Ferrites and accessories
EFD 25/13/9
Core and accessories
Series/Type:
Date:
B66421, B66422
May 2017
EPCOS AG 2017. Reproduction, publication and dissemination of this publication, enclosures hereto and the
information contained therein without EPCOS’ prior express consent is prohibited.
EPCOS AG is a TDK Group Company.
EFD 25/13/9
Core
■
E core with flattened, lower center leg
B66421
for especially flat transformer design
■
For DC/DC converters
■
Delivery mode: single units
Magnetic characteristics
(per set)
Σl/A
l
e
A
e
A
min
V
e
= 0.98 mm
–1
= 57 mm
= 58 mm
2
= 57 mm
2
= 3310 mm
3
Approx. weight
16.6 g/set
Ungapped
Material
N87
N97
A
L
value
nH
2000 +30/–20%
2100 +30/–20%
μ
e
1560
1640
P
V
W/set
< 1.8 (200 mT, 100 kHz, 100 °C)
< 1.5 (200 mT, 100 kHz, 100 °C)
Ordering code
B66421G0000X187
B66421G0000X197
Other A
L
values/air gaps and materials available on request – see Processing remarks on page 4.
Gapped
(A
L
values/air gaps examples)
Material
N87
A
L
value
nH
160
±10%
250
±10%
315
±10%
160
±10%
μ
e
125
195
246
125
g
approx. mm
0.55
0.30
0.22
0.50
Ordering code
B66421U0160K187
B66421U0250K187
B66421U0315K187
B66421U0160K197
N97
The A
L
value in the table applies to a core set comprising one ungapped core (dimension g = 0 mm)
and one gapped core (dimension g > 0 mm).
Calculation factors
(for formulas, see
“E cores: general information”
)
Material
Relationship between
air gap – A
L
value
K1 (25 °C)
N87
Validity range:
103
K2 (25 °C)
–0.734
Calculation of saturation current
K3 (25 °C)
154
K4 (25 °C)
–0.796
K3 (100 °C) K4 (100 °C)
138
–0.873
K1, K2: 0.10 mm < s < 1.40 mm
K3, K4: 50 nH < A
L
< 410 nH
Please read
Cautions and warnings
and
Important notes
at the end of this document.
2
5/17
EFD 25/13/9
Accessories
Coil former
GFR thermosetting plastic (UL 94 V-0, insulation class to IEC 60085:
F max.operating temperature 155 °C), color code black
Sumikon PM 9630
®
[
E41429 (M)
]
, SUMITOMO BAKELITE CO LTD
Solderability: to IEC 60068-2-20, test Ta, method 1 (aging 3): 235 °C, 2 s
Resistance to soldering heat: to IEC 60068-2-20, test Tb, method 1B: 350 °C, 3.5 s
Winding:
see Processing notes, 2.1
Pins:
Squared pins
Yoke
Material:
Coil former
Sections
1
A
N
mm
2
40.7
l
N
mm
50
A
R
value
μΩ
42.3
Pins
10
B66422W1010D001
B66422B2000X000
Stainless spring steel (0.4 mm)
Ordering code
Material:
B66422
Yoke (ordering code per piece, 2 are required)
Coil former
Yoke
View A
Please read
Cautions and warnings
and
Important notes
at the end of this document.
3
5/17
Ferrites and accessories
Cautions and warnings
Cautions and warnings
Mechanical stress and mounting
Ferrite cores have to meet mechanical requirements during assembling and for a growing number
of applications. Since ferrites are ceramic materials one has to be aware of the special behavior
under mechanical load.
As valid for any ceramic material, ferrite cores are brittle and sensitive to any shock, fast tempera-
ture changing or tensile load. Especially high cooling rates under ultrasonic cleaning and high static
or cyclic loads can cause cracks or failure of the ferrite cores.
For detailed information see data book, chapter
“General - Definitions, 8.1”.
Effects of core combination on A
L
value
Stresses in the core affect not only the mechanical but also the magnetic properties. It is apparent
that the initial permeability is dependent on the stress state of the core. The higher the stresses are
in the core, the lower is the value for the initial permeability. Thus the embedding medium should
have the greatest possible elasticity.
For detailed information see data book, chapter
“General - Definitions, 8.1”.
Heating up
Ferrites can run hot during operation at higher flux densities and higher frequencies.
NiZn-materials
The magnetic properties of NiZn-materials can change irreversible in high magnetic fields.
Ferrite Accessories
EPCOS ferrite accessories have been designed and evaluated only in combination with EPCOS
ferrite cores. EPCOS explicitly points out that EPCOS ferrite accessories or EPCOS ferrite cores
may not be compatible with those of other manufacturers. Any such combination requires prior te-
sting by the customer and will be at the customer‘s own risk.
EPCOS assumes no warranty or reliability for the combination of EPCOS ferrite accessories with
cores and other accessories from any other manufacturer.
Processing remarks
The start of the winding process should be soft. Else the flanges may be destroyed.
– Too strong winding forces may blast the flanges or squeeze the tube that the cores can not be
mounted any more.
– Too long soldering time at high temperature (>300 °C) may effect coplanarity or pin arrange-
ment.
– Not following the processing notes for soldering of the J-leg terminals may cause solderability
problems at the transformer because of pollution with Sn oxyde of the tin bath or burned insula-
tion of the wire. For detailed information see chapter
“Processing notes”,
section 2.2.
– The dimensions of the hole arrangement have fixed values and should be understood as
a recommendation for drilling the printed circuit board. For dimensioning the pins, the group
of holes can only be seen under certain conditions, as they fit into the given hole arrangement.
To avoid problems when mounting the transformer, the manufacturing tolerances for positioning
the customers’ drilling process must be considered by increasing the hole diameter.
Please read
Cautions and warnings
and
Important notes
at the end of this document.
4
5/17
Ferrites and accessories
Cautions and warnings
Display of ordering codes for EPCOS products
The ordering code for one and the same product can be represented differently in data sheets,
data books, other publications and the website of EPCOS, or in order-related documents such as
shipping notes, order confirmations and product labels.
The varying representations of the
ordering codes are due to different processes employed and do not affect the
specifications of the respective products.
Detailed information can be found on the Internet
under www.epcos.com/orderingcodes.
Please read
Cautions and warnings
and
Important notes
at the end of this document.
5
5/17
京公网安备 11010802033920号
EEWORLD
