How to set up initial conditions for post-layout simulation?

[nxing]

post-layout simulation

Hello everybody,

I am simulating my circuit with "extracted", however, I need to setup some initial conditions in order to make the system converge. Can anybody tell me how to do that? I know how to set them up in schematic.

Thanks in advance!

 

[Hughes]

post-layout simulation

Just like what you do in schematic simulation if you are using Analog Artist to simulate a diva extracted view. If you are simulating the extracted in command-line mode, use ".IC" statement in the netlist file.

 

[nxing]

post-layout simulation

Hi hughes,

Thanks for your reply. The problem is that it seems that I can not select the net in extracted cellview like I did in schematic.
Any suggestion?

Regards

 

[Hughes]

post-layout simulation

Maybe you didn't save the interconnect information to the extracted view. Make sure there is a saveInconnect statement in your extract rule file. If it exists, then check your technology file and make sure there are net purposes defined for the interconnect layers.

Good luck.

 

[nxing]

post-layout simulation

Hi Hughes,

Thanks for your reply. There is a saveInterconnect statement in the extract rule file. However, I didn't find there is a netPurpose defined in the technology file. Under this situation, do you know how to deal with it?

Thanks

 

[Hughes]

Re: post-layout simulation

1. Find which layer/purpose pairs (LPP) you need to add.
If your saveInterconnect looks like:
saveInterconnect(nsd psd cont m1 v1 m2)
then you should define LPP's: nsd net, psd net, cont net, m1 net, v1 net, and m2 net.
If your saveInterconnect looks like:
saveInterconnect((nsd "NP") (psd "PP") (cont "CONT") (m1 "M1") (v1 "V1") (m2 "M2"))
then you should define LPP's: NP net, PP net, CONT net, M1 net, V1 net, and M2 net.

2. In CIW, choose menu "Technology File / Layers ...", add the above-mentioned layer/purpose pairs. If the layer name already exists, only new purposes should be added for those layers. Otherwise, new layers should be added. The only difference is you should assign a new layer number in the latter case.
You may also add those LPP's in a .tf file.

 

[dumbfrog]

Re: post-layout simulation

Try to ramp up your power or play around your .option parameters
Here is a good paper on convergence problem