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In this section, we discuss how to Resolve Differences in Ideal & Library Component Results and basic circuits of vendor library components.

In the previous section, we used the components provided by muRata for simulation and found that there were some differences between the simulation results and the results obtained with ideal components. Since the parameter values ​​of the components in the actual process are fixed and the choices are very limited, they cannot be modified arbitrarily. Therefore, when we use ideal components for very extreme designs, many of our efforts may become useless. Therefore, we need to understand how to use ideal components while getting closer to the actual situation.

We first open the last simulation result (TestBench_MyFilter.dds), and then select “History – Off”. At this time, only the most recent simulation result remains.

Then select “History – On” to use the current simulation results as a reference:

There will be differences between ideal components and actual components. One of the reasons is that we have not yet considered the loss factor (i.e., Q factor), so the simulation results we get are all ideal.

For the following experiments, we will create another copy of Design1 and name it “Design1_withQ”.

We open the copied schematic and select “Lumped-Components” in the Library Palettes on the left. In it, we can see (capacitors with Q factor) and (inductors with Q factor).

Now, we need to replace the previous ideal components with CAPQ and INDQ. There are many ways to do this:

• Directly add manually, modify one by one, delete the original components and place the new components in the corresponding position. This method is convenient to use when the number of components is small, but it is too troublesome when the number of components is large.
• Remember the keywords of the components (such as CAPQ, INDQ, L, etc.), and then directly modify the keywords of the components to replace them.
• We can also perform batch modification. First select all components that need to be replaced, then select “Edit – Component – ​​Swap Components”, and then modify the Cell name to replace all selected components at the same time.

Set the Q factor of INDQ to 15 and the Q factor of CAPQ to 100 (in specific design, we can obtain accurate data of Q factor by looking up the table).

After the modification is completed, we need to add the modified Symbol in TestBench and then disable Design1_Murata:

After saving the design, we perform simulation and obtain the following results:

It can be seen that the simulation results at this time are very close to the simulation results obtained using the components in the supplier library.

As for how to obtain accurate Q values ​​by looking up the table, in addition to downloading the supplier’s technical manual, we can also perform simulation under the included premise and then select “Insert – Template” in the simulation window:

In Em_Product, there is a template S_2port_Spiral for displaying the characteristics of a two-port spiral inductor.

Then click “OK” and we can see many predicted inductance values ​​and other parameters, which can be used to better design.

Next article: Polymorphism / Dynamic Model Selection (12)