pyNgSpice/examples/SkywaterOpenSourcePDK

* simple examples using Skywater PDK



PDK sources:

https://github.com/google/skywater-pdk

http://opencircuitdesign.com/open_pdks/



Examples are: a simple inverter, and a benchmark circuit ISCAS85 C7552 with ca. 15k transistors.

These examples serve as low level starters with given ngspice netlist. If you are to design a circuit,

you will be better off with a GUI atop ngspice like XSCHEM, see 

http://repo.hu/projects/xschem/xschem_man/tutorial_run_simulation.html and many other web sites and videos.



How to run the circuits in ngspice:



Edit the input files for correcting the path to the Skywater library, as it is user and OS specific.



Create a file .spiceinit in your HOME directory (or in this project directory). 

It should contain the following statements:



set num_threads=8 ; number of physical core in your machine

set ngbehavior=hsa ; set compatibility for reading PDK libs

set skywaterpdk ; skip some checks for faster lib loading 

set ng_nomodcheck ; trust the models, don't check the model parameters          

unset interactive ; run scripts without interruption (default)

set nginfo ; some more info

option KLU ; select KLU solver over Sparse 1.3 solver



Run the simulation by calling

ngspice skywater_inverter.net



A plotting alternative in addition to the internal graphics is gnuplot.