!!!!!!!ADS2002 simulate question!

[Needbias]

when I use ads2002's HB simulator to analyse a PA,there comes a error message:
can't sweep to design level,please decrease the maxshrinkage and resimulate the circuit......but, however I change the maxshrinkageand the parameter of the circuit,the message still.
Are there anyone encounter this problem and does who know how to get a solution?
Thx.

 

[mesfet]

you may first decrease your input power level. You encounter the error message because the input power of your circuit is too large, your circuit is driven into strongly nonlinear region and HB algorithm fail to converge

 

[Needbias]

you may first decrease your input power level. You encounter the error message because the input power of your circuit is too large, your circuit is driven into strongly nonlinear region and HB algorithm fail to converge

I think it's not just because the power level.For some reason,I want to check the IP3 and the output power of a PA,so I must sweep the power from a lower level to higher level,the analyse seems no problem in senrenda8.7.But in ads2002,the problem always,I'm annoyed by this for a long time.

 

[mesfet]

For my experience, the IP3 figure simulated from senerade and ads are not much useful because of the inaccurate nonlinear model.

have you checked the p1dB of your amp in ads2002? For just several dB exceed P1dB, HB analysis should be ok.

Also, how many orders you take into consideration. 5 is already ok for 2-tone HB.

 

[Needbias]

Thx for your advice.But how do you know exactly the p1dB,or just try once by once to get and how can you learn the nonlinelity properties of the PA in the saturation region ?
For me,I think the LSSP HB simulator should simulate this but acturally it can't.
ps:I have already decrease the order consideration to 2,but the problem still.[/quote]

 

[mesfet]

you may sweep the input power for finding the P1dB.
You may try 3,5 or 7 orders, order 2 doesn't make sense unless you have to consider harmonic.