SPICE

Document 158
SPICE Model – 1206CS
This lumped-element (SPICE) model data simulates the
frequency-dependent behavior of Coilcraft RF surface
mount inductors from 1 MHz to the upper frequency limit
shown in the accompanying table.
The equivalent lumped element model schematic is
shown below. The element values R1, R2, C, and L are
listed for each component value. The value of the frequency-dependent variable resistor RVAR relates to the
skin effect and is calculated from:
RVAR = k *
•
•
k is shown for each value in the accompanying table.
f is the frequency in Hz
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 typical production verification instruments and fixtures.
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.
Typically, the Self-Resonant Frequency (SRF) of the
component model will be higher than the measurement of
the component mounted on a circuit board. The parasitic
reactive elements of a circuit board or fixture will effectively
lower the circuit resonant frequency, especially for very
small inductance values. Since data sheet specifications
are based on typical production measurements, and the
SPICE models are based on de-embedded measurements as described below, the model results may be
different from the data sheet specifications.
Lumped Element Modeling Method
The measurements were made over a brass ground
plane with each component centered over an air gap, as
illustrated in Figure 1. The gap width for each size
component is given in Table 1. The test pads were 30 mil
Table 1. Test Gap
Size
0302
0402,0403
0603
0805
1008
1206
1812
Gap Width (inch / mm)
0.017 / 0.432
0.017 / 0.432
0.026 / 0.660
0.040 / 1.016
0.060 / 1.524
0.080 / 2.032
0.120 / 3.048
(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.
Pad
Pad
Brass
ground
plane
Calibration
plane
Figure 1. Test Setup
The lumped element values were determined by matching
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 up to a frequency just above the
self-resonant frequency of the model.
The lumped element models were used to generate our
2-port S-parameters and therefore give identical results. The S-parameters are available on our web site
at http://www.coilcraft.com/models.cfm.
Disclaimer
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.
Specifications subject to change without notice.
© Coilcraft, Inc. 2009
Air gap
Document 158-1 Revised 03/16/09
Document 158
SPICE Model for Coilcraft 1206CS Chip Inductors
R1
⏲)
Part number (⏲
1206CS-030
1206CS-060
1206CS-100
1206CS-120
1206CS-150
1206CS-180
1206CS-220
1206CS-270
1206CS-330
1206CS-390
1206CS-470
1206CS-560
1206CS-680
1206CS-820
1206CS-101
1206CS-121
12
11
11
11
8
12
14
14
10
12
14
13
10
12
10
18
R2
⏲)
(⏲
0.1
0.1
0.1
0.1
0.1
0.1
0.1
0.1
0.1
0.1
0.1
0.1
0.2
0.2
0.2
0.2
C (pF)
L (nH)
0.051
0.035
0.043
0.086
0.050
0.078
0.101
0.082
0.131
0.086
0.115
0.107
0.127
0.089
0.091
0.052
3.4
6.8
11.5
15
18
21
24
29
35
39
47
56
68
83
100
118
k
4.35E-06
1.37E-05
1.95E-05
2.58E-05
3.02E-05
3.22E-05
3.97E-05
4.67E-05
4.95E-05
6.21E-05
7.31E-05
9.00E-05
1.03E-04
1.30E-04
1.57E-04
1.73E-04
Upper
limit
(MHz)
12800
10900
7900
4900
5900
4400
3600
3600
2600
3100
2400
2300
1900
2100
1900
2150
R1
⏲)
Part number (⏲
1206CS-151
20
1206CS-181
15
1206CS-221
25
1206CS-271
25
1206CS-331
33
1206CS-391
35
1206CS-471
35
1206CS-561
25
1206CS-621
28
1206CS-681
28
1206CS-751
5
1206CS-821
5
1206CS-911
5
1206CS-102 125
1206CS-122 100
R2
⏲)
(⏲
0.3
0.4
0.5
0.5
0.6
0.7
1.3
1.3
1.5
1.5
2.2
1.8
2.8
2.8
3.2
Specifications subject to change without notice.
© Coilcraft, Inc. 2009
C (pF)
L (nH)
0.089
140
0.067
183
0.082
223
0.074
280
0.071
329
0.058
390
0.075
470
0.067
557
0.071
615
0.059
670
0.062
720
0.060
775
0.063
810
0.059
835
0.060 1060
k
1.91E-04
2.67E-04
3.15E-04
3.95E-04
4.01E-04
4.85E-04
6.02E-04
6.70E-04
6.71E-04
7.51E-04
8.40E-04
9.70E-04
1.01E-03
9.90E-04
1.33E-03
Upper
limit
(MHz)
1600
1600
1300
1300
1200
1100
1000
900
800
850
760
760
730
730
650
Document 158-16 Revised 11/13/02