[SOLVED] LVS Errors due to Dummy transistors

[MohEllayali]

lvs dummy

Hello,

I got errors on LVS due to dummy transistors, I read a bit about that , and figured out that I need to specify some filtering options on the LVS deck.

I am afraid of doing things in a wrong way , so can somebody give me some explanations please on the different options

LVS Filter unused option
LVS Filter unused MOS
LVS Filter unused BIPOLAR
LVS Filter unused CAPACITORS

there are letters such as AB RC etc that don't make sens for me

I am using Caliber LVS

Many thanks

 

[kumarans]

dummy lvs

Hai my friend it means the LVS option will consider to be not present i.e. when the dummy transistors are not present in the schematic and we us this option to clear LVS, so that the tool will ignore the dummies.

 

[erikl]

It's a good practice to instance (and route) the dummies in the schematic, too. So you always have a good overview about possible spare devices, and you don't have to wrestle with LVS rules' filtering.

 

[MohEllayali]

Okay guys thank you ... I was actually looking for a good document talking about the different options !!! but I get stuck and eventually draw the dummy transistors on schematic ...
You said that it's a good habit to do so , but imagine that you have ,.. let say 100 transistors ... it will be tedious to draw them by hand , isn't it ??
many thanks

 

[wpchan05]

well. if you use an instance name (eg NM<100:1>) for your dummy devices, you can just place one instance in schematic.

 

[deepak242003]

alternatively you can directly add dummies in netlist.....

 

[sandeep_torgal]

It's a good practice to instance (and route) the dummies in the schematic, too. So you always have a good overview about possible spare devices, and you don't have to wrestle with LVS rules' filtering.

Agree with erikl. It even helps designers to use the dummies for the design changes if they dont want to re-layout at the end stages.

Regards,
Sandeep