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Important!
Even the most current version of ADS may not contain up-to-date libraries of our inductor models and
S-parameters. Coilcraft provides the most current and accurate versions of
our models on our web site.
S-Parameters
While
S-parameters are convenient to use, the frequency resolution may not be
adequate for narrowband simulations and yield analysis is not possible.
If the frequency resolution is inadequate or if you wish to perform a
yield analysis, use our lumped element (SPICE)
models.
Our
S-parameters are provided in a single compressed “zipped” file. The file
must be “unzipped” after downloading to obtain the separate inductor
value S-parameter files.
After
the files are unzipped, run ADS.
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Select the S2P icon from the Data Items
menu.
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Place the generic two-port element onto
the design.
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Double click the icon and select the S-parameter file by browsing to
the directory where it was saved.
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Add a ground to the ground port and
connect the S-parameters to the rest of the circuit.
To
model our inductors, each individual lumped element for the complete
model must be placed into the schematic. Refer to the published SPICE
document for the inductor you are modeling.
RF
inductor models require R2, Rvar1, L, C and R1
Power
inductor models require R2, Rvar1, Lvar, C, R1 and Rvar2
For
these elements to be placed properly into ADS, there cannot be any
frequency dependent passive elements. These are replaced with an equation
based Z1 port element. An example is provided how to implement the
Rvar1 for a rf chip inductor:
| Rvar1= k1 * sqrt(freq) |
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The
following example shows how to implement Rvar1, Lvar, and Rvar2.
To
implement Lvar, use the following equation:
(2 *
pi *
freq * (k3 – k4 * log(k5 * freq) * 10^-6) * j
where:
10^-6 represents µH.
Since
the Lvar is only the imaginary impedance, it can be combined with Rvar1
to minimize the number of components:
Z[1,1]
= Rvar1 + Lvar * j
IMPORTANT: Be sure to verify the
units of the inductor. In Lvar:
mH is 10^-3
µH is 10^-6
nH is 10^-9
To
place the Z1P file in the schematic:
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Select the Z1P file from the equation based item menu.
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Place the element on the schematic.
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Double click the element and assign the equation to the element.
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Replace k1 with the value from the inductor published model table.
For
frequency dependent inductance (Lvar2):
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Select the Z1P file from the equation based item menu.
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Place the element on the schematic.
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Double click the element and assign the equation to the element.
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Replace k1, k3, k4, k5 with values from the published model table.
Connect the input and output of the model into the circuit and the model
is complete. |