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Design >> Analog Design >> BSIM3 noise model flag, noimod, and PNOISE
https://designers-guide.org/forum/YaBB.pl?num=1120506149

Message started by ethan on Jul 4^th, 2005, 12:42pm

Title: BSIM3 noise model flag, noimod, and PNOISE
Post by ethan on Jul 4^th, 2005, 12:42pm

Hi there

Do you know where I can find noise model flag, noimod, in my technology mode file (*.scs) for spectre ?

Since I would like to whether noimod=1 or others in order to check my PNOISE simulation results for flicker noise. Right now, I couldn't see flicker noise in my PNOISE simluation.

I have checked my TSMC 0.35um mm0355v.scs (TSMC SPICE MODEL for 0.35 MIXED MODE PLOYCIDE ) and didn't find it. Is it in spectre simultor iteself or somewhere else?

Thank you for your time.

ethan

Title: Re: BSIM3 noise model flag, noimod, and PNOISE
Post by Paul on Jul 5^th, 2005, 1:28pm

Ethan,

the noise parameters are usually included in the transistor model file, surprised to hear they are missing in TSMC 0.35. Are you sure about this, this is a stable mixed-signal technology, so I would certainly expect noimod to be set. Have a look at the following link for a conventional model:
http://www.eecg.toronto.edu/~johns/nobots/courses/ece1392/typ_035.mdl

Be aware AF and KF must be set to get flicker noise in the noise simulations.

Paul

Title: Re: BSIM3 noise model flag, noimod, and PNOISE
Post by ethan on Jul 5^th, 2005, 9:21pm

Paul,

Thank you for your reply.

I even doubt the transistor model file we got. My supervisor said he got whole designkit from MOSIS. But I couldn't find:
noimod
noia
noib
..
af
kf

Maybe I will try to add them inside with certain calculated value.

My question here is that I use TSMC 0.35 technology with 5v supply. So the general parameters from the link you post can not be directly applied, right?

ethan

Title: Re: BSIM3 noise model flag, noimod, and PNOISE
Post by Geoffrey_Coram on Jul 6^th, 2005, 7:29am

One need not find AF or NOIMOD in the model file, since one can get noise from their default values (1.0 and 1, respectively). However, using the default NOIMOD=1, one must specify a value for KF to get flicker noise.

NOIMOD=2 or 3 uses the NOIA, NOIB, NOIC parameters, which have default values that generate flicker noise; however, they are probably not correct for your particular process (nor would the parameters from that link necessarily be correct, though the file name does seem to indicate that it's at least the right technology (0.35u)).

Title: Re: BSIM3 noise model flag, noimod, and PNOISE
Post by Paul on Jul 8^th, 2005, 1:32pm

I did not intend to pretend these parameters could correspond to the TSMC process. The idea was to show the usage of the AF and KF parameters and luckily Google gave a link to a 0.35u process ;)

I am not affiliated with the group hosting this link and I have no idea what foundry process these parameters correspond to. To see if it corresponds to your process, you can nonetheless compare some device parameters like VTH0 and UA-UC.

Ethan, maybe you find some additional information in the DK documentation, the models do not always contain flicker noise information by default.

Good luck

Paul