Document 267
SPICE Model – XFL4020
This lumped-element (SPICE) model data simulates
The value of the frequency-dependent variable resistor
RVAR1 is calculated from:
the frequency-dependent behavior of Coilcraft power
inductors within the frequency range shown in the ac-
companying table for each individual inductor.
RVAR1 = k1
*
•ꢀ k1ꢀisꢀshownꢀforꢀeachꢀvalueꢀinꢀtheꢀaccompanyingꢀtable.
The data represents de-embedded measurements, as
described below.Effects due to different customer circuit
board traces, board materials, ground planes or interac-
tions with other components are not included and can
have a significant effect when comparing the simulation
to measurements of the inductors using other production
verification instruments and fixtures.
•ꢀ fꢀisꢀtheꢀfrequencyꢀinꢀHz
•ꢀ RVAR1 is the resistance in Ohms
The value of the frequency-dependent variable resistor
RVAR2 is calculated from:
RVAR2 = k2
*
•ꢀ k2ꢀisꢀshownꢀforꢀeachꢀvalueꢀinꢀtheꢀaccompanyingꢀtable.ꢀ
Lumped Element Modeling Method
•ꢀ fꢀisꢀtheꢀfrequencyꢀinꢀHz
Measurements were made using a 50 Ohm impedance
analyzer.Fixturecompensationwasperformedtoremove
fixture effects. No DC bias current was applied in any of
the measurements. The lumped element values were
determined by optimizing the simulation model to an
average of the measurements. This method results in a
model that represents as closely as possible the typical
frequency-dependent behavior of the component within
the model frequency range.
•ꢀ RVAR2 is the resistance in Ohms
Note: The log function in the following equation is the
natural logarithm, base e, not base 10.
The value of the frequency-dependent inductance LVAR
is calculated from:
LVAR = k3 − k4 * LOG (k5 f)
*
•ꢀ k3,ꢀk4,ꢀandꢀk5ꢀareꢀshownꢀinꢀtheꢀaccompanyingꢀtable.
•ꢀ fꢀisꢀtheꢀfrequencyꢀinꢀHz
Theequivalentlumpedelementmodelschematicisshown
below. Each model should only be analyzed at the input
and output ports. Individual elements of the model are
not determined by parameter measurement. The ele-
ments are determined by the overall performance of the
lumped element model compared to the measurements
taken of the component.
•ꢀ LVARꢀisꢀtheꢀinductanceꢀinꢀµH
•ꢀ LOGꢀisꢀtheꢀnaturalꢀLOGꢀ(baseꢀe)
Disclaimer
Coilcraft makes every attempt to provide accurate mea-
surement data and software, representative of our com-
ponents, in a usable format.Coilcraft, however, disclaims
all warrants relating to the use of its data and software,
whether expressed or implied, including without limita-
tion any implied warranties of merchantability or fitness
for a particular purpose. Coilcraft cannot and will not be
liable for any special, incidental, consequential, indirect
or similar damages occurring with the use of the data
and/or software.
R
VAR2
C
R1
L
R2
R
VAR1
VAR
Document 267-1 Revised 07/28/11