressors for Round Cables
155
136
171
112
96
139
85
82
51
50
42
126
41
257
250
325
172
154
191
157
146
103
107
94
174
95
1.30
33.0
1.28
32.6
1.28
32.5
1.37
35.0
0.98
25.0
0.98
25.0
1.14
29.0
0.98
25.0
0.69
17.7
0.77
19.7
0.66
16.8
1.22
31.0
0.60
15.2
—
—
—
—
—
—
—
—
0.94
24.0
1.01
25.8
0.90
23.0
1.38
35.2
0.84
21.5
0.51
13.0
0.39
10.0
0.25
6.5
0.35
9.0
0.19
5.0
0.13
3.5
0.22
5.6
0.15
4.0
0.45
11.4
0.32
8.15
0.32
8.15
0.35
9.0
0.59
15.0
1.20
30.5
0.91
23.3
0.76
19.5
0.77
19.7
0.51
13.0
0.51
13.0
0.61
15.7
0.57
14.7
—
—
—
—
—
1.16
29.6
0.87
22.3
0.70
17.8
0.70
18.0
0.46
11.7
0.46
11.7
0.57
14.5
0.50
12.8
1.20
30.5
0.84
21.5
0.84
21.5
0.73
18.6
1.24
31.5
A
A
A
B
B
B
C
C
D
D
D
E
D
in.
mm
in.
mm
in.
mm
in.
mm
in.
mm
in.
mm
in.
mm
in.
mm
in.
mm
in.
mm
in.
mm
in.
mm
in.
mm
Physical Parameters
Material and U .L. Data API-1 Material, see characteristics and
inf ormation on page 118.
*Note Impedance is typical, based on 1⁄2 turn (4.0") 18 A WG
wire. Impedance measurement using HP4191A.
Color Black; Special colors Av ailable for bases on a
non-cancellable, non returnab le basis C = Cream;
W = White; Gr = Grey
U .L. Recognized
All plastic and adhesive components use U.L. Recogniz ed
materials with Flammability Ratings of UL94V-0, UL-510 or
UL-746C
SEE Z vs. f GRAPHS ON NEXT PAGE
SERIES BF - FOR ROUND CABLES
BF2930
BF2223
BF1719
BF1835
BF1125-5
BF1125-3
BF1429
BF1225
BF3024
BF2125
BF2123
BF1835-9
BF3121
Series BF
Split Ferrite Suppressors for Round Cables
SUPPRESSORS
2/2002
PAG E
113
www.delevan.com
E-mail: apisales@delev an.com
270 Quaker Rd., East Aurora NY 14052 • Phone 716-652-3600 • Fax 716-652-4814
1
FREQUENCY (MHz)
IMPED ANCE (OHMS)
10
10 100 1000
100
1000
11 10 100 10001 10 100 1000
10
100
1000
1
BF2125 BF2123
BF2930 BF2223
BF1719 BF1835BF1835-9
BF1429
BF3024
1
10
10 100 1000
100
1000
11 10 100 10001 10 100 1000
10
100
1000
1
1
10
10 100 1000
100
1000
11 10 100 10001 10 100 1000
10
100
1000
1
1
10
10 100 1000
100
1000
11 10 100 10001 10 100 1000
10
100
1000
1
IMPED ANCE vs. FREQ UENCY
10
100
1000
11 10 100 1000
FREQUENCY (MHz)
BF1125-5 BF1125-3BF1225
BF3121
Additional Information on Preceding Pages
Note Impedance is typical, based on 1⁄2 turn (4.0") 18 A WG wire .
Impedance measurement using HP4191A
For more detailed graphs, contact factory
