SPICE

Document 267
SPICE Model – MSS1278T
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
VAR
C
R2
RVAR1
VAR
R1
LVAR
• 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)
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.
US +1-847-639-6400 [email protected]
UK +44-1236-730595 [email protected]
Taiwan +886-2-2264 3646 [email protected]
China +86-21-6218 8074 [email protected]
Singapore + 65-6484 8412 [email protected]
Document 267-1 Revised 07/19/12
© Coilcraft Inc. 2012
This product may not be used in medical of high
risk applications without prior Coilcraft approval.
Specification subject to change without notice.
Please check out web site for latest information.
Document 267
SPICE Model for Coilcraft MSS1278T Power Inductors
Frequency limit
LVAR Coefficients
of model (MHz)
Part number Lower Upper
R1 ()
R2 ()
C (pF)
k1­k2
k3
k4
k5
MSS1278T-1020.1 300 10
0.0063 3.7 8.00E-05 0.24 1.0 0.0085 9.30E-06
MSS1278T-1420.1 200
6.5 0.0088 3.5 1.20E-04 0.40 1.4 0.0280 9.85E-06
MSS1278T-2220.1 100
5.1 0.0094 6.1 2.75E-04 0.55 2.2 0.0260 9.10E-06
MSS1278T-2720.1 100
3.5 0.0101 9.5 1.30E-04 0.86 2.7 0.0750 9.90E-06
MSS1278T-392
0.1100 4.0 0.0117 8.03.15E-04 1.2 3.90.1609.85E-06
MSS1278T-472
0.1100 5.4 0.0139 3.24.25E-04 1.5 4.70.0739.60E-06
MSS1278T-562
0.1100 3.8 0.0157 5.03.00E-04 1.5 5.60.0899.70E-06
MSS1278T-6820.1 90
4.2 0.0191 8.4 9.25E-04 2.0 6.8 0.130 9.50E-06
MSS1278T-822
0.1100 5.0 0.0203 5.15.40E-04 2.2 8.20.2009.80E-06
MSS1278T-103
0.1100 7.2 0.0218 9.97.50E-04 3.710 0.2909.85E-06
MSS1278T-123
0.1100 6.0 0.0232 9.28.75E-04 3.912 0.3709.85E-06
MSS1278T-153
0.1806.20.0279
11.6
7.50E-044.8
150.370
9.88E-06
MSS1278T-183
0.1100 4.6 0.0308 11.04.00E-03 8.818 0.5009.70E-06
MSS1278T-223
0.1906.50.03558.2
8.00E-038.7
220.540
9.30E-06
MSS1278T-273
0.1704.20.0450
11.2
1.00E-038.6
270.470
9.92E-06
MSS1278T-3330.1 30 15
0.0619 14.3 2.00E-03 11 33
0.690 9.90E-06
MSS1278T-3930.1 40 12
0.0691 13.7 2.00E-03 13 39
0.840 9.94E-06
MSS1278T-473
0.140 9.0 0.072311.6
3.00E-03
1647 1.509.94E-06
MSS1278T-563
0.13012 0.080215.9
3.00E-03
1856 1.701.00E-05
MSS1278T-683
0.14010 0.091313.5
5.00E-03
2868 2.501.00E-05
MSS1278T-823
0.150 9.0 0.125914.8
4.00E-03
2882 2.201.01E-05
MSS1278T-104
0.18011 0.135113.1
5.50E-03
34100 3.001.01E-05
MSS1278T-124
0.17012 0.182313.0
5.00E-03
38
120 2.101.02E-05
MSS1278T-154
0.12012 0.216518.4
7.00E-03
60
150 5.901.02E-05
MSS1278T-184
0.13011 0.229012.7
1.00E-02
65180 4.001.03E-05
MSS1278T-224
0.11019 0.323618.7
8.00E-03
54220 4.901.06E-05
MSS1278T-274
0.11024 0.415619.4
7.00E-03
61270 4.701.11E-05
MSS1278T-334
0.16011 0.487314.6
1.00E-02
90330 5.101.11E-05
MSS1278T-394
0.13016 0.533616.9
1.20E-02
71390 7.201.12E-05
MSS1278T-474
0.11017 0.707515.2
1.30E-02
100470 5.901.22E-02
MSS1278T-564
0.11019 0.777415.4
1.40E-02
105
560 4.901.41E-05
MSS1278T-684
0.11018 1.045 15.3
1.10E-02
100
680 4.901.67E-05
MSS1278T-824
0.11028 1.166 19.2
1.40E-02
130
820 6.002.21E-05
MSS1278T-105
0.1 936 1.334 16.82.10E-02
150
100011.0 1.75E-05
US +1-847-639-6400 [email protected]
UK +44-1236-730595 [email protected]
Taiwan +886-2-2264 3646 [email protected]
China +86-21-6218 8074 [email protected]
Singapore + 65-6484 8412 [email protected]
Document 267-95 Revised 07/19/12
© Coilcraft Inc. 2012
This product may not be used in medical of high
risk applications without prior Coilcraft approval.
Specification subject to change without notice.
Please check out web site for latest information.