ADS Sparam mini-circuit balun 4-port but s3p?

ADS Sparam mini-circuits balun 4-port but s3p?

Hello all,

I'm used to working with ADS a little bit, but I can't seem to understand to simulate the TCM4-452X+ wideband balun from mini-circuits.

I downloaded the s3p-file from over here:
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Datasheet is here:
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First I don't really get why I got a S3P-file while the component has 4 ports? Primary dot, primary, secondary dot and secondary.
Second I don't understand how I should interprete this file? What is corresponding to port 1, 2 and 3? It is not documented as far as I know.

When I try to simulate to find out which port is what I never even get the graphs for return loss (S11) close to the datasheet even switching the excitation port around.

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What am I missing here?
Thanks alot!

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Apparently I was dumb enough to wrongly interpret the Ohm's ratio of the 1:4 transformer. Instead of having 12.5 Ohms at the secondary it should have been 200 Ohms, hence the mismatch in S11. Now I get figures like this (which are close to the datasheet)

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However, my question still remains as I want to use this component for a downconversion in impedance (50 to 12.5 Ohms). Thus I have single-ended 50 Ohm in at the secondary and I want 12.5 Ohm at the primary, differential. But that is not the way the s3p is measured. How should I handle this?

Re: ADS Sparam mini-circuits balun 4-port but s3p?

The component does not 4 ports.It's got only 3 ports ( Primary, Secondary and Secondary_Dot)
Primary_Dot is a reference ( GND ) for Single Ended Input.So, there isn't any discrepancy..

Re: ADS Sparam mini-circuits balun 4-port but s3p?

Thank you for your reply, however I don't want to use it this way.
I would like to do a 50Ohm to 12.5Ohm conversion, so is it also possible to add a ground at the secondary and have the differential output on the primary?

Re: ADS Sparam mini-circuits balun 4-port but s3p?

The_Dutchman said:

I would like to do a 50Ohm to 12.5Ohm conversion, so is it also possible to add a ground at the secondary and have the differential output on the primary?

Click to expand...

Due to the transformer design, the high impedance (4:1) is always in the symmetric side (center tap).

So you can do differential 50 Ohm (25 + 25) to single ended 12.5 Ohm.

Re: ADS Sparam mini-circuits balun 4-port but s3p?

Is it possible to elaborate on that? Maybe a reference or a paper so I can understand it?
Any idea how can I get a wideband 12Ohm (balanced) to 50 Ohm (unbalanced) transformation?

Re: ADS Sparam mini-circuits balun 4-port but s3p?

The "Guanella" 1:4 transmission line transformer can be used in different configurations, e.g. unbal-unbal. bal-unbal makes less sense according to the impedance values, but should work, too. The s3p files are however only specifying the unbal-bal configuration, as shown in the datasheet "Electrical Schematic". Additional parameters become effective when using the part in different configurations, so you have to do your own measurements. I would also expect a reduced higher cut-off frequency at 1/4 of the designed impedance.