B66424C1013D001 Datasheet, PDF (3/4 Pages) EPCOS – Ferrite accessories

Ferrite accessories
Coil former EFD30
Preliminary data
Cautions and warnings
EFD30/13-1 PTH
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 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 2007, chapter “General – Definitions, 8.1”.
Effects of core combination on AL 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 2007, chapter “General – Definitions, 8.2”.
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.
Processing notes
– The start of the winding process should be soft. Else the flanges may be destroid.
– To strong winding forces may blast the flanges or squeeze the tube that the cores can no
more be mount.
– To long soldering time at high temperature (>300 °C) may effect coplanarity or pin
arrangement.
– Not following the processing notes for soldering of the J-leg terminals may cause solderability
problems at the transformer because of pollution with Sn oxyd of the tin bath or burned
insulation of the wire. For detailed information see Data Book 2007, chapter “Processing
notes, 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.
SMP IN FER D PD
Page 3 of 4
2007-02-01