SPICE

Document 158
SPICE Model – 1008CS
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 1008CS Chip Inductors
R1
⏲)
Part number (⏲
1008CS-100
1008CS-120
1008CS-150
1008CS-180
1008CS-220
1008CS-270
1008CS-330
1008CS-390
1008CS-470
1008CS-560
1008CS-680
1008CS-820
1008CS-101
1008CS-121
1008CS-151
1008CS-181
1008CS-221
1008CS-271
1008CS-331
1008CS-391
8
7
7
7
8
8
9
9
9
7
6
12
13
13
14
18
18
19
20
27
R2
⏲)
(⏲
C (pF)
L (nH)
0.10
0.10
0.10
0.10
0.10
0.10
0.10
0.20
0.20
0.20
0.20
0.20
0.60
0.60
0.70
0.80
0.80
0.90
1.10
1.10
0.065
0.100
0.153
0.083
0.124
0.185
0.117
0.149
0.118
0.160
0.137
0.179
0.135
0.136
0.136
0.130
0.147
0.144
0.132
0.138
9.8
12.0
15.0
18.0
22.0
27.0
33.0
39.0
47.0
56.0
68.0
81.0
100
120
150
180
224
265
330
380
k
1.96E-05
2.40E-05
3.12E-05
3.16E-05
3.69E-05
4.41E-05
5.18E-05
5.50E-05
6.40E-05
7.40E-05
9.20E-05
1.15E-04
1.25E-04
1.51E-04
1.10E-04
1.40E-04
1.90E-04
2.32E-04
2.84E-04
3.49E-04
Upper
limit
(MHz)
6700
4900
3700
4600
3400
2500
2900
2300
2400
1900
1900
1500
1600
1400
1300
1200
1000
900
900
800
R1
⏲)
Part number (⏲
1008CS-471
1008CS-561
1008CS-621
1008CS-681
1008CS-751
1008CS-821
1008CS-911
1008CS-102
1008CS-122
1008CS-152
1008CS-182
1008CS-222
1008CS-272
1008CS-332
1008CS-392
1008CS-472
1008CS-562
1008CS-682
1008CS-822
31
36
37
37
44
41
53
90
73
83
85
84
112
134
121
163
64
148
134
R2
⏲)
(⏲
C (pF)
1.20
1.30
1.40
1.50
1.50
1.60
1.70
1.80
2.00
2.30
2.60
2.80
3.20
3.40
3.60
4.00
4.00
4.90
6.00
0.156
0.172
0.143
0.139
0.138
0.135
0.155
0.209
0.201
0.249
0.278
0.258
0.398
0.285
0.401
0.381
5.304
1.357
2.911
Specifications subject to change without notice.
© Coilcraft, Inc. 2009
L (nH)
465
550
615
665
740
810
895
975
1215
1515
1825
2200
2700
3300
3900
4600
5250
6800
8200
k
4.27E-04
5.18E-04
5.74E-04
6.10E-04
6.90E-04
8.10E-04
7.80E-04
8.20E-04
1.05E-03
1.71E-03
2.04E-03
2.46E-03
2.55E-03
3.27E-03
4.23E-03
5.00E-03
3.04E-03
3.54E-03
4.38E-03
Upper
limit
(MHz)
700
600
600
600
600
600
500
400
400
300
300
300
200
200
200
200
100
100
100
Document 158-10 Revised 11/13/02