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[SOLVED] 2.3 GHz lna design parameter vs netlist

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jesuschrist

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2.3 GHz lna design sparameter vs netlist

Hi. I am trying to design an LNA at 2.3 ghz with infineon's BFP 740 ultra low noise transistors.
On their page there is an axamle at the same frequency. When i use sparamets i get 0.18 db NF
but when i use netlist with the same matching circuit I get nothing so i changed the bias and now I am getting 0.7 db NF at best. So which one is wiser to use netlist or sparameters ?
 

Re: 2.3 GHz lna design sparameter vs netlist

Describe your situations correctly.

jesuschrist said:
When i use sparamets i get 0.18 db NF
but when i use netlist with the same matching circuit I get nothing so i changed the bias and now I am getting 0.7 db NF at best So which one is wiser to use netlist or sparameters ?
Click to expand...
What do you mean by netlist ?

Do you mean netlist is a S-parameter simulation based on Gummel-Poon-Model ?

Is NF=0.18dB NFmin ?
On the hand, NF=0.7dB is not.

Describe your situations correctly.

**broken link removed**
 
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Re: 2.3 GHz lna design sparameter vs netlist

The situation is this. In infineon website for bfp 740 https://www.infineon.com/cms/en/pro...ype=db3a3044243b532e012501620a877ce0#ispnTab7
you can download SimModel with symbol and footprint AWR MWO v1.0.zip file. Inside that file there is an example at 2.3 GHz. The example uses both S parameters and Netlist(mdl file) of bfp740. When you look at the design with Sparameter data set, It shows 0.1639 db NF. They have the same simulation with mdl file of bfp740 but,Unfortunately their design with mdl file of transistor is not correctly simulated. But when i used the same configuration they have on the example I get around 0.68 dB noise. at 2.3 Ghz which is close to their datasheets. SO i tought their Sparameter files might be wrong since datasheet shows 0.55 dB noise at 1.8 GHz at best.
 

Re: 2.3 GHz lna design sparameter vs netlist

jesuschrist said:
you can download SimModel with symbol and footprint AWR MWO v1.0.zip file.
Click to expand...
I don't have AWR MWO.
However I can see contents of "BFP740H6327XTSA1/Simulation Data".

Which one do you use in your simulation
(1) BFP740.net (SPICE Netlist using Gummel-Poon-Model)
(2) bfp740_spar.mdf (Small Signal Table Model written as Keysight EEsof MDIF Format)

We don't call (2) "Netlist".

I think you can not understand simulation model, NF and NFmin at all.

What file do you mean by "S-Parameter" ?
 
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Re: 2.3 GHz lna design sparameter vs netlist

jesuschrist said:
The situation is this. In infineon website for bfp 740 https://www.infineon.com/cms/en/pro...ype=db3a3044243b532e012501620a877ce0#ispnTab7
you can download SimModel with symbol and footprint AWR MWO v1.0.zip file. Inside that file there is an example at 2.3 GHz. The example uses both S parameters and Netlist(mdl file) of bfp740. When you look at the design with Sparameter data set, It shows 0.1639 db NF. They have the same simulation with mdl file of bfp740 but,Unfortunately their design with mdl file of transistor is not correctly simulated. But when i used the same configuration they have on the example I get around 0.68 dB noise. at 2.3 Ghz which is close to their datasheets. SO i tought their Sparameter files might be wrong since datasheet shows 0.55 dB noise at 1.8 GHz at best.
Click to expand...
I couldn't see 0.1639 dB NF in s-parameters data-set but anyway..
NF is NFmin what you see in the s-parameters data-set so that the transistor is matched (input) to Zopt to get the NFmin.You should do the same thing ( Zopt should have been supplied) to obtain the similar result.
 
Re: 2.3 GHz lna design sparameter vs netlist

This one is the simulation based on mdf format by using bfp740_spar.mdf done by infineon https://imgur.com/HFrMxef. This one is the one that I did by using BFP740.net (SPICE Netlist using Gummel-Poon-Model) https://imgur.com/vLuJM2T . Both are NF not NFmin.

HFrMxef.png

vLuJM2T.png
 
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Re: 2.3 GHz lna design sparameter vs netlist

jesuschrist said:
This one is the simulation based on mdf format by using bfp740_spar.mdf done by infineon https://imgur.com/HFrMxef. This one is the one that I did by using BFP740.net (SPICE Netlist using Gummel-Poon-Model) https://imgur.com/vLuJM2T . Both are NF not NFmin.

View attachment 135993

View attachment 135994
Click to expand...

That's exactly what I'm saying.The simulator takes NFmin value while it is simulating the transistor ( because it's been supplied in s-parameters data-set).But when you do this simulation with GP model even the bias conditions are exactly same, the NF will not be NFmin, instead NF will be "50 terminated Noise Figure".That's the difference.
 

Re: 2.3 GHz lna design sparameter vs netlist

BigBoss said:
The simulator takes NFmin value while it is simulating the transistor ( because it's been supplied in s-parameters data-set).
Click to expand...
I don't think so.

Even in simulation using (2) "bfp740_spar.mdf", I think impedance of ports are 50ohm.

jesuschrist said:
Both are NF not NFmin.
Click to expand...
 
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Re: 2.3 GHz lna design sparameter vs netlist

Noise Fİgure Comparison.png Here is the Noise Figure simulations of all 3 circuits. I have s parameter simulation, GP model simulation with same circuit as S parameter(Just a DC voltage source of 3.3V added for Bias didn't add anything to it, had the bias network in Spar circuit.) And lastly my own derivation of the same circuit with rogers 5880 and 2V DC source for lower Collector current and better Noise figure.
 
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Re: 2.3 GHz lna design sparameter vs netlist

jesuschrist said:
I have s parameter simulation, GP model simulation with same circuit as S parameter(Just a DC voltage source of 3.3V added for Bias didn't add anything to it, had the bias network in Spar circuit.)
Click to expand...
Simulation using (2) does not require bias at all.
However simlation using (1) require bias.
How do you feed bias for base and collector in Simulation using Gummel-Poon-Model ?

What values do you set Vce and Ic ?

I suspect you don't match same bias points between (1) and (2).

And Title of this thread should be changed to "2.3 GHz lna design, Small-Signal-Model v.s. Large-Signal-Model".

https://www.designers-guide.org/Forum/YaBB.pl?num=1212376329
 
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Re: 2.3 GHz lna design sparameter vs netlist

GP_model.pngmy_lna_bias.pngspar_model.png as you can see Spar model and GP model has the same bias which is Vc=1V Ic=3mA. But results are different from each other.
 

Re: 2.3 GHz lna design sparameter vs netlist

pancho_hideboo said:
I don't think so.
Click to expand...

So, how does a s-parameter simulation uses NF information ?? Is there any additional Noise Figure data in s-parameters data-set ? No.
It computes NF by using existing measured NF data in order to extract the actual NF data, right ?
If we know NFmin,Rn,Ys we can find F ( Microwave and RF Engineering-Roberto Sorrentino,Giovanni Bianchi.Page 429,Eq-11.32)
 

Re: 2.3 GHz lna design sparameter vs netlist

BigBoss said:
It computes NF by using existing measured NF data in order to extract the actual NF data, right ?
Click to expand...
Right.

BigBoss said:
If we know NFmin,Rn,Ys we can find F
Click to expand...
You can not understand noise parameters in S-parameter and NF calculation by using them at all.

NF is calculated by {s11, s12, s21, s22} and {NFmin, Rn, Gamma_opt}.
Maybe your Ys is equivalent to Gamma_opt.

So if Zsource is not Zopt, NF is not NFmin.

Touchstone format is a subset of MDIF.
{s11, s12, s21, s22} and {NFmin, Rn, Gamma_opt} are listed in MDIF file.
**broken link removed**

jesuschrist said:
as you can see Spar model and GP model has the same bias which is Vc=1V Ic=3mA.
Click to expand...
I don't think they are same.

Former is (Vce, Ic)=(1.0V, 3.0mA)
Latter is (Vce, Ic)=(1.05V, 3.79mA)

Current discrepancy is fairly large.

Compare NF with adjusting latter (Vce, Ic) as (1.0V, 3.0mA).

However I believe Small-Signal-Model not Large-Signal-Model since former is a raw data without approximation due to fitting.
 
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Re: 2.3 GHz lna design sparameter vs netlist

pancho_hideboo said:
Right.

You can not understand noise parameters in S-parameter and NF calculation by using them at all.
Click to expand...
Yeah.. Only you understand ALL, we know nothing..
pancho_hideboo said:
NF is calculated by {s11, s12, s21, s22} and {NFmin, Rn, Gamma_opt}.
Maybe your Ys is equivalent to Gamma_opt.

So if Zsource is not Zopt, NF is not NFmin.

Touchstone format is a subset of MDIF.
{s11, s12, s21, s22} and {NFmin, Rn, Gamma_opt} are listed in MDIF file.
**broken link removed**
Click to expand...
Can you show us Highness where the s-parameters are here ??

NF.PNG
 

Re: 2.3 GHz lna design sparameter vs netlist

BigBoss said:
Yeah.. Only you understand ALL, we know nothing..
Click to expand...
You often append wrong things elsewhere.

BigBoss said:
Can you show us Highness where the s-parameters are here ??
Click to expand...
Sorry, {s11,..,s22} are not used.

{s11,..,s22} are used in NF calculation, if s-parameters are cascaded like two stage amplifier.

BigBoss said:
NF is NFmin what you see in the s-parameters data-set so that the transistor is matched (input) to Zopt to get the NFmin.
Click to expand...
However, if Zsource is not Zopt, NF is not NFmin.
So all NF in this thread are not NFmin.
 
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Re: 2.3 GHz lna design sparameter vs netlist

This message board surely wishes to attract and keep our expert daily regular posters, and that is the aim of forum rules:

Remain respectful of other users, moderators and administrators at all times
All posts should be professional and courteous. You have every right to disagree with your fellow community members and explain your perspective, however, you are not free to attack, degrade, insult, or otherwise belittle them or the quality of this community.
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