Process Variation simulation

[nile_king]

Hi
Dear All;

I wanna ask how to simulate the process variation for ref current using cadence and i have no licence for monte carlo
in changeing the models of the transistors, res, BJT, ... in the model library, change it to what??

thanks

 

[cristianb]

use corner models in you simulation. you can do this by seleting from ADE SETUP->model libraries an here select the corner switch.

 

[nile_king]

Thank you for ur help
I also need to know what 2 write
for example i know the model changes for CMOS and BJT
what about the res and cap ...

thanks

 

[maxwellequ]

The corner models for the transistors are provided by the foundry.

For resistors/capacitors in most cases either there are models from the foundry or there is documentation stating the variations. In case you do not have this info, you may use +/- 20 % to +/- 25 % of absolute value variation (typical range).

 

[dog1357]

in mentographics, u may use some script to change all the resisitor and capacitor value at one time, not sure candence get this or not.

 

[cristianb]

according to the technology switch you select all device models will be altered. the name of the switch differs from foundry to foundry. Usually these are:
ff-> fast
ss-> slow
fs->fast slow
sf-. slow fast

You show find in the technology forder a file that contain an index of the models used in that technology and there these switches should be specified.