SpiceRack

Build SPICE circuits in Python, run them on the simulator you have, and get the results back as Python lists. One circuit description emits ngspice, LTspice, VACASK, Spectre, ESPice and HSPICE decks.

Install

pip install fast-spicerack       # imported as `spicerack`

You also need a simulator on $PATH to run anything. Start with ngspice. Without one, SpiceRack still writes netlists.

Tool	What it adds
ngspice	The default backend; the only one with XSPICE, control blocks and digital Verilog
vacask, spectre, ltspice, espice	Other backends
openvaf	Verilog-A models on ngspice, VACASK and Spectre
iverilog, yosys	Digital Verilog: co-simulation, or synthesis to gates

From source: pip install maturin && maturin develop in a clone (needs Rust). With Nix, nix develop .#testing gives the build tools plus ngspice, OpenVAF, VACASK and the sky130/gf180 PDKs.

Quick start

A voltage divider, solved for its operating point:

import spicerack as ps

dut = ps.Subcircuit("divider", ["vin", "vout"])
dut.R("top", "vin", "vout", 2e3)
dut.R("bot", "vout", dut.gnd, 1e3)

tb = ps.Testbench(dut)
tb.V("supply", "vin", "0", 9.0)

print(tb.netlist("ngspice"))           # the deck, no simulator needed
print(tb.operating_point()["vout"])     # 3.0

An RC low-pass, swept in frequency:

rc = ps.Subcircuit("rc", ["vin", "vout"])
rc.R("1", "vin", "vout", 1e3)
rc.C("1", "vout", rc.gnd, 1e-6)

tb = ps.Testbench(rc)
tb.V("in", "vin", "0", 0.0, ac=1.0)
ac = tb.ac(variation="dec", number_of_points=50, start_frequency=1, stop_frequency=1e5)

gain_db = ac.magnitude_db("vout")       # list[float], one per ac.frequency point

What is in here

Page	Covers
Circuits	Circuit, Subcircuit, Testbench, every element and source, units, models, saving to JSON
Simulating	Analyses, reading results, simulator options, choosing a backend, linting
Models and PDKs	Model libraries and corners, Verilog-A, digital Verilog
Testbenches	About 60 ready-made benches (amplifiers, regulators, converters, PLLs...), corners and Monte Carlo
Re-measuring	Recomputing SNDR, settling, margins, noise and yield from a .raw file
Tools	The spice2rack converter, the Rust crate, the JSON circuit format
API reference	Every class, method and signature on one page

The examples/ folder has 22 runnable scripts, from a voltage divider to the testbench library.

SpiceRack is pre-1.0: pin a version, since the API can change between minor releases. MIT licensed.