SLiCAP: more than SYMBOLIC SPICE

What it is

• SLiCAP is an acronym for: S ymbolic Li near C ircuit A nalysis P rogram
• SliCAP is a tool for algorithm-based analog design automation
• SLiCAP is intended for setting up and solving design equations of electronic circuits
• SLiCAP is a an open source application written in Python
• SLiCAP is part of the tool set for teaching Structured Electronics Design at the Delft University of Technology

Why you should use it

• SLiCAP facilitates analog design automation and stepwise, hierachically-structured, analog design
• SLiCAP lets you relate circuit component and device geometry requirements to system performance requirements
• SLiCAP makes complex symbolic circuit analysis doable
• SLiCAP speeds up the circuit design process
• SLiCAP integrates documentation and design ("one-click" update of HTML or PDF design reports)
• SLiCAP facilitates design education and knowledge building

Features

• SLiCAP-compatible schematic capture program with LaTeX rendering of expressions, with cli export of netlist, svg image and pdf image
• Accepts SPICE-like netlists as input and provides netlist generation from, amongst others, Kicad and LTspice schematic files.
• Facilitates concurrent design and documentation
• Supports and facilitates structured analog design

Capabilities

• Conversion of hierarchically structured SPICE netlist into a mixed symbolic/numeric matrix equation
• Symbolic and numeric noise analysis
• Symbolic and numeric noise integration over frequency
• Symbolic and numeric determination of transfer functions and polynomial coefficients of transfer functions
• Symbolic and numeric inverse Laplace Transform
• Symbolic and numeric determination of network solutions
• Symbolic and numeric pole-zero analysis (symbolic pole-zero analysis for low-order systems only)
• Symbolic and numeric Routh array
• Order estimation of feedback circuits (numeric only)
• Root-locus analysis with an arbitrarily selected circuit parameter as root locus variable
• Symbolic and numeric DC and DC variance analysis for determination of budgets for resistor tolerances, offset, temperature effects, matching and tracking
• Symbolic and numeric derivation and solution of design equations for bandwidh, frequency response, noise, dc variance, and temperature stability

Installing SLiCAP from pypi

1. Enter:

   pip install slicap
   

Addidional software

SLiCAP can generate netlists from schematic files from:

• Kicad (all platforms, preferred!)
• LTspice (MSWindows: install LTspice on the system drive, Linux and MacOS: use MSwindows version and wine)
• gschem (MSWindows: install gschem and its netlister on the system drive, Linux and MacOS: use lepton-eda)
• lepton-eda (Linux and MacOS, MSWindows: use gSchem for windows)

Preferred for all platforms is to install or upgrade to the latest version of Kicad, and install Inkscape.

LaTeX rendering of expressions (optional)

The schematic editor can typeset component values, parameter/model definitions and design-data expressions with LaTeX. This is optional — there is a plain-text fallback — and requires a TeX distribution that provides pdflatex and dvisvgm:

• Linux: install TeX Live (texlive-latex-base + texlive-latex-extra, or texlive-full). On some distributions dvisvgm is a separate package (e.g. sudo apt install dvisvgm).
• MSWindows: install MiKTeX (bundles both pdflatex and dvisvgm).
• macOS: install MacTeX.

Ghostscript is NOT required. SLiCAP renders via DVI (pdflatex -> DVI -> dvisvgm), not via PDF, so the dvisvgm --pdf path that would need Ghostscript is never used.

The pdflatex and dvisvgm locations are detected on first run and stored in SLiCAP.ini; they can be edited there manually. LaTeX rendering is enabled per schematic in File -> Preferences; the checkbox is disabled when the tools are not found.

First Run

On the first run:

• SLiCAP searches for installed applications:

  • Kicad,
  • LTspice
  • NGspice
  • gSchem (MSWindows only)
  • lepton-eda (Linux and MacOS)

• SLiCAP creates a SLiCAP.ini file in the user home directory. This file contains initial setting and commands to start the above applications. It can be edited manually, and when deleted it will be recreated on the next run. Searching for applications on MSWindows may take a while!

On the first run of a project, SLiCAP creates a SLiCAP.ini file in the project folder, each time you run the project this file is updated. It will be recreated after deletion.

Documentation

>>> Help()

Opens HTML documentation in your default browser. It can also be viewed at https://slicap.org

Schematic editor command-line usage

The schematic editor can be launched from the command line with:

slicap

This opens the full schematic editor window. For a lighter startup without the instruction panel and related simulation dock widgets, use:

slicap-schematics

You can also open a schematic directly and let the program infer the schematic type from the file extension:

slicap mycircuit.slicap_sch
slicap mycircuit.spice_sch

If you want to force the mode explicitly, use --config:

slicap-schematics --config slicap mycircuit.slicap_sch
slicap-schematics --config ngspice mycircuit.spice_sch

The CLI also supports direct file export for schematic workflows:

python -m SLiCAP.schematic.cli netlist mycircuit.slicap_sch
python -m SLiCAP.schematic.cli svg mycircuit.slicap_sch
python -m SLiCAP.schematic.cli pdf mycircuit.slicap_sch

Setting up SLiCAP from source code

1. Install Python 3.12+ (for MSwindows Anaconda installation is preferred)

2. Download or clone the SLiCAP archive from github

3. Extract it in some directory

4. Open a terminal (or an Anaconda terminal if you run python from Anaconda) in the directory with pyproject.toml

5. Install:

   python -m pip install .
   

   Don't forget the dot! This also installs all required packages, listed in pyproject.toml.

6. Make Documentation:

   cd ./docs
   make html
   cd ..
   

Contributing

If you want to contribute to the development of SLiCAP, please Email Us.

Bugs

In case bugs are found, please report them to the 'Issues' page.