Electronic – What are the freeware SPICE simulators available


Does anyone know of a freeware SPICE / circuit simulator?

SPICE (Simulation Program with Integrated Circuit Emphasis) is a general-purpose, open source analog electronic circuit simulator. It is a powerful program that is used in integrated circuit and board-level design to check the integrity of circuit designs and to predict circuit behavior. Wikipedia

Best Answer

  • ngSpice is available for gEDA.
  • gnuCAP is also available for gEDA.
  • LTSpice is free from Linear Technology.

I thought that one of the other analog chip makers had a spice too but I can't remember who :(

I have been to a few talks on simulation given by physicists and EEs who have done chip design. Each of the talks seems to end like this ---

  • Except for simple circuits you will spend most of your time getting models and determining where the models need to be modified for your application.
  • Unless you are doing work for an IC manufacturer the manufacturer will not give you detailed models.
  • You will not be able to avoid a prototype.
  • You should only simulate subsections of your design. Simulating the entire design is not usually practical.

Also most of the free simulators are not distributed with models. Re-distribution of the models is usually a copyright violation. LTspice is distributed with models of the Linear Tech parts. I am not sure the quality of the models. Most manufacturers do not want to reveal too many details about their process.