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Simulators >> Circuit Simulators >> spectre assert
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Message started by danmc on Jan 24^th, 2008, 6:14am

Title: spectre assert
Post by danmc on Jan 24^th, 2008, 6:14am

can anyone give an example of using spectre assert statements to check for Vds breakdown on MOS devices?

model mynmos bsim3v3 {.....}
model mypmos bsim3v3 {.....}

// netlist involving instances to mynmos and mypmos here

// the assertions

mynmos_vds_check assert mod=mynmos param=Vds min=-5.0 max=5.0 message="NMOS Vds breakdown" level=warning
// similar thing for mypmos

// dcOp and also tran analysis

dc dc .....
tran tran .....

so I do this and I just get some complaints about spectre not really knowing what I mean by "Vds" in the param= line.

I tried playing around with the primitive=bsim3v3, but I don't want my asserts to catch all bsim3v3 devices, only the models 'mynmos' and 'mypmos'.

Thanks
-Dan

Title: Re: spectre assert
Post by danmc on Jan 24^th, 2008, 9:10am

ok, after much messing around and studying the netlist produced with using the "device check..." stuff from the GUI, it seems that the assertions were working but writing to the psf file instead of spectre.out. So I'm making progress. Now I'm stuck on inline subcircuits. 'mymod' (not listed in my original post) is an inline subckt and I want to impose limits on either the terminal voltages or perhaps some internal voltages. But the 'inline' bit seems to cause a problem. If I use mod=mymod or sub=mymod I get a complaint that the model or subckt master doesn't exist. I couldn't seem to find reasonable choices in the GUI for those inline subckts either.

Title: Re: spectre assert
Post by achim.graupner on Jan 24^th, 2008, 10:25am

Hi danmc,

I struggled with both subckt an inline subckt in modelcards when using assertions. I have reported the problem to Cadence but have not answer yet.

Regards,
Achim

Title: Re: spectre assert
Post by sheldon on Jan 25^th, 2008, 4:41am

Greetings,

Which version of MMSIM are you using? Device checking seems
to works by device model in MMSIM62 USR1. The menu includes
options for subcircuits so they are probably working also.

Best Regards,

Sheldon

Title: Re: spectre assert
Post by achim.graupner on Jan 25^th, 2008, 5:09am

Hi,
> Which version of MMSIM are you using? Device checking seems
> to works by device model in MMSIM62 USR1.
indeed

> The menu includes
> options for subcircuits so they are probably working also.
unfourtunately not (neither subckt nor inline subckt in modelcard)

As soon I get news from Cadence I will post here,

Regards,
Achim

Title: Re: spectre assert
Post by Moshtaque on May 17^th, 2010, 5:43pm

Does anybody know how to solve the above problem? Inline subckt used as mod causing the assert to report "model not found. "