Hi, I am doing a layout in Magic in sky130nm pdk, After extract all, ext2spice. I did LVS in netgen. I am not sure what the following lines mean. ...." Class: c instances: 13 Class: **FLOATING instances: 10" Any idea how to clean this??

@Antaryami Panigrahi Looks like you might be using an extracted netlist that contains parasitic capacitors. Try using

ext2spice lvs

before

ext2spice -o …

. Also when sharing LVS results, be sure to include the full command that you use to run LVS.

@Mitch Bailey I've used the following command in netgen:

Although either way will work, it would be nice to have the layout first like in openlane (think layout vs schematic).

@Mitch Bailey I would like to know what are the causes behind the message in netgen : Class: c instances: 13 Class: **FLOATING instances: 10. @Tim Edwards

Parasitic capacitors in the extracted spice netlist.

Thanks @Mitch Bailey, any way to track them down? In the summary of LVS these 23 things gets added to the number of devices in the layout and device mismatch appears.

The lines that begin with

cap

are parasitic capacitors. Use

ext2spice lvs

before writing your extracted netlist to remove them.

Great...let me try

Please show all of the commands that you are using to extract your layout.

I write --extract all -- ext2spice lvs-- in Magic. then in netgen i used the following command. lvs /home/jagaatp/Desktop/Analog/Work1/mag/Jaga_Pass_Tran.spice /home/jagaatp/Desktop/Analog/Work1/mag/Jagannath_Pass_tran.spice /usr/local/share/pdk/sky130A/libs.tech/netgen/sky130A_setup.tcl

How about this?

extract no all ;# clear all options
extract unique ;# do not allow virtual connections
extract

ext2spice lvs
ext2spice -o <topcell>.spice <topcell>.ext