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<!channel> Since Open_pdks is now the default way of using xschem with the skywater-pdk i made a <https://www.youtube.com/watch?v=KgBLByOkJxA|new video> showing how to setup xschem. Basically just follow the instructions on <http://opencircuitdesign.com|opencircuitdesign.com>, build xschem from its github sources and you are done.

If I already installed the skywater_pdk, could I just install from the openpdk part ? This new skywater_pdk installation link is different from the original one?
Thanks!

Yes, the skywater-pdk install directory is used by open_pdks. In the configure stage of open_pdks you give the path of your skywater-pdk install:
$ ./configure *--enable-sky130-pdk=/your/install/path/skywater-pdk* --prefix=/where/to/install/open_pdks

then if you create a schematic directory and copy the xschemrc file as shown in the video, xschem will automatically use the new open_pdks provided spice models.
I suggest now everyone to use open_pdks since patches and fixes are added to the original skywater-pdk files.

Thanks Stefan!!! :slightly_smiling_face: 

Are there any special steps needed to use ngspice with this method? I remember in your previous video ngspice was installed using the autogen.

No, for ngspice installation remains the same, you may refer to previous video for that.

Hi, <@U027D6XAE1L> I think you should generate the netlist from xschem, then go to the directory where the netlist is generated and try to run ngspice manually on your netlist:
`ngspice -i your_netlist.spice -a`
So you don't have xschem in the loop since this seems more a ngspice issue.
Did you try to do a '`setplot noise1`' before giving the `plot` command?

My question is how to plot noise PSD in y axis in logrithemic from the figures and ngspice command as above?

Try to give 'ylog' as last parameter to the plot command

ngspice is limited in plotting ability, if you want something better you may try gaw or 'bespice' (bspwave) from analog flavor, it has a free non commercial evaluation  license for one year

in the ngspice plot window if you click the right mouse button and drag a zoom rectangle a new window is opened with the requested area...