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Insufficient memory to run PSS analysis - how to resolve?

apaj

Hello.

I did see that there are three recent threads with very similar titles, but - unfortunately, with completely different problems described.

I use up-to-date MMSIM and IC5 (2012_2013 package installed on a 32 bit machine) and I have given a swap file to the PSS analysis. I am trying to get IIP3 post-layout simulation to run for my circuit (QRC used for extraction). I want it measured at 8 and 9 GHz with 200 MHz harmonics. I do only 6 steps for signals of power in the range of -20:5 dBm.

Nevertheless, the simulation breaks telling me - insufficient memory. During the simulation, it doesn't really use the file I gave it (<path>/Desktop/pss_swap - it's always 0 bytes). What it actually does is that it creates about twenty files called pss_swap_0, pss_swap_1, and so on, each of them about 1.2 GB. And it does this for every point of calculation.

Now, my question is, is it possible (and how?) to overcome this? If I choose a higher limit for extraction my S-parameters change, so I can not go higher on this. Less than 6 points... does it really make sense? Number of harmonics must remain the same since I need it calculated at certain frequencies. 

Do you have any suggestions how to get this done?

Thank you very much for your time and effort.

Parents

  • First of all, I apologize for a delayed answer - I was out of office for a couple of days.

    Thank you very much for your advices and explanations. I tried to follow your instructions on running the qpss HB analysis - with the same output: Insuficient memory.

    What I am working on is a purely academic project, so I don't have a problem sharing the log files - I just want to have it running.

    Here is the line about the software version:

    spectre (ver. 5.10.41.121508 -- 15 Dec 2008).

    Here are some warning that might be interesting, and I couldn't get the hang of them:

    qpss: `flexbalance' is not a valid parameter for an instance of `qpss'.
            Ignored.
    qpss: `oversample' is not a valid parameter for an instance of `qpss'.
            Ignored.

    Namely, for some reason it doesn't like the oversample to be 1 - and I read here that it should be 1... Flexbalance, I couldn't find - what is it?

    Here is the circuit inventory:

    nodes 247224
    equations 247257
    ahdl simulator 1    
    bsim3v3 8    
    capacitor 100526
    diode 52   
    inductor 12   
    port 2    
    resistor 310279
    respoly_va 8    
    vsource 3  

    This number of almost 250k  equations looks really scary... But, as I mentioned a couple of posts ago, it's what I get after QRC extraction. I tried sett ing the parasitics limit to higher values (so I have less parasitics) but then the results start to change and look much better than when all of the small ones are included. So, I guess I don't have a choice here, it must be this much... Right?

    Also, please find attached the screenshot of my qpss analysis. Am I doig it the right way?

    Thank you very much for you effort.

Reply

  • First of all, I apologize for a delayed answer - I was out of office for a couple of days.

    Thank you very much for your advices and explanations. I tried to follow your instructions on running the qpss HB analysis - with the same output: Insuficient memory.

    What I am working on is a purely academic project, so I don't have a problem sharing the log files - I just want to have it running.

    Here is the line about the software version:

    spectre (ver. 5.10.41.121508 -- 15 Dec 2008).

    Here are some warning that might be interesting, and I couldn't get the hang of them:

    qpss: `flexbalance' is not a valid parameter for an instance of `qpss'.
            Ignored.
    qpss: `oversample' is not a valid parameter for an instance of `qpss'.
            Ignored.

    Namely, for some reason it doesn't like the oversample to be 1 - and I read here that it should be 1... Flexbalance, I couldn't find - what is it?

    Here is the circuit inventory:

    nodes 247224
    equations 247257
    ahdl simulator 1    
    bsim3v3 8    
    capacitor 100526
    diode 52   
    inductor 12   
    port 2    
    resistor 310279
    respoly_va 8    
    vsource 3  

    This number of almost 250k  equations looks really scary... But, as I mentioned a couple of posts ago, it's what I get after QRC extraction. I tried sett ing the parasitics limit to higher values (so I have less parasitics) but then the results start to change and look much better than when all of the small ones are included. So, I guess I don't have a choice here, it must be this much... Right?

    Also, please find attached the screenshot of my qpss analysis. Am I doig it the right way?

    Thank you very much for you effort.

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