Ferrites
and
Accessories
Ring Cores
Ring cores with the new blue epoxy coating from Siemens Matsushita Components
Siemens Matsushita Components 3.97 3
Ring cores are firmly establ ished in a large variety of advanced equ ipment 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 conver-
ters 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 in-
dispensable 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 re-
sistance of chokes and tran sformers. 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 dia meter (< 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
A
L 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 dia-
meter. 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
Ring Cores
4 3.97 Siemens Matsushita Components
●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:
For cores with hig h per me ability, increased spread of the
A
L values of several percent must be ex-
pected 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
A
L1min value (mea surement 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 perme-
ability.
●Characteristic data for cores not included among the preferred types are available on request.
Versions
Version Ordering code
●Uncoated
●Coated with polyamide; thickness of coating approx. 0,2 to 0,4 mm
●Coated with parylene; thickness of coating approx. 10 to 15 μm,
standard coating for small cores (≤ R 4)
●Coated with epoxy resin; thickness of coating approx. 0,15 to 0,3 mm,
coating for cores ≥ R 30
B64290-A...
B64290-K...
B64290-P...
B64290-L...
Core size
U
rms
R 4 thru R 10
R 12,5 thru R 20
> R 20
1,0 kV
1,5 kV
2,0 kV
Ferrite ring
Metal poles
U
rms
Ring Cores
Siemens Matsushita Components 3.97 5
Application: Ring cores to suppress line interference
With the ever-increasing use of electrical and electronic equipment, it becomes increasingly impor-
tant to be able to ensure that all facilities will operate simultaneously in the context of electromag-
netic compatibility (EMC) without interfering with each others’ respective functions. The EMC legis-
lation which came into force at the beginning of 1996 applies to all electrical and electronic products
marketed in the EU, both ne w and existing ones. So the latter may have to be mo dified 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 frequen-
cy range.
At frequencies above 1 MHz, ferrite rings slipped over a conductor lead to an increase in the imped-
ance 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 de-
pends on its magnetic properties, which vary with frequency. Before the right material can be se-
lected, 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 imp edance curve shifts to lo wer frequencies as the number of tur ns 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 l
Z
ln = l
Z
l /
N
2 x Σ (
l
e /
A
e); the geometry
factor was calculated on the basis of the core dimensions (figure 2).
These normalized im pe da nce cu rve s are guid e val ues, mo stly mea sure d usi ng ring co re R 10 with
a number of turns N = 1 (wire diameter 0,7 mm); they may vary slightly, depending on the geometry.
Ring Cores
6 3.97 Siemens Matsushita Components
Figure 2
Ring Cores
Siemens Matsushita Components 3.97 7
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 up per freq uency range (figure 3, us ing R25/ 15 as an example).
Figure 3
The residual air gap has a positive effect on performance with dc biasing because magnetic satu-
ration is not reached until higher signal levels (figure 4, using R25/15 as an example).
Figure 4
Integral core
Split core
Split core
Integral core
Ring Cores
8 3.97 Siemens Matsushita Components
Overview of available types
Type Dimensions Magnetic characteristics Approx.
d
a1)
mm
d
i1)
mm
h
1)
mm Σ
l/A
mm-1
l
e
mm
A
e
mm2
V
e
mm3weight
g
R 2,5 2,5 ± 0,12 1,5 ± 0,1 1,0 ± 0,1 12,30 6,02 0,49 3,0 0,02
R 3,0 3,05 ± 0,2 1,27 ± 0,2 1,27 ± 0,2 5,65 5,99 1,06 6,4 0,04
R 3,9 3,94 ±0,12 2,24 ±0,12 1,3 ± 0,12 8,56 9,21 1,08 9,9 0,05
R 3,9/2 3,94 ±0,12 2,24 ±0,12 2,0 ± 0,12 5,56 9,21 1,66 15,3 0,07
R 4,0 4,0 ± 0,12
(4,5 max) 2,4 ± 0,12
(1,9 min) 1,6 ± 0,1
(2,1 max) 7,69 9,63 1,25 12,0 0,06
R 5,8 5,84 ±0,12
(6,36 max) 3,05 ±0,12
(2,53 min) 1,52 ±0,12
(2,05 max) 6,36 13,03 2,05 26,7 0,1
R 5,8/3 5,84 ±0,12
(6,36 max) 3,05 ±0,12
(2,53 min) 3,0 ± 0,12
(3,55 max) 3,22 13,03 4,04 52,6 0,3
R 6,3 6,3 ± 0,15
(7,25 max) 3,8 ± 0,12
(2,85 min) 2,5 ± 0,12
(3,4 max) 4,97 15,21 3,06 46,5 0,2
R 9,5/2 9,53 ±0,19
(10,5 max) 4,75 ±0,12
(3,8 min) 2,0 ± 0,1
(2,9 max) 4,51 20,72 4,59 95,1 0,5
R 9,5 9,53 ±0,19
(10,5 max) 4,75 ±0,12
(3,8 min) 3,17 ±0,15
(4,1 max) 2,85 20,72 7,28 151 0,8
R 10 10,0 ± 0,2
(11,0 max) 6,0 ± 0,15
(5,05 min) 4,0 ± 0,15
(4,95 max) 3,07 24,07 7,83 188 0,9
R 12,5 12,5 ± 0,3
(13,6 max) 7,5 ± 0,2
(6,5 min) 5,0 ± 0,15
(5,95 max) 2,46 30,09 12,23 368 1,8
R 13,3 13,3 ± 0,3
(14,4 max) 8,3 ± 0,3
(7,2 min) 5,0 ± 0,15
(5,95 max) 2,67 32,70 12,27 401 1,8
R 14 14,0 ± 0,3
(15,1 max) 9,0 ± 0,25
(7,95 min) 5,0 ± 0,2
(6,0 max) 2,84 34,98 12,30 430 2,0
R 15 15,0 ± 0,5
(16,3 max) 10,4 ± 0,4
(9,2 min) 5,3 ± 0,3
(6,4 max) 3,24 39,02 12,05 470 2,4
1) Values in parentheses apply to coated cores, ring cores made of NiZn ferrite may exceed the specified dimensions by up to 5 %
Ring Cores
Siemens Matsushita Components 3.97 9
R 16 16,0 ± 0,4
(17,2 max) 9,6 ± 0,3
(8,5 min) 6,3 ± 0,2
(7,3 max) 1,95 38,52 19,73 760 3,7
R 17 17,0 ± 0,4
(18,2 max) 10,7 ± 0,3
(9,6 min) 6,8 ± 0,2
(7,8 max) 2,00 42,0 21,04 884 4,4
R 20/7 20,0 ± 0,4
(21,2 max) 10,0 ±0,25
(8,7 min) 7,0 ± 0,4
(8,2 max) 1,30 43,55 33,63 1465 7,6
R 22 22,1 ± 0,4
(23,3 max) 13,7 ± 0,3
(12,6 min) 6,35 ±0,3
(7,4 max) 2,07 54,15 26,17 1417 6,8
R23/8 22,6 ± 0,4
(23,8 max) 14,7 ± 0,2
(13,7 min) 7,6 ± 0,2
(8,6 max) 1,92 56,82 29,56 1680 8,1
R23/9 22,6 ± 0,4
(23,8 max) 14,7 ± 0,2
(13,7 min) 9,2 ± 0,2
(10,2 max) 1,59 56,82 35,78 2033 9,8
R 25/10 25,3 ± 0,7
(26,8 max) 14,8 ± 0,5
(13,5 min) 10,0 ± 0,2
(11,0 max) 1,17 60,07 51,26 3079 16
R 25/15 25,3 ± 0,7
(26,8 max) 14,8 ± 0,5
(13,5 min) 15,0 ± 0,4
16,2 max) 0,78 60,07 76,89 4619 24
R 25/20 25,3 ± 0,7
(26,8 max) 14,8 ± 0,5
(13,5 min) 20,0 ± 0,5
(21,3 max) 0,59 60,07 102,5 6157 33
R 29 29,5 ± 0,7
(31,0 max) 19,0 ± 0,5
17,7 min 14,9 ± 0,4
(16,1 max) 0,96 73,78 76,98 5680 27
R 30 30,5 ± 1,0
(32,3 max) 20,0 ± 0,6
(18,2 min) 12,5 ± 0,4
(13,7 max) 1,19 77,02 64,66 4980 25
R 34/10 34,0 ± 0,7
(35,5 max) 20,5 ± 0,5
(19,2 min) 10,0 ± 0,3
(11,1 max) 1,24 82,06 66,08 5423 27
R 34/12,5 34,0 ± 0,7
(35,5 max) 20,5 ± 0,5
(19,2 min) 12,5 ± 0,3
(13,6 max) 0,99 82,06 82,60 6778 33
R 36 36,0 ± 0,7
(37,5 max) 23,0 ± 0,5
(21,7 min) 15,0 ± 0,4
(16,2 max) 0,94 89,65 95,89 8597 43
R 40 40,0 ±1,0
(41,8 max) 24,0 ± 0,7
(22,5 min) 16,0 ± 0,4
(17,2 max) 0,77 96,29 125,3 12070 61
R 42 41,8 ± 1,0
(43,6 max) 26,2 ± 0,6
(24,8 min) 12,5 ± 0,3
(13,6 max) 1,08 103,0 95,75 9862 48
R 50 50,0 ± 1,0
(51,8 max) 30,0 ± 0,7
(28,5 min) 20,0 ± 0,5
(21,3 max) 0,62 120,4 195,7 23560 118
R 58 58,3 ± 1,0
(60,1 max) 40,8 ± 0,8
(39,2 min) 17,6 ± 0,4
(18,8 max) 1,00 152,4 152,4 23230 115
1) Values in parentheses apply to coated cores, ring cores made of NiZn ferrite may exceed the specified dimensions by up to 5 %
Type Dimensions Magnetic characteristics Approx.
d
a1)
mm
d
i1)
mm
h
1)
mm Σ
l/A
mm-1
l
e
mm
A
e
mm2
V
e
mm3weight
g
Ring Cores
10 3.97 Siemens Matsushita Components
R 100 102,0 ± 2,0
(104,8 max) 65,8 ± 1,3
(63,7 min) 15,0 ± 0,5
(16,3 max) 0,96 255,3 267,2 68220 330
R 140 140,0 ± 3,0
(143,8 max) 103,0 ± 2,0
(100,2 min) 25,0 ± 1,0
(26,8 max) 0,82 375,8 458,9 172440 860
R 200 202,0 ± 4,0
(206,8 max) 153,0 ± 3,0
(149,2 min) 25,0 ± 1,0
(26,8 max) 0,90 550,5 608,6 335030 1600
1) Values in parentheses apply to coated cores, ring cores made of NiZn ferrite may exceed the specified dimensions by up to 5 %
Type Dimensions Magnetic characteristics Approx.
d
a1)
mm
d
i1)
mm
h
1)
mm Σ
l/A
mm-1
l
e
mm
A
e
mm2
V
e
mm3weight
g
Ring Cores
Siemens Matsushita Components 3.97 11
Preferred types 1)
Type Mate-
rial
A
Lvalue
nH
(1mT,
10 kHz, 25°C)
A
L1min
nH
(320 mT,
N49: 200 mT,
10 kHz,
100 °C)
Power loss per core
(measurement
conditions)
Ordering
code
B64290-
PU
Pcs
R 2,5 N 30
T 38
T 38
440 ± 25%
1020 ± 30%
1020 +30/-40%
-P35-X830
-A35-X38
-P35-X38
40000
R 4 K 1
M 33
N 30
T 38
T 38
T46
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
R 6,3 K 1
M 33
N 492)
N 30
N 30
T38
T38
20 ± 25%
190 ± 25%
330 ± 25%
1090 ± 25%
1090 ± 25%
2530 ± 30%
2530 +30/-40%
250 < 6 mW
(50 mT/500 kHz/100°C)
-A37-X1
-K37-X33
-K37-X49
-A37-X830
-K37-X830
-A37-X38
-K37-X38
4000
R 9,5 / 2 T46 4180 ± 30% -A681-X46
R 10 K1
M33
N492)
N30
N30
T38
33 ± 25%
308 ± 25%
530 ± 25%
1760 ± 25%
1760 ± 25%
4090 +30/-40%
410 < 23 mW
(50 mT/500 kHz/100°C)
-A38-X1
-K38-X33
-K38-X49
-A38-X830
-K38-X830
-K38-X38
1000
3000
3000
1000
3000
3000
R 12,5 N 492)
N27
N 67
N30
N30
T 35
T 35
660 ± 25%
1020 ± 25%
1070 ± 25%
2200 ± 25%
2200 ± 25%
3060 ± 25%
3060 +25/-30%
510
460
460
< 45 mW
(50 mT/500 kHz/100°C)
< 70 mW
(200 mT/25 kHz/100°C)
< 280 mW
(200 mT/100 kHz/100°C)
-K44-X49
-K44-X27
-K44-X67
-A44-X830
-K44-X830
-A44-X35
-K44-X35
1500
1500
1500
500
1500
500
1500
Ring Cores
12 3.97 Siemens Matsushita Components
1) The preferred core types are available at short notice. Other cores on request.
2) Preliminary data
R 16 N 491)
N27
N67
N30
T35
T35
T38
T38
840 ± 25%
1290 ± 25%
1350 ± 25%
2770 ± 25%
3870 ± 25%
3870 +25/-30%
6440 ± 30%
6440 +30/-40%
640
580
580
< 95 mW
(50 mT/500 kHz/100°C)
< 140 mW
(200 mT/25 kHz/100°C)
< 500 mW
(200 mT/100 kHz/100°C)
-K45-X49
-K45-X27
-K45-X67
-K45-X830
-A45-X35
-K45-X35
-A45-X38
-K45-X38
2000
2000
2000
2000
1000
2000
1000
2000
R 20/7 N 27
N 67
N 30
N 30
T 35
T 35
T 38
1930 ± 25%
2030 ± 25%
4160 ± 25%
4160 ± 25%
5000 ± 25%
5000 +25/-30%
8500 +30/-40%
870
870
< 280 mW
(200 mT/25 kHz/100°C)
< 1,2 W
(200 mT/100 kHz/100°C)
-K632-X27
-K632-X67
-A632-X830
-K632-X830
-A632-X35
-K632-X35
-K632-X38
1000
1000
500
1000
500
1000
1000
R 22 N 27
N30
T 35
T 35
1210 ± 25%
2610 ± 25%
3200 ± 25%
3200 +25/-30%
550 < 250 mW
(200 mT/25 kHz/100°C) -K638-X27
-K638-X830
-A638-X35
-K638-X35
300
300
500
300
R 25/10 N 27
N 67
N 30
N 30
T 35
T 35
2150 ± 25%
2260 ± 25%
4620 ± 25%
4620 ± 25%
5400 ± 25%
5400 +25/-30%
970
970
< 580 mW
(200 mT/25 kHz/100°C)
< 2,4 W
(200 mT/100 kHz/100°C)
-K618-X27
-K618-X67
-A618-X830
-K618-X830
-A618-X35
-K618-X35
500
500
400
500
400
500
R 34/10 N 30 4360 ± 25% -L58-X830 225
R 34/12,5 N 30 5460 ± 25% -L48-X830 225
Type Mate-
rial
A
Lvalue
nH
(1mT,
10 kHz, 25°C)
A
L1min
nH
(320 mT,
N49: 200 mT,
10 kHz,
100 °C)
Power loss per core
(measurement
conditions)
Ordering
code
B64290-
PU
Pcs
Ring Cores
Siemens Matsushita Components 3.97 13
1) Preliminary data
R 36 N 27
N 67
N 30
N 30
2670 ± 25%
2810 ± 25%
5750 ± 25%
5750 ± 25%
1200
1200
< 1,6 W
(200 mT/25 kHz/100°C)
< 5,9 W
(200 mT/100 kHz/100°C)
-L674-X27
-L674-X67
-A674-X830
-L674-X830
200
R 40 N 30
N 30 7000 ± 25%
7000 ± 25% -A659-X830
-L659-X830 80
R 42 N 30
N 30 5000 ± 25%
5000 ± 25% -A22-X830
-L22-X830 192
R 50 N 30
N 30 8700 ± 25%
8700 ± 25% -A82-X830
-L82-X830 64
R 58 N 30 5400 ± 25% -L40-X 8 30 90
R 100 N 30 5500 ± 25% -A84-X830 24
R 140 N 30 6200 ± 25% -A705-X830 4
R 200 N 30 5500 ± 30% -A711-X830 2
Type Mate-
rial
A
Lvalue
nH
(1mT,
10 kHz, 25°C)
A
L1min
nH
(320 mT,
N49: 200 mT,
10 kHz,
100 °C)
Power loss per core
(measurement
conditions)
Ordering
code
B64290-
PU
Pcs
Ring Cores
14 3.97 Siemens Matsushita Components
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 compo-
nents 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 inter-
national 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.
Ring Cores
