NQ21HT449
Newbie level 6
![Newbie level 6](/styles/images/ranks/blevel3.gif)
Hello, I'm trying to simulate real inductors in my filter circuits using Coilcraft's library for LTSpice but I'm getting unacceptable losses. Here's an example:
First, I synthesize a Chebyshev BPF at 25 MHz and it shows an ideal curve.
I then perform a parametric search on Coilcraft's website and I select ceramic inductor with high Q and low ESR.
Then I replace ideal inductor with their frequency model inductor and I get -0.925 dB from just a single inductor. In this example, there's only one inductor, if I simulate higher order circuits, with multiple inductors, I get even more loss, which is not going to work for our application.
I'm trying to understand, firstly, whether my setup in LTSpice is correct and secondly, what is the source of the loss. It seems that DCR is the culprit.
If that's the case, is it possible to design a high order band pass filter working in low MHz range with real inductors or is there a fundamental limitation of low Q at those frequencies?
First, I synthesize a Chebyshev BPF at 25 MHz and it shows an ideal curve.
I then perform a parametric search on Coilcraft's website and I select ceramic inductor with high Q and low ESR.
Then I replace ideal inductor with their frequency model inductor and I get -0.925 dB from just a single inductor. In this example, there's only one inductor, if I simulate higher order circuits, with multiple inductors, I get even more loss, which is not going to work for our application.
I'm trying to understand, firstly, whether my setup in LTSpice is correct and secondly, what is the source of the loss. It seems that DCR is the culprit.
If that's the case, is it possible to design a high order band pass filter working in low MHz range with real inductors or is there a fundamental limitation of low Q at those frequencies?