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Referencing a model, not a model instance

itos

Hello,

I found the post about disabling flicker noise with alter in this forum and I got it working:

turnOffFlicker1 alter mod=N15.xmmaster.lvtnfetacc param=nfalw value=0
turnOffFlicker2 alter mod=N15.xmmaster.lvtnfetacc param=nfblw value=0
turnOffFlicker3 alter mod=N15.xmmaster.lvtnfetacc param=nfclw value=0

If I reference the model (i.e. lvtnfetacc and masterlvtnfet from the model files) I get:

ERROR (SFE-1997): "disable_flicker.scs" 6: turnOffFlicker4: parameter `mod': Invalid model name `lvtnfetacc' was given as value of parameter `mod'.

I tried all possible variations. Unfortunately the model files are so nested that I don't know what's going on. Generally there is a subckt for "lvtnfet" which instantiates instance xmmaster of lvtnfetacc. lvtnfetacc itself is a subckt which instantiates m1. m1 is a reference to the model lvtnfetacc of type utsoi which has the parameter nfalw etc:

sub

Please help me to set nfalw to zero globally without listing all instances.

Also, is it possible to list multiple mod/param/value pairs at once so that I do not need to create thousands of turnOffFlickerXX lines that go up to 1000?

Thank you!

Parents
  • Andrew Beckett

    OK, a couple of things here. First, the reporting of noiseoff_type in the log file. This is not the friendliest reporting in the log file, but the way that all options in spectre which have names as option values work is that they're all actually enumerated. So if I look at "spectre -h options" for this option:

    33 noiseoff_type=all
    The noiseoff_type defines the noise sources which are
    disabled by the noiseon/off_inst option. The default
    value is all. Possible values are thermal, flicker,
    shot, ign, and all.

    This means that thermal=0, flicker=1, shot=2, ign=3 and all=4. It will report these numbers - just a single number if one is selected; if more than one is selected it will show (say) [0 1] to indicate that thermal and flicker has been selected. 

    There's a (strong) argument to say we should report this better using the words corresponding to the choices. You could (for example) specify these options as numbers, but the words are much more friendly.

    As for the flicker noise not working, I just tested this (with MMSIM15.1 ISR10) using bsim4 models, and I could disable flicker noise for my subckt (so it doesn't just have to be a leaf instance) and also thermal (I tried thermal and flicker). I did find that the flicker noise for one of the unsupported devices still appeared within that subckt, but for the transistors it was gone.

    Now, according to the second link I posted above, utsoi is supposed to be one of the supported devices (that's the model you're using from your circuit inventory), so I'd expect it to work. Unfortunately I don't have any utsoi models handy that I can try (and I'm rather short of time this week).

    So, I'd suggest that you:

    1. Try with a newer versions still (maybe the initial version didn't support utsoi; the feature was officially rolled out in SPECTRE161 I believe, so it may be worth checking a SPECTRE161 version instead of MMSIM151).
    2. If that doesn't work, contact customer support to see if we can identify what is going wrong; then an AE can spend time on investigating it.

    Thanks,

    Andrew.

Reply
  • Andrew Beckett

    OK, a couple of things here. First, the reporting of noiseoff_type in the log file. This is not the friendliest reporting in the log file, but the way that all options in spectre which have names as option values work is that they're all actually enumerated. So if I look at "spectre -h options" for this option:

    33 noiseoff_type=all
    The noiseoff_type defines the noise sources which are
    disabled by the noiseon/off_inst option. The default
    value is all. Possible values are thermal, flicker,
    shot, ign, and all.

    This means that thermal=0, flicker=1, shot=2, ign=3 and all=4. It will report these numbers - just a single number if one is selected; if more than one is selected it will show (say) [0 1] to indicate that thermal and flicker has been selected. 

    There's a (strong) argument to say we should report this better using the words corresponding to the choices. You could (for example) specify these options as numbers, but the words are much more friendly.

    As for the flicker noise not working, I just tested this (with MMSIM15.1 ISR10) using bsim4 models, and I could disable flicker noise for my subckt (so it doesn't just have to be a leaf instance) and also thermal (I tried thermal and flicker). I did find that the flicker noise for one of the unsupported devices still appeared within that subckt, but for the transistors it was gone.

    Now, according to the second link I posted above, utsoi is supposed to be one of the supported devices (that's the model you're using from your circuit inventory), so I'd expect it to work. Unfortunately I don't have any utsoi models handy that I can try (and I'm rather short of time this week).

    So, I'd suggest that you:

    1. Try with a newer versions still (maybe the initial version didn't support utsoi; the feature was officially rolled out in SPECTRE161 I believe, so it may be worth checking a SPECTRE161 version instead of MMSIM151).
    2. If that doesn't work, contact customer support to see if we can identify what is going wrong; then an AE can spend time on investigating it.

    Thanks,

    Andrew.

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