SPICE

Document 558
SPICE Model – 1008AF
This lumped-element (SPICE) model data simulates the
frequency-dependent behavior of Coilcraft RF 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
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.
Measurements were also taken on a network analyzer
over a brass ground plane with the component centered
over an air gap with a width of 0.060 inch (1.524 mm), as
illustrated in Figure 1. The test pads were 30 mil (50 Ohm)
wide traces of tinned gold over 25 mil thick alumina, and
were not included in the gap. The TRL* calibration plane
is also illustrated in Figure 1.
RVAR2
VAR
C
R2
R1
RVAR1
VAR
LVAR
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.
• f is the frequency in Hz
• RVAR2 is the resistance in Ohms
The value of the frequency-dependent inductance LVAR
is calculated from:
LVAR = k3 − k4 * LOG (k5 * f)
Pad
Air gap
Pad
Brass
ground
plane
• k3, k4, and k5 are shown in the accompanying table.
• f is the frequency in Hz
• LVAR is the inductance in µH
Calibration
plane
Figure 1. Test Setup
• LOG is the natural LOG (base e)
Disclaimer
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.
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.
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 558-1 Revised 08/03/11
Document 558
SPICE Model for Coilcraft 1008AF RF Inductors
Frequency limit
of model (MHz)
Part number Lower Upper
R1 ()
1008AF-112 0.1 400 800
1008AF-132 0.1 300 150
1008AF-152 0.1 150 125
1008AF-192 0.1 200 150
1008AF-222 0.1 150
70
1008AF-272 0.1 150
80
1008AF-332 0.1 100
80
1008AF-392 0.1 100
80
1008AF-472 0.1 80
80
1008AF-582 0.1 80
75
1008AF-682 0.1 60
50
1008AF-822
0.1 60
20
LVAR Coefficients
R2 ()
0.105
0.110
0.125
0.140
0.155
0.190
0.210
0.220
0.435
0.280
0.315
0.395
C (pF)
0.08
0.44
0.84
0.47
1.10
0.97
1.40
1.41
1.44
1.49
2.22
2.40
k1­k2
k3
k4
k5
4.50E-040.45 1.4152.50E-021.00E-07
7.00E-040.54 1.5642.90E-021.00E-07
6.60E-040.70 1.8642.90E-021.00E-07
8.00E-040.85 2.3023.20E-021.00E-07
2.00E-040.85 2.6363.50E-021.00E-07
4.00E-041.10 3.2614.50E-021.00E-07
9.00E-041.40 3.9495.20E-021.00E-07
5.00E-041.70 4.6826.30E-021.00E-07
3.00E-042.00 5.5797.10E-021.00E-07
7.00E-042.68 6.9129.00E-021.00E-07
5.00E-042.70 8.2731.20E-011.00E-07
5.00E-04 2.80 10.41 1.80E-011.00E-07
Document 558-5 Revised 08/02/11