• To design and complete layout of a cmos inverter using opensource vlsi tools and obtain various parameters of performance with graphs.

• setup shop in Windows Subsystems for Linux (WSL), [ubuntu will also work]

• xschem
• ngspice
• skywater pdk
• Magic

• open your terminal in an ubuntu device or wsl

  ### xschem ###
  git clone https://github.com/StefanSchippers/xschem.git xschem
  cd xschem
  ./configure
  sudo make -j4
  sudo make install
  cd ..
  
  ### NGSpice ### 
  git clone git://git.code.sf.net/p/ngspice/ngspiced
  cd ngspiced
  ./autogen.sh
  mkdir release
  cd release
  ../configure --with-x --enable-xspice --disable-debug --enable-cider --with-readline=yes --enable-predictor --enable-osdi --enable-openmp
  sudo make -j4
  sudo make install
  cd ../..
  
  ### magic vlsi ###
  git clone git://opencircuitdesign.com/magic
  cd magic
  ./configure
  sudo make
  sudo make install
  cd ..
  # dont use -j4 
  
  ### openPDK ###
  git clone git://opencircuitdesign.com/open_pdks
  cd open_pdks
  ./configure --enable-sky130-pdk --enable-sram-sky130
  sudo make -j4
  sudo make install
  sudo make veryclean
  cd ..
  # these steps will take a lot of time and occupy a lot of space, be patient.....
  
  ### xschem and skywater 130 integration ###
  mkdir test_xschem_sky130
  cd test_xschem_sky130
  cp /usr/local/share/pdk/sky130B/libs.tech/xschem/xschemrc .
  xschem

# setup xschem with skywater pdk 130 
mkdir test_nfet
cd test_nfet
cp /usr/local/share/pdk/sky130B/libs.tech/xschem/xschemrc .
xschem

• press Shift + i in xschem window to add new schematic.
• insert the nfet from the library
• 

To run xschem with skywater pdk

 mkdir directory_name
 cd directory_name
 cp /usr/local/share/pdk/sky130B/libs.tech/xschem/xschemrc .
 xschem

• input and output voltage plot
  • 
• propogation delay
  • time from 50% Vin to 50 % Vout
  • 
  • showing propogation delay has dependance on imput pulse
    • 
• Rise time and fall time
  • tr = t90 - t10
  • 
• load capacitiance decreases, circuit becomes faster

Visual representation of CMOS inverter.

Documentation of SKYWATER PDK.

magic  -rcfile /usr/local/share/pdk/sky130A/libs.tech/magic/sky130A.magicrc &

• zoom out : shift z
• zoom in : shift z

grid on
grid 50nm 50nm
snap user 50nm
box size 0 0
box position 0 0
paint 'material'
undo