Ferrites
and
Accessories
Ring Cores
Ring cores with the new blue epoxy coating from Siemens Matsushita Components
Ring Cores
Ring cores are firmly established in a large variety of advanced equipment and systems in electrical
and electronic engineering. In telecommunications they are found in interface transformers for ISDN
applications and in chokes for data and signal lines. EMC solutions with input and output chokes in
switch-mode power supplies are just as dependent on ring cores as the filters of frequency converters used in electric drives for traction applications and elevators. Lighting engineering needs them
too – ring cores in drive transformers for power transistors in electronic ballasts have long been
state of the art.
Core point: benefits that pay off
Ring cores offer exceptional advantages compared to other types of core, advantages that are indispensable for special requirements. They include in particular high inductance for small space
needs, low parasitic capacitance and – because of the smaller number of turns – the low ohmic resistance of chokes and transformers. A further benefit is that ring cores have low magnetic leakage.
New: coating made to measure
We offer a wide selection of uncoated and coated ring cores. The type of coating depends on the
materials used in different size categories. We work with the following variants: parylene (Galxyl) is
used for small diameter (< 10 mm) ring cores, polyamide is the material for ring core diameters from
4 to 30 mm.
For ring cores of larger diameters and those of high-permeablility materials (e.g. T46), we have a
new development called blue epoxy coating. This is an electrostatically deposited powder coating
exhibiting decisive advantages compared to conventional polyamide coating:
●
●
●
●
No drop in AL unlike uncoated cores of high-permeability materials (T38 and T46)
Much higher voltage strength
Noticeably higher mechanical strength
Substantially higher temperature resistance (up to 200 °C)
In future we will make general use of the advantages of epoxy coating for all cores ≥ 30 mm in diameter. It will also be offered as a special coating for cores of other diameters.
For further information contact the Siemens office near you or write us at
Siemens Matsushita Components GmbH & Co. KG
Marketing Kommunikation
Postfach 801709
D-81617 München
Internet: http://www.siemens.de/pr/index.htm
Siemens Matsushita Components
3.97
3
Ring Cores
● Our product line includes a wide range of ring cores with finely graded diameters ranging from
2,5 to 200 mm (see overview of available types). Other core heights can be supplied on request.
All cores are available in the usual materials.
Ring cores are available in different coating versions, thus offering the appropriate solution for
every application. The coating not only offers protection for the edges but also provides an
insulation function.
The following test setup is used to test the dielectric strength of the insulating coating: A copper
ring is pressed to the top edge of the ring. It touches the ferrite ring at the edges (see diagram).
The test duration is 2 seconds; the test voltages specified in the table are minimum values:
Ferrite ring
Urms
Metal poles
Core size
Urms
R 4 thru R 10
R 12,5 thru R 20
> R 20
1,0 kV
1,5 kV
2,0 kV
For cores with high permeability, increased spread of the AL values of several percent must be expected due to the polyamide coating (K version). This effect can be avoided by using an epoxy resin
coating (L version).
For small ring cores, we have introduced a parylene coating (Galxyl) which features a low coating
thickness and high dielectric strength.
● Ring cores are used primarily for pulse and broadband transformers, baluns and chokes. Owing
to the magnetically closed circuit, high flux densities can be achieved at small volume. Magnetic
leakage is negligible.
● Ring cores are also increasingly used for power applications. Here, the typical values for ampli-
tude permeability and power loss, as summarized in the section on SIFERRIT materials (Data
Book "Ferrites and Accessories", 1997), are applicable to the special power materials.
● In the list of preferred types, the AL1min value (measurement conditions 320 mT, 100 °C, 10 kHz)
is also specified for power applications, in addition to a limiting value for power loss under the
relevant measurement conditions. This provides a guarantee of the minimum amplitude permeability.
● Characteristic data for cores not included among the preferred types are available on request.
Versions
Version
Ordering code
● Uncoated
B64290-A...
● Coated with polyamide; thickness of coating approx. 0,2 to 0,4 mm
B64290-K...
● Coated with parylene; thickness of coating approx. 10 to 15 μm,
B64290-P...
standard coating for small cores (≤ R 4)
● Coated with epoxy resin; thickness of coating approx. 0,15 to 0,3 mm,
B64290-L...
coating for cores ≥ R 30
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Ring Cores
Application: Ring cores to suppress line interference
With the ever-increasing use of electrical and electronic equipment, it becomes increasingly important to be able to ensure that all facilities will operate simultaneously in the context of electromagnetic compatibility (EMC) without interfering with each others’ respective functions. The EMC legislation which came into force at the beginning of 1996 applies to all electrical and electronic products
marketed in the EU, both new and existing ones. So the latter may have to be modified so that they
are neither susceptible to electromagnetic interference, nor emit spurious radiation. Ferrite cores
are ideally suited for this purpose since they are able to suppress interference over a wide frequency range.
At frequencies above 1 MHz, ferrite rings slipped over a conductor lead to an increase in the impedance of this conductor. The real component of this impedance absorbs the interference energy.
A ferrite material´s suitability for suppressing interference within a specific frequency spectrum depends on its magnetic properties, which vary with frequency. Before the right material can be selected, the impedance lZl must be known as a function of frequency.
The curve of impedance as a function frequency is characterized by the sharp increase in loss at
resonance frequency.
Measurement results:
The measurements shown here were made at room temperature (23 ± 3 °C) using an HP 4191A
RF impedance analyzer with a flux density of B ≤ 1 mT.
The maximum of the impedance curve shifts to lower frequencies as the number of turns increases;
this is due to the capacitive effect of the turns (figure 1, using R25/15 as an example).
Figure 1
For direct comparison of the typical suppression characteristics of differenct ferrite materials, the
impedance curves were normalized using the equation lZ l n = lZ l / N 2 x Σ (le / Ae); the geometry
factor was calculated on the basis of the core dimensions (figure 2).
These normalized impedance curves are guide values, mostly measured using ring core R 10 with
a number of turns N = 1 (wire diameter 0,7 mm); they may vary slightly, depending on the geometry.
Siemens Matsushita Components
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Ring Cores
Figure 2
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Siemens Matsushita Components
Ring Cores
Ring cores are also available in split versions, which can easily be clipped onto cables. The residual
air gap inevitable in the reassembled ferrite ring affects its impedance characteristic only slightly in
the upper frequency range (figure 3, using R25/15 as an example).
Integral core
Split core
Figure 3
The residual air gap has a positive effect on performance with dc biasing because magnetic saturation is not reached until higher signal levels (figure 4, using R25/15 as an example).
Split core
Integral core
Figure 4
Siemens Matsushita Components
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Ring Cores
Overview of available types
Type
Dimensions
da1)
di1)
mm
mm
R 2,5
2,5 ± 0,12
1,5 ± 0,1
R 3,0
R 3,9
3,05 ± 0,2
3,94 ±0,12
1,27 ± 0,2
2,24 ±0,12
R 3,9/2
R 4,0
3,94 ±0,12
4,0 ± 0,12
(4,5 max)
2,24 ±0,12
2,4 ± 0,12
(1,9 min)
R 5,8
5,84 ±0,12
(6,36 max)
5,84 ±0,12
(6,36 max)
3,05 ±0,12
(2,53 min)
3,05 ±0,12
(2,53 min)
R 6,3
6,3 ± 0,15
(7,25 max)
3,8 ± 0,12
(2,85 min)
R 9,5/2
9,53 ±0,19
(10,5 max)
4,75 ±0,12
(3,8 min)
R 9,5
9,53 ±0,19
(10,5 max)
R 10
10,0 ± 0,2
(11,0 max)
4,75 ±0,12
(3,8 min)
6,0 ± 0,15
(5,05 min)
R 12,5
12,5 ± 0,3
(13,6 max)
13,3 ± 0,3
(14,4 max)
14,0 ± 0,3
(15,1 max)
7,5 ± 0,2
(6,5 min)
8,3 ± 0,3
(7,2 min)
9,0 ± 0,25
(7,95 min)
15,0 ± 0,5
(16,3 max)
10,4 ± 0,4
(9,2 min)
R 5,8/3
R 13,3
R 14
R 15
h1)
mm
1,0 ± 0,1
1,27 ± 0,2
1,3 ± 0,12
2,0 ± 0,12
1,6 ± 0,1
(2,1 max)
1,52 ±0,12
(2,05 max)
3,0 ± 0,12
(3,55 max)
2,5 ± 0,12
(3,4 max)
2,0 ± 0,1
(2,9 max)
3,17 ±0,15
(4,1 max)
4,0 ± 0,15
(4,95 max)
5,0 ± 0,15
(5,95 max)
5,0 ± 0,15
(5,95 max)
5,0 ± 0,2
(6,0 max)
5,3 ± 0,3
(6,4 max)
Magnetic characteristics
le
Ae
Σl/A
mm-1
mm
mm2
Approx.
weight
g
12,30
6,02
0,49
5,65
8,56
5,99
9,21
1,06
1,08
5,56
7,69
9,21
9,63
1,66
1,25
Ve
mm3
3,0
6,4
9,9
15,3
12,0
6,36
13,03
2,05
26,7
0,1
3,22
13,03
4,04
52,6
0,3
4,97
15,21
3,06
46,5
0,2
4,51
20,72
4,59
95,1
0,5
2,85
20,72
7,28
151
0,8
3,07
24,07
7,83
188
0,9
2,46
30,09
12,23
368
1,8
2,67
32,70
12,27
401
1,8
2,84
34,98
12,30
430
2,0
3,24
39,02
12,05
470
2,4
0,02
0,04
0,05
0,07
0,06
1) Values in parentheses apply to coated cores, ring cores made of NiZn ferrite may exceed the specified dimensions by up to 5 %
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Siemens Matsushita Components
Ring Cores
Type
Dimensions
da1)
di1)
mm
mm
R 16
16,0 ± 0,4
(17,2 max)
9,6 ± 0,3
(8,5 min)
R 17
17,0 ± 0,4
(18,2 max)
10,7 ± 0,3
(9,6 min)
R 20/7
20,0 ± 0,4
(21,2 max)
22,1 ± 0,4
(23,3 max)
22,6 ± 0,4
(23,8 max)
10,0 ±0,25
(8,7 min)
13,7 ± 0,3
(12,6 min)
14,7 ± 0,2
(13,7 min)
R23/9
22,6 ± 0,4
(23,8 max)
14,7 ± 0,2
(13,7 min)
R 25/10
25,3 ± 0,7
(26,8 max)
14,8 ± 0,5
(13,5 min)
R 25/15
25,3 ± 0,7
(26,8 max)
14,8 ± 0,5
(13,5 min)
R 25/20
25,3 ± 0,7
(26,8 max)
29,5 ± 0,7
(31,0 max)
30,5 ± 1,0
(32,3 max)
14,8 ± 0,5
(13,5 min)
19,0 ± 0,5
17,7 min
20,0 ± 0,6
(18,2 min)
34,0 ± 0,7
(35,5 max)
R 34/12,5 34,0 ± 0,7
(35,5 max)
R 36
36,0 ± 0,7
(37,5 max)
20,5 ± 0,5
(19,2 min)
20,5 ± 0,5
(19,2 min)
23,0 ± 0,5
(21,7 min)
R 40
40,0 ±1,0
(41,8 max)
24,0 ± 0,7
(22,5 min)
R 42
41,8 ± 1,0
(43,6 max)
26,2 ± 0,6
(24,8 min)
R 50
50,0 ± 1,0
(51,8 max)
30,0 ± 0,7
(28,5 min)
R 58
58,3 ± 1,0
(60,1 max)
40,8 ± 0,8
(39,2 min)
R 22
R23/8
R 29
R 30
R 34/10
h1)
mm
6,3 ± 0,2
(7,3 max)
6,8 ± 0,2
(7,8 max)
7,0 ± 0,4
(8,2 max)
6,35 ±0,3
(7,4 max)
7,6 ± 0,2
(8,6 max)
9,2 ± 0,2
(10,2 max)
10,0 ± 0,2
(11,0 max)
15,0 ± 0,4
16,2 max)
20,0 ± 0,5
(21,3 max)
14,9 ± 0,4
(16,1 max)
12,5 ± 0,4
(13,7 max)
10,0 ± 0,3
(11,1 max)
12,5 ± 0,3
(13,6 max)
15,0 ± 0,4
(16,2 max)
16,0 ± 0,4
(17,2 max)
12,5 ± 0,3
(13,6 max)
20,0 ± 0,5
(21,3 max)
17,6 ± 0,4
(18,8 max)
Magnetic characteristics
le
Ae
Σl/A
mm-1
mm
mm2
Approx.
weight
g
1,95
38,52
19,73
Ve
mm3
760
2,00
42,0
21,04
884
4,4
1,30
43,55
33,63
1465
7,6
2,07
54,15
26,17
1417
6,8
1,92
56,82
29,56
1680
8,1
1,59
56,82
35,78
2033
9,8
1,17
60,07
51,26
3079
16
0,78
60,07
76,89
4619
24
0,59
60,07
102,5
6157
33
0,96
73,78
76,98
5680
27
1,19
77,02
64,66
4980
25
1,24
82,06
66,08
5423
27
0,99
82,06
82,60
6778
33
0,94
89,65
95,89
8597
43
0,77
96,29
125,3
12070
61
1,08
103,0
95,75
9862
48
0,62
120,4
195,7
23560
118
1,00
152,4
152,4
23230
115
3,7
1) Values in parentheses apply to coated cores, ring cores made of NiZn ferrite may exceed the specified dimensions by up to 5 %
Siemens Matsushita Components
3.97
9
Ring Cores
Type
Dimensions
da1)
di1)
mm
mm
R 100
102,0 ± 2,0 65,8 ± 1,3
(104,8 max) (63,7 min)
R 140
140,0 ± 3,0 103,0 ± 2,0
(143,8 max) (100,2 min)
R 200
202,0 ± 4,0 153,0 ± 3,0
(206,8 max) (149,2 min)
h1)
mm
15,0 ± 0,5
(16,3 max)
25,0 ± 1,0
(26,8 max)
25,0 ± 1,0
(26,8 max)
Magnetic characteristics
le
Ae
Σl/A
mm-1
mm
mm2
Approx.
weight
g
0,96
255,3
267,2
Ve
mm3
68220
0,82
375,8
458,9
172440 860
0,90
550,5
608,6
335030 1600
330
1) Values in parentheses apply to coated cores, ring cores made of NiZn ferrite may exceed the specified dimensions by up to 5 %
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Ring Cores
Preferred types 1)
Type
Mate- AL value
nH
rial
(1mT,
10 kHz, 25°C)
AL1min
nH
(320 mT,
N49: 200 mT,
10 kHz,
100 °C)
Power loss per core
(measurement
conditions)
Ordering
code
PU
B64290-
Pcs
R 2,5
N 30
T 38
T 38
440 ± 25%
1020 ± 30%
1020 +30/-40%
-P35-X830
-A35-X38
-P35-X38
40000
R4
K1
M 33
N 30
T 38
T 38
T46
K1
M 33
N 492)
13 ± 25%
123 ± 25%
700 ± 25%
1630 ± 30%
1630 +30/-40%
2450 +30/-30%
-A36-X1
-A36-X33
-K36-X830
-A36-X38
-P36-X38
-A36-X46
16000
20 ± 25%
190 ± 25%
330 ± 25%
-A37-X1
-K37-X33
-K37-X49
4000
R 6,3
R 9,5 / 2
R 10
R 12,5
N 30
N 30
T38
T38
T46
K1
M33
N492)
250
< 6 mW
(50 mT/500 kHz/100°C)
1090 ± 25%
1090 ± 25%
2530 ± 30%
2530 +30/-40%
4180 ± 30%
-A37-X830
-K37-X830
-A37-X38
-K37-X38
33 ± 25%
308 ± 25%
530 ± 25%
-A38-X1
-K38-X33
-K38-X49
1000
3000
3000
-A38-X830
-K38-X830
-K38-X38
1000
3000
3000
-K44-X49
< 45 mW
(50 mT/500 kHz/100°C)
-K44-X27
< 70 mW
(200 mT/25 kHz/100°C)
-K44-X67
< 280 mW
(200 mT/100 kHz/100°C)
-A44-X830
-K44-X830
-A44-X35
-K44-X35
1500
-A681-X46
410
< 23 mW
(50 mT/500 kHz/100°C)
1760 ± 25%
1760 ± 25%
4090 +30/-40%
N30
N30
T38
N 492)
660 ± 25%
510
N27
1020 ± 25%
460
N 67
1070 ± 25%
460
N30
N30
T 35
T 35
2200 ± 25%
2200 ± 25%
3060 ± 25%
3060 +25/-30%
Siemens Matsushita Components
3.97
1500
1500
500
1500
500
1500
11
Ring Cores
Type
Mate- AL value
rial
nH
(1mT,
10 kHz, 25°C)
AL1min
nH
(320 mT,
N49: 200 mT,
10 kHz,
100 °C)
Power loss per core
(measurement
conditions)
Ordering
code
PU
B64290-
Pcs
1) The preferred core types are available at short notice. Other cores on request.
2) Preliminary data
R 16
N 491) 840 ± 25%
640
-K45-X49
< 95 mW
(50 mT/500 kHz/100°C)
< 140 mW
-K45-X27
(200 mT/25 kHz/100°C)
< 500 mW
-K45-X67
(200 mT/100 kHz/100°C)
-K45-X830
-A45-X35
-K45-X35
-A45-X38
-K45-X38
< 280 mW
-K632-X27
(200 mT/25 kHz/100°C)
< 1,2 W
-K632-X67
(200 mT/100 kHz/100°C)
-A632-X830
-K632-X830
-A632-X35
-K632-X35
-K632-X38
2000
< 250 mW
(200 mT/25 kHz/100°C)
300
N27
1290 ± 25%
580
N67
1350 ± 25%
580
N30
T35
T35
T38
T38
N 27
2770 ± 25%
3870 ± 25%
3870 +25/-30%
6440 ± 30%
6440 +30/-40%
870
1930 ± 25%
N 67
2030 ± 25%
N 30
N 30
T 35
T 35
T 38
4160 ± 25%
4160 ± 25%
5000 ± 25%
5000 +25/-30%
8500 +30/-40%
N 27
1210 ± 25%
N30
T 35
T 35
2610 ± 25%
3200 ± 25%
3200 +25/-30%
N 27
2150 ± 25%
970
N 67
2260 ± 25%
970
N 30
N 30
T 35
T 35
4620 ± 25%
4620 ± 25%
5400 ± 25%
5400 +25/-30%
N 30
4360 ± 25%
-L58-X830
225
R 34/12,5 N 30
5460 ± 25%
-L48-X830
225
R 20/7
R 22
R 25/10
R 34/10
12
870
550
-K638-X27
2000
2000
2000
1000
2000
1000
2000
1000
1000
500
1000
500
1000
1000
-K638-X830 300
-A638-X35 500
-K638-X35 300
-K618-X27 500
< 580 mW
(200 mT/25 kHz/100°C)
-K618-X67
< 2,4 W
(200 mT/100 kHz/100°C)
-A618-X830
-K618-X830
-A618-X35
-K618-X35
3.97
500
400
500
400
500
Siemens Matsushita Components
Ring Cores
Type
Mate- AL value
nH
rial
(1mT,
10 kHz, 25°C)
AL1min
nH
(320 mT,
N49: 200 mT,
10 kHz,
100 °C)
Power loss per core
(measurement
conditions)
Ordering
code
PU
B64290-
Pcs
1) Preliminary data
N 27
2670 ± 25%
1200
N 67
2810 ± 25%
1200
N 30
N 30
5750 ± 25%
5750 ± 25%
< 1,6 W
-L674-X27 200
(200 mT/25 kHz/100°C)
< 5,9 W
-L674-X67
(200 mT/100 kHz/100°C)
-A674-X830
-L674-X830
N 30
N 30
N 30
N 30
7000 ± 25%
7000 ± 25%
5000 ± 25%
5000 ± 25%
-A659-X830 80
-L659-X830
-A22-X830 192
-L22-X830
R 50
N 30
N 30
8700 ± 25%
8700 ± 25%
-A82-X830
-L82-X830
64
R 58
R 100
N 30
N 30
5400 ± 25%
5500 ± 25%
-L40-X830
-A84-X830
90
24
R 140
R 200
N 30
N 30
6200 ± 25%
5500 ± 30%
-A705-X830 4
-A711-X830 2
R 36
R 40
R 42
Siemens Matsushita Components
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13
Ring Cores
Published by Siemens Matsushita Components GmbH & Co. KG
Marketing Kommunikation, Postfach 80 17 09, D-81617 München
© Siemens Matsushita Components 1997. All Rights Reserved.
As far as patents or other rights of third parties are concerned, liability is only assumed for components per se, not for applications, processes and circuits implemented within components or
assemblies.
The information describes the type of component and shall not be considered as assured
characteristics.
Terms of delivery and rights to change design reserved.
This brochure replaces the previous edition.
For questions on technology, prices and delivery please contact the Sales Offices of Siemens AG,
Passive Components and Electron Tubes Group, in the Federal Republic of Germany or the international Siemens Companies and Representatives.
Due to technical requirements components may contain dangerous substances. For information on
the type in question please also contact one of our Sales Offices.
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