Choosing appropriate SPICE models

[hobbyiclearner]

Hi,

I have to conduct Analog CMOS based training to under graduate level learners. The training will include simulating MOS based simulation of one transistor & multi transistor circuits up to 2 stage op amps. In this connection, I wanted to know which level of MOS transistor model parameters will be sufficient to demonstrate the various characteristics. Someone told me that level 1 may be a little naive. If that is true, pls. suggest an appropriate SPICE model level accordingly. Pls. keep in mind that the model parameters need to be freely available.

Looking forward to your responses.

Thanks,
Hobbyiclearner

 

[pancho_hideboo]

MOS Level 3

 

[hobbyiclearner]

MOS Level 3

Thanks for your reply. Can you suggest a suitable technology node as well ? (350 nm/ 180 nm etc)? Also, could I request you to point me towards a suitable level 3 model file (typical) which I can use in this context. There are a lot of level 3 MOS model files on the net creating confusion for me.

Regards,
Hobbyiclearner

 

[pancho_hideboo]

Can you suggest a suitable technology node as well ? (350 nm/ 180 nm etc)?

MOS Level 3 is not suitable for such short L MOS.
Even bsim1 is also not suitable.
bsim3 is used for such L.

What simulator do you use ?

 

[hobbyiclearner]

I am planning on LTSpice (could you suggest a free online/offline simulator also?) . Its Ok if I have to increase the value of L. I just need a suitable tech node and corresponding model files for running general analog simulations. Thanks for taking interest in my query.

Arvind Gupta.

 

[pancho_hideboo]

If you aim at training of IC design, try Glade.
http://peardrop.co.uk/
**broken link removed**

If your concerns are only simulation, see https://www.edaboard.com/showthread.php?388267

 

[hobbyiclearner]

Thanks. As of present, I will just use the APDK model card with LTSpice. BTW do you happen to know the supply voltage of this technology. I was unable to find it in the associated pdf. Attaching it here for your ready reference.

View attachment apdk_cnm25_v2020_04_19.pdf

Regards,
Hobbyiclearner.

 

[pancho_hideboo]

See https://www.edaboard.com/showthread.php?346680
2.5um Process, so Vdd=5V.

 

[vivekroy]

There is the Microcap simulator from Spectrum Software. It used to be an industrial grade simulator until Spectrum went belly up. They have made their simulator free (not open source).

 

[hobbyiclearner]

I observed one funny thing in the model card. The 'tpb' parameter has been repeated twice in the pmos model parameters list. Not so for the case of nmos parameter list. Attaching the model card here for your reference. Do you think the model card is reliable? though i wont be fabricating any design through it, it needs to be factually correct.

View attachment cnm25mod.txt

Regards,
Hobbyiclearner.

- - - Updated - - -

OK. I am looking for model card for analog simulation purpose; not free simulators. Anyways thanks for your reply. Do you have any model card which you can provide?

Regards,
Hobbyiclearner

 

[pancho_hideboo]

The 'tpb' parameter has been repeated twice in the pmos model parameters list.

It is no problem. Last one is effective

+ TPB     = 0
+ TPB     = 1
+ TPB     = 2

In this case, 2 is assigned to TPB.

I am looking for model card for analog simulation purpose

https://pages.hmc.edu/harris/cmosvlsi/4e/index.html

 

[hobbyiclearner]

https://pages.hmc.edu/harris/cmosvlsi/4e/index.html

Thanks. This would help. I suppose the operating voltage will be 1.8 v. Also, in the given link, there is a process characterization kit. How to use it (though I can get the main values directly from the model deck - I am just curious to know how to use the characterization kit). It seems to be a SPICE netlist. Pls. tell me the usage in terms of LTSPICE if possible.

Regards,
Arvind Gupta