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Netlist extractor SPICE

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Netlist extractor SPICE#

This notebook demonstrates how to extract the SPICE netlist of a Component or a GDS file using gdsfactory. It uses the :func:~get_netlist and :func:~get_l2n functions from the gplugins.klayout module to extract the netlist and connectivity mapping, respectively. It also uses the plot_nets function to visualize the connectivity.

import pathlib

from gdsfactory.samples.demo.lvs import pads_correct, pads_shorted

from gplugins.klayout.get_netlist import get_l2n, get_netlist
from gplugins.klayout.plot_nets import plot_nets

Sample layouts#

We generate a sample layout using pads_correct and write a GDS file.

c = pads_correct()
gdspath = c.write_gds()
c.plot()

2024-05-10 10:16:51.656 | INFO     | gdsfactory.component:_write_library:2003 - Wrote to '/tmp/gdsfactory/pads_correct.gds'
../_images/c3b5f5c7a743ffaa876b2fa9793010810170af5201f5a6d2efdad7cb69ada2e5.png

We obtain the netlist using KLayout by simply calling the :func:~get_netlist function from the gplugins.klayout module. The function takes the path to the GDS file as an argument and returns the netlist as a kdb.Netlist object.

netlist = get_netlist(gdspath)
print(netlist)

Wrote '/home/runner/work/gplugins/gplugins/gplugins/klayout/layers.lyp'
Wrote '/home/runner/work/gplugins/gplugins/gplugins/klayout/d25/generic.lyd25'
Wrote '/home/runner/work/gplugins/gplugins/gplugins/klayout/tech.lyt'
circuit straight_41ebfd0f ($1=$1);
end;
circuit straight_5ac9171b ($1=$1);
end;
circuit straight_96ebe305 ($1=$1);
end;
circuit bend_euler_d6b78123 ($1=$1);
end;
circuit straight_eeb28574 ($1=$1);
end;
circuit pad ($1=$1,$2=$2);
end;
circuit pads_correct ();
  subcircuit pad $1 ($1='tl,tr',$2=tl);
  subcircuit pad $2 ($1='tl,tr',$2=tr);
  subcircuit pad $3 ($1='bl,br',$2=br);
  subcircuit pad $4 ($1='bl,br',$2=bl);
  subcircuit straight_96ebe305 $5 ($1='tl,tr');
  subcircuit bend_euler_d6b78123 $6 ($1='tl,tr');
  subcircuit straight_5ac9171b $7 ($1='tl,tr');
  subcircuit bend_euler_d6b78123 $8 ($1='tl,tr');
  subcircuit straight_41ebfd0f $9 ($1='tl,tr');
  subcircuit straight_eeb28574 $10 ($1='bl,br');
end;

The connectivity between the components in the GDS file can be visualized using the :func:~plot_nets function from the gplugins.klayout module. The function takes the path to the GDS file as an argument and plots the connectivity between the components in the GDS file.

l2n = get_l2n(gdspath)
cwd = pathlib.Path.cwd()
filepath = cwd / f"{c.name}.txt"
l2n.write_l2n(str(filepath))
plot_nets(filepath)

Wrote '/home/runner/work/gplugins/gplugins/gplugins/klayout/layers.lyp'
Wrote '/home/runner/work/gplugins/gplugins/gplugins/klayout/d25/generic.lyd25'
Wrote '/home/runner/work/gplugins/gplugins/gplugins/klayout/tech.lyt'
../_images/557886be63e7e6079b872f23a6c71c862bbd4a6ede137fc7ce4c888c3cda47ef.png

The same steps as above are done for a shorted case.

c = pads_shorted()
gdspath = c.write_gds()
c.plot()

2024-05-10 10:16:52.028 | INFO     | gdsfactory.component:_write_library:2003 - Wrote to '/tmp/gdsfactory/pads_shorted.gds'
../_images/992da5a9cb7f225a419cb46bf1abac945ab51713d6d4ea73d21084879c9e8fc2.png 
netlist = get_netlist(gdspath)
print(netlist)

Wrote '/home/runner/work/gplugins/gplugins/gplugins/klayout/layers.lyp'
Wrote '/home/runner/work/gplugins/gplugins/gplugins/klayout/d25/generic.lyd25'
Wrote '/home/runner/work/gplugins/gplugins/gplugins/klayout/tech.lyt'
circuit straight_41ebfd0f ($1=$1);
end;
circuit straight_5ac9171b ($1=$1);
end;
circuit straight_96ebe305 ($1=$1);
end;
circuit bend_euler_d6b78123 ($1=$1);
end;
circuit straight_eeb28574 ($1=$1);
end;
circuit pad ($1=$1,$2=$2);
end;
circuit pads_shorted ();
  subcircuit pad $1 ($1='bl,br,tl,tr',$2=tl);
  subcircuit pad $2 ($1='bl,br,tl,tr',$2=tr);
  subcircuit pad $3 ($1='bl,br,tl,tr',$2=br);
  subcircuit pad $4 ($1='bl,br,tl,tr',$2=bl);
  subcircuit straight_96ebe305 $5 ($1='bl,br,tl,tr');
  subcircuit straight_5ac9171b $6 ($1='bl,br,tl,tr');
  subcircuit straight_eeb28574 $7 ($1='bl,br,tl,tr');
  subcircuit bend_euler_d6b78123 $8 ($1='bl,br,tl,tr');
  subcircuit straight_5ac9171b $9 ($1='bl,br,tl,tr');
  subcircuit bend_euler_d6b78123 $10 ($1='bl,br,tl,tr');
  subcircuit straight_41ebfd0f $11 ($1='bl,br,tl,tr');
end;

l2n = get_l2n(gdspath)
filepath = cwd / f"{c.name}.txt"
l2n.write_l2n(str(filepath))
plot_nets(filepath)

Wrote '/home/runner/work/gplugins/gplugins/gplugins/klayout/layers.lyp'
Wrote '/home/runner/work/gplugins/gplugins/gplugins/klayout/d25/generic.lyd25'
Wrote '/home/runner/work/gplugins/gplugins/gplugins/klayout/tech.lyt'
../_images/557886be63e7e6079b872f23a6c71c862bbd4a6ede137fc7ce4c888c3cda47ef.png
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