- 5th January 2005, 23:44 #1

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## atf36077 model zap file

I have simulate the FET in ADS by using the nonlinear model provided by agilent for LNA (The Gaas FET is ATF54143). The s-parameter from the simulation does not agee well with the measurement s-parameters. I have some doubt about the nonlinear model. how it accurate? In the agilent application note, they use the measured s-parameter for design. Can I conclude that.

1. for small signal amp. LNA -> measured s-parameter is the best.

But how about P1, IP3? can i still use the nonlinear model to predict them?

2. for oscilator, VCO -> I think i still can use measured s-parameter for open loop analysis but I do need a nonlinear model for transient and HB to predict the harmornic and start up. ALso most nonlinear model does not provide the phase noise parameters so it renders the phase noise simulation useless.

3. PA .. I think only load pull work. I dont think any large signal model will work because the environment for parameter extraction is not same as the real environment (i.e. mechanical construction, heat sink, etc.)

I am very frustrated for the nonlinear model. even the V-I curve does not agree well with the data sheet. The model is Curtice 2. (I am frustrated becuase i am using Agilent simulator, Agilent FET and Agilent model, it still does not accurate how can I trust other vender model (such as CEL) )

Any experience which model will be used in what kind of design???

- 6th January 2005, 02:16 #2
## atf-54143 spice

Hi Boy,

I face the same problem as you... I'm using a NEC (CEL) FET. But at least Agilent datasheet provides the parameters used in the nonlinear model, the NEC datasheet I have don't and I'm clueless what they used!

I'm not too sure but you can try to optimise the parameters you have by looking at the ADS tutorial under : example\MW_cct\AModelB..

It'll fit the parameters to the measured results you have I suppose.

- 6th January 2005, 02:16

- 6th January 2005, 03:00 #3

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## fet model

Dear gecky

Thank you, i will try. some CEL data sheet give you the value of all parameters. But if you look carefully, AF and KF will be 0 and 1 respectively, so we cannot simulate phase noise. only few CEL FET which they recommend for OSC design, provide AF and KF. Have you ever use NE3210S01 in any design, i need to know how accurate the model is?

- 6th January 2005, 05:42 #4
## s parameter fet

hi all,most of person here say to use s parameter model that is more accurate than nonlinear model,.i use s par. model in my design

that all

regards

- 6th January 2005, 09:36 #5
## jfet osc designs

Hi abdoeng,

like in your reply to one of my posts, we need Harmonic Balance to ensure there is steady state osc. The S-para model can't be used for this. May I know how you design oscillators? Or all just depends on the accuracy of the nonlinear model?

Thanks!

- 6th January 2005, 12:18 #6
## ads sp pb model fet

Originally Posted by**gecky**

- 6th January 2005, 21:49 #7

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## ne3210s01 1db compression

even in LNA design u need also acurate nonlinear model . to simulate the nonlinearity of the amp

like 1 dB compression point and IIP3

it is a very important specs of the desgin

both models r important

thanks

- 7th January 2005, 00:12 #8

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## sparameters of fet

But the nolinear model is not agree with measured s-parameter model. I have simulate to get the s-parameter table from the non-linear model and compare it to the one in the data sheet. It does not aree well, that is the problem.

- 8th January 2005, 07:00 #9

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## atf-54143 curtice ads model edaboard

if u r biasing the FET according to the data sheet nonlinear model give same s-parameter check your id and vds it shoud be similar as given in s parameter model.

- 8th January 2005, 07:00

- 8th January 2005, 16:26 #10
## nonlinear model

if u r biasing the FET according to the data sheet nonlinear model give same s-parameter check your id and vds it shoud be similar as given in s parameter model.

like boy, I face the same problem... I'm using NE76184A.... checked Vds and Ids and they are as per those for S-para in the datasheet.

Both the nonlinear and S-para model for this FET is available in ADS. You can try and see if you can get it to work. Thanks!

- 8th January 2005, 16:26

- 8th January 2005, 23:38 #11

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## spice s-parameter model connection

dear zeshan102

I have check by DC simulation. it is 100% sure that VD and Id is same as in the data sheet.

Dear

GeckyI will give it a try and let u know.

- 9th January 2005, 04:40 #12

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## ads fet models

Agilent suplies some nolinear modals,you can get it throught its web sit!

- 9th January 2005, 08:45 #13
## ads model hemt

summersonic,

the problem Boy and myself face is that the nonlinear model provided by ADS give very different performance from the datasheet small-sig S. So we are questioning the accuracy/validlity of using these models... but on the other hand, we are left with no choice (for myself at least) because I'm designing an oscillator and the nonlinear model is required. Will be good if you can share your experience with us :)

Thanks!

- 14th January 2005, 12:14 #14

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## osc paramodel

Hi all,

I need nonlinear model of ATF26884 and ATF 36077 from @gilent and NE321S01 from N-E-C. I need this models for simulating VCO at 11GHz . Where to download this ?

Does anybody have measured s-par of this transistors?Are measured s-pars same as s-pars from manufacturers?

- 14th January 2005, 12:39 #15

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## s2p file ne3210s01

u can find the nonlinear model of NE3201so1

www.cel.com

there is a design kit for @DS download it and there r many nonlinear models

- 14th January 2005, 12:49 #16
## ads fet model parameters

I am expecting someone can totally solve these problems in the above .

Thanks !

- 14th January 2005, 22:36 #17
## gaas fet spice model

Originally Posted by**zeshan102**

Added after 6 minutes:

Originally Posted by**sini**

what about u osc.design

- 15th January 2005, 01:39 #18

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## ads fet model

Dear all

i am using AT32033 in design of LNA and oscillator , and i need to know how accurate the sparameter file contianed in @DS also i need to know the nonlinear model in @DS or not

thanks

- 16th January 2005, 01:37 #19

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## cel fet nonlinear models

http://www.home.agilent.com/cgi-bin/...arch_for_go=Go

There ia a spice model there. U cal try to import the spice model to ADS and compare it with the measured S-parameter (also can be download from the site in s2p format) Also the agilent always mention

"While models in this library reflect close similarity to device performance, simulation is only a supplement to lab evaluation. Model performance in general will reflect typical specs for a device, but some aspects of performance may not be modeled fully. Care has been taken in their preparation, however, we cannot be responsible for correct application on any and all computer systems. Agilent Technologies reserves the right to improve these models without prior notice. Refer to the datasheet for guaranteed performance and design guidelines."

it means that you use it at your own risk.

- 16th January 2005, 12:06 #20
## ne3210s01 ads

hi,all,thanks all for care,but i ignore how to import spice file to ads,

pls tell me how,that i am new in using ads2003a

regards

i use atf36077 ,here its