Author Topic: AWR SPICE Models  (Read 7782 times)

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Offline tec5cTopic starter

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AWR SPICE Models
« on: May 30, 2016, 12:05:48 pm »
Another AWR question here.

I need to model a few components to use in AWR - MA46H201 varactor diode (1056 package), and NE3511S02 HJ-FET.

I have managed to get the SPICE model for the varactor diode:



Though, I have no experience in order to implement this into AWR. I am familiar with 'Import Netlist' in AWR, though that requires a S2P file, SPICE/HSPICE file which this model is just from a PDF... This leads me to the HJ-FET.

The S parameter files are available on the manufacturers website. Though, there are several (9 in total) different S2P files for the one device. I understand that each one is for the device under differing operating conditions, though I don't quite understand how to make use of these within AWR... I have the S2P files imported into AWR, though if I am investigating the device's performance and am not sure of what the operating conditions are going to be, how do I know which of these S2P files I need to use? Am I missing something?

Any feedback is appreciated  :)
 

Offline rfeecs

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Re: AWR SPICE Models
« Reply #1 on: May 30, 2016, 11:37:46 pm »
Looks like that diode model is just for a PN junction diode, the simple diode model, DIODE.  You could use that and add the other extrinsic elements Cp, Ls, Rs in your schematic.

The NE3511S02 is pretty much the lowest noise production FET available for 12 GHz.  It's designed for use at 2V, 10mA.  That's where you are going to get optimum noise figure / associated gain.  You are going to have to pick one S2p file and use it.  I don't really see why you don't know what operating conditions you want to use.

How to use it?  RTFM?  :)


 

Offline tec5cTopic starter

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Re: AWR SPICE Models
« Reply #2 on: May 31, 2016, 12:13:33 am »
Looks like that diode model is just for a PN junction diode, the simple diode model, DIODE.  You could use that and add the other extrinsic elements Cp, Ls, Rs in your schematic.

The NE3511S02 is pretty much the lowest noise production FET available for 12 GHz.  It's designed for use at 2V, 10mA.  That's where you are going to get optimum noise figure / associated gain.  You are going to have to pick one S2p file and use it.  I don't really see why you don't know what operating conditions you want to use.

How to use it?  RTFM?  :)

Thanks for the reply.

It seems that the volterra diode model would be more appropriate than the simple diode model, as the volterra allows for input into parameters of interest that the simple diode model doesn't.

The purpose of these models is for research into trade-offs that need to be considered for low-phase-noise performance of VCOs. While ideally you would use it at 2V, 10mA as you said,  I still need to consider other operating conditions.

You're right though, I too don't see how I didn't know what operating conditions I require.... I blame the lack of food and sleep!  :=\  |O
 

Offline T3sl4co1l

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Re: AWR SPICE Models
« Reply #3 on: May 31, 2016, 12:38:18 am »
I have a netlist model (.CKT / .CIR?) handy for a different varactor; I could write the model for yours if you like.

Hmm, I don't have standard pricing for models, I should think about that...

Tim
Seven Transistor Labs, LLC
Electronic design, from concept to prototype.
Bringing a project to life?  Send me a message!
 

Offline rfeecs

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Re: AWR SPICE Models
« Reply #4 on: May 31, 2016, 02:59:17 am »
The purpose of these models is for research into trade-offs that need to be considered for low-phase-noise performance of VCOs.

First off, the S-parameters are going to tell you nothing about phase noise.  They can only be used for small signal simulation.

My observation is that most low phase noise oscillators up to about 10 GHz use silicon bipolar transistors.  As far as I know, this is because they have low 1/f noise.  The phase noise is caused by 1/f noise that is up-converted by the oscillator to create close in phase noise.

At higher frequencies, HBTs or MESFETs or pHEMTs could be used.  Your HJFET (another name for pHEMT) has great noise figure at 12GHz, but likely not great 1/f noise.

At any rate, to simulate phase noise, you need a non-linear model that includes flicker noise model parameters for your active device.

You might want to look at some examples of simulating oscillators and phase noise, like this one:
https://awrcorp.com/download/faq/english/examples/BJT_Oscillator.aspx
 

Offline G0HZU

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Re: AWR SPICE Models
« Reply #5 on: June 03, 2016, 11:32:53 am »
Quote
Though, I have no experience in order to implement this into AWR.

We have AWR MWO at work and I've used it reasonably often (I prefer Genesys) so I've only got limited experience of importing models to AWR.

Sometimes the models are supplied to me by the device manufacturer in dll library format and they can be pasted into the relevant non linear folder and they will appear in the model library. This is fairly easy to do but (sadly) this isn't the same format as a spice model.

I use the downloadable AWR 'Vendor Libraries' that don't require internet access because our system blocks the online libraries. In this case I've managed to 'fudge' new spice models into these existing vendor libraries by adding the spice model in the relevant library sub folder and then doing some surgery on the xml file to include this file in the list of available models.

This is probably the wrong way to do it and there's almost certainly a much easier way but it seems to work and it only takes a couple of minutes of edit/pasting etc.
« Last Edit: June 03, 2016, 11:35:40 am by G0HZU »
 

Offline rfbroadband

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Re: AWR SPICE Models
« Reply #6 on: August 05, 2016, 05:39:52 am »
if you have a PSpice model in .cir format...save it as .sp (HSpice not s-paramater). Then use the HSpice netlist import function to import the .sp file and you should be able to use the file right away,.

Don't use the built in PSpice import function. It converts the .cir into a rarely used AWR netlist format which is more difficult to use. The HSpice importer keeps the original syntax of the .cir file unchanged, in case you need to modify it.
 


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