Document 267
SPICE Model – XFL3012
This lumped-element (SPICE) model data simulates
the frequency-dependent behavior of Coilcraft power
inductors within the frequency range shown in the accompanying table for each individual inductor.
The data represents de-embedded measurements, as
described below. Effects due to different customer circuit
board traces, board materials, ground planes or interactions 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.
Lumped Element Modeling Method
The value of the frequency-dependent variable resistor
RVAR1 is calculated from:
RVAR1 = k1 *
• k1 is shown for each value in the accompanying table.
• f is the frequency in Hz
• RVAR1 is the resistance in Ohms
The value of the frequency-dependent variable resistor
RVAR2 is calculated from:
RVAR2 = k2 *
• k2 is shown for each value in the accompanying table.
Measurements were made using a 50 Ohm impedance
analyzer. Fixture compensation was performed to remove
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.
• f is the frequency in Hz
The equivalent lumped element model schematic is shown
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 elements are determined by the overall performance of the
lumped element model compared to the measurements
taken of the component.
• k3, k4, and k5 are shown in the accompanying table.
• 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)
• f is the frequency in Hz
• LVAR is the inductance in µH
• LOG is the natural LOG (base e)
Coilcraft makes every attempt to provide accurate measurement data and software, representative of our components, in a usable format. Coilcraft, however, disclaims
all warrants relating to the use of its data and software,
whether expressed or implied, including without limitation 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.
Document 267-1 Revised 07/28/11
Document 267
SPICE Model for Coilcraft XFL3012 Power Inductors
Frequency limit
of model (MHz)
Part number Lower Upper
R1 ()
XFL3012-221 0.1 400 75
XFL3012-361 0.1 300 45
XFL3012-601 0.1 300 35
XFL3012-1020.1200 40
XFL3012-1520.1200 30
XFL3012-2220.1100 30
XFL3012-3320.1100 30
XFL3012-4720.1100 35
LVAR Coefficients
R2 ()
C (pF)
0.014 1.08 1.00E-040.0330.22
0.019 1.44 6.00E-050.0610.36
0.023 1.63 4.00E-050.0960.6
0.0352.05 7.00E-05
0.0602.20 6.00E-05
0.0812.16 6.00E-05
0.1062.18 2.00E-05
0.1432.24 2.00E-05
0.001 3.00E-06
0.001 3.00E-06
0.001 5.00E-06
Document 267-73 Revised 07/29/11