for the same circuit extraction was done in calibre.... now wehn I did same extraction wiht assura,it is showing large parasitic resistance. for few nets.........
It seems it is giving more resistance.......
I tried wiht two inverters one wiht long net(400um) and other small with small (10um) in the same schematic.....still it show the max parasitic error of 158ohms.. which isn ot possible as we are using metal layers... moreover it is showing more resistance for every trace..( i guess)..
we dont have calibre license anymore....we shifted to assura....
It seems it is giving more resistance.......
I tried wiht two inverters one wiht long net(400um) and other small with small (10um) in the same schematic.....still it show the max parasitic error of 158ohms.. which isn ot possible as we are using metal layers... moreover it is showing more resistance for every trace..( i guess)..
Hi deepak,
could it be possible that assura extracts inductance and tells you the equivalent impedance values for a standard frequency (let's say: 1GHz)?
Can you check the extract rules for that? Did you check the connectivity rules? Given the connect switch?
Possibly the node that this resistor is attached has no reference to vss so the netlist
produced just inserts a huge resistor to compensate for this. Anyway i cannot see how such a big resistor can affect results. Are the extracted simulation any different?
Sorry, I mixed it up with the LVS netconnect switch you mentioned in this topic. But the extract command also uses switches which may be necessary.
Cheers, erikl
yes , we are not getting any output.... possibly no voltage is reaching at desired circuit...... we cant predict anything until this issue is resolved..
Added after 10 minutes:
erikl said:
Sorry, I mixed it up with the LVS netconnect switch you mentioned ..
That was resolved wiht modification of rule deck.. there only VDD and VSS was declared and power and in actual layout we were using AVDD25 and AVSS 25......
and ofcoure,schematic, we were using AVDD25 and AVSS25
erikl said:
But the extract command also uses switches which may be necessary.
l
Hi deepak,
try to locate one of these high-ohmic series resistances in your layout, including its connections thru various layers. Perhaps there's a missing via or layer connection statement in the extract rules?