SpiceSharpParser

SpiceSharpParser parses SPICE netlists and translates them into ordinary SpiceSharp circuits and simulations. It supports broad SPICE, PSpice, and LTspice syntax for .NET Standard 2.0 and .NET 8.0.

Current release: 3.4.1 is a hardening-only release for experimental LTspice A-device integration. It adds fixes and regression coverage without adding new A-device families.

For the complete feature and API reference, see the detailed project guide.

Highlights

• Parse .AC, .DC, .TRAN, .OP, and .NOISE analyses.
• Translate netlists into normal SpiceSharp circuits and simulation objects.
• Load recursive .INCLUDE/.LIB dependencies with source-located diagnostics.
• Use .SAVE, .PRINT, .PLOT, .MEAS, and .FOUR results from the netlist.
• Load reusable .SUBCKT libraries into programmatically assembled circuits.
• Opt into LTspice A-devices, ideal diodes, nonlinear passives, digital logic, analog functional models, and a functional 555 with the companion package.

Installation

Install the core parser:

dotnet add package SpiceSharp-Parser

Install the optional models only when they are needed:

dotnet add package SpiceSharpParser.CustomComponents

Requirement	Package
Parse and simulate ordinary SPICE netlists	SpiceSharp-Parser
Load user-authored .SUBCKT libraries	SpiceSharp-Parser
Parse supported LTspice A-devices and ideal/nonlinear devices	SpiceSharpParser.CustomComponents
Use packaged digital, analog, and functional 555 models	SpiceSharpParser.CustomComponents

See the CustomComponents README for setup, model explanations, examples, and compatibility limits.

Quick Start

The original API exposes parsing, translation, and simulation as separate steps:

using System;
using System.Linq;
using SpiceSharpParser;
using SpiceSharpParser.Common;

var netlist = string.Join(Environment.NewLine,
    "Low-pass RC filter",
    "V1 IN 0 AC 1",
    "R1 IN OUT 1k",
    "C1 OUT 0 1u",
    ".AC DEC 10 1 1MEG",
    ".SAVE V(OUT)",
    ".END");

// Parse the SPICE text.
var parser = new SpiceNetlistParser();
var parsed = parser.ParseNetlist(netlist);

// Translate it into SpiceSharp objects.
var reader = new SpiceSharpReader();
var model = reader.Read(parsed.FinalModel);

// Run the analysis and read the requested export.
var simulation = model.Simulations.Single();
var output = model.Exports.Find(export => export.Name == "V(OUT)");
simulation.EventExportData += (_, _) => Console.WriteLine(output.Extract());
simulation.Execute(model.Circuit);

Choose an API

Goal	API
Direct control over an in-memory netlist	SpiceNetlistParser, then SpiceSharpReader
Compile user or vendor files with stable diagnostics	SpiceCompiler.CompileFile(...)
Load selected .SUBCKT definitions into a circuit	SpiceSubcircuitLibrary.LoadFile(...) or LoadText(...)
Enable optional netlist components in the original API	reader.Settings.UseCustomComponents() before Read()
Enable optional components with SpiceCompiler	SpiceCompileOptions.ConfigureReader

SpiceCompiler adds recursive dependency loading, recovery, compatibility classification, structural linting, and JSON/SARIF diagnostic output. See the detailed project guide and diagnostic reference.

Optional LTspice A-devices

SpiceSharpParser.CustomComponents supports these native eight-terminal A-device families:

Digital	Analog and mixed-signal
SRFLOP, DFLOP, PHASEDET, COUNTER	SAMPLEHOLD, OTA, VARISTOR, MODULATOR/MODULATE

Terminal 8 is common. A terminal is unused only when it repeats that common node; if common is not ground, a literal 0 remains an active global-ground connection. Unused outputs are detached, and an unused MODULATOR amplitude input selects the native amplitude of 1.

Complete netlists, .SAVE/.PLOT waveforms, .MEAS checks, and guides are in the runnable A-device example pack.

Circuit Cookbook

The Circuit Cookbook turns parser features into complete, practical designs. Every recipe includes a runnable netlist, named measurements, design calculations, an accessible generated schematic, a response summary, suggested experiments, and automated regression coverage.

Difficulty	Circuit	Main lesson
Simple	PWM digital-to-analog converter	Duty-cycle averaging, ripple attenuation, and settling
Simple	RC sensor filter and input protector	Sensor bandwidth, noise attenuation, rail clamping, and fault current
Simple	BJT relay driver	Inductive-load switching, saturation, flyback, and release decay
Simple	Loaded voltage divider and emitter-follower buffer	Source loading, Thevenin resistance, transistor buffering, and output impedance
Simple	Diode peak detector and AM envelope follower	Diode-drop error, RC attack/release, carrier ripple, and envelope recovery
Simple	Two-transistor astable LED flasher	Cross-coupled feedback, RC timing, transistor switching, and free-running oscillation
Medium	Rectifier power supply	Rectification, reservoir ripple, Zener regulation, and load response
Medium	BJT audio preamplifier	Biasing, AC gain, bandwidth, coupling, loading, and distortion
Medium	Active anti-alias filter	Buffered poles, stopband attenuation, settling, and ADC loading
Medium	Ideal-diode redundant power input	Supply OR-ing, automatic failover, handback, and reverse-current blocking
Difficult	Simple phase-locked loop	Phase detection, loop filtering, voltage-controlled oscillation, and lock behavior
Difficult	Transmission-line termination	Propagation delay, reflections, ringing, and impedance matching

Cookbook schematics are generated from reviewable schematic.toml files with the repository-local SchemDraw renderer. The cookbook report verifies recipe structure, netlist/layout consistency, SVG accessibility, and generated-asset freshness:

.\tools\cookbook-schematic\.venv\Scripts\cookbook-report

Run the simulation and measurement regressions separately:

dotnet test src/SpiceSharpParser.Tests/SpiceSharpParser.Tests.csproj `
  --filter 'FullyQualifiedName~CircuitCookbookTests'

Documentation

The former long README reference is split across these focused documents:

Topic	Document
Full project reference	Detailed Project Guide
Practical, measured designs	Circuit Cookbook
Documentation by statement and device	Documentation Index
Parser introduction	Introduction
Compiler diagnostics	Diagnostic Reference
LTspice compatibility status	Compatibility Matrix
Programmatic subcircuit libraries	Subcircuit Library Guide
LTspice A-devices	A-device Guide
Digital logic and functional 555	Digital Subcircuits
Analog special functions	Analog Subcircuits
LTspice-style ideal diode	Ideal Diode
Nonlinear capacitors and inductors	Nonlinear Passives
Measurements and output	.MEAS, .PRINT, .PLOT

Build from Source

git clone https://github.com/SpiceSharp/SpiceSharpParser.git
cd SpiceSharpParser

dotnet restore src/SpiceSharp-Parser.sln
dotnet build src/SpiceSharp-Parser.sln
dotnet test src/SpiceSharpParser.Tests/SpiceSharpParser.Tests.csproj
dotnet test src/SpiceSharpParser.IntegrationTests/SpiceSharpParser.IntegrationTests.csproj

License

SpiceSharpParser is licensed under the MIT License.