Electronics Design Automation - KiCad SPICE Modeling

BME254L - Spring 2026

Dr. Mark Palmeri, M.D., Ph.D.

Duke University

January 8, 2026

Electronics Design Automation: SPICE Modeling

What is SPICE?

  • Simulation Program with Integrated Circuit Emphasis (SPICE)

  • Model and analyze the behavior of electronic circuits before they are physically constructed.

  • Input schematic representations of circuits (e.g., resistors, capacitors, transistors, diodes, etc.)

  • Simulate circuit performance by computing current, voltage, and power, across these components under different conditions.

Why model circuits?

  • Reduce design costs.

  • Breadboards / thru-hole prototyping is not realistic for complex circuits.

  • Most components are now surface mount.

  • Model \(\rightarrow\) Breakout Boards \(\rightarrow\) PCB

SPICE vs. Non-SPICE Components

  • SPICE components are defined by their mathematical models.

  • Non-SPICE components are defined by their physical characteristics.

  • KiCad has a library of SPICE models for common components.

  • SPICE models are not always available for all components, but can be downloaded and added to some libraries.

  • SPICE models can be edited / created for custom components.

Limiting Scope of SPICE Simulation

  • We usually want to simulate as simple of a circuit as possible.

  • We can limit the scope of the simulation by excluding components from the braoder schematic from the sub-circuit that we want to simulate:

    1. Drag select all of the components you want to exclude to highlight them.

    2. Right Click: Attributes -> Exclude from Simulation

    3. Repeat this for other sheets / circuits in the schematic.

    4. In the Simulation window, Confirm that your SPICE Netlist reflets what you actually want to simulate.

Setting Component Simulation Parameters

  • The SPICE model can be set in the component properties.

  • The component must have a SPICE model to be included in the simulation.

  • Only certain components allow certain simulation parameters to be varied (e.g., resistors vs. potentiometers).

Setting Analysis Parameters

  1. AC Sweep: frequency analysis

  2. DC Sweep: sweep voltage, current, resistance, capacitance

  3. Operating Point: analysis at a specific point in time

  4. Transient: time-domain analysis

Run Simulation and Probe Components

  • Simulations are Run (Blue Arrow in Simulation window).

  • Probes can be added by parameter and component name or interactively.

  • Choose a New Analysis and what components you want to sweep.

    • Avoid setting any values to 0 as they can cause numerical instability!

  • After you hit Ok, choose the parameters from the right side of the window that you would like to plot.

  • If you change your schematic, be sure to re-Run the simulation.

    • You may want to create a new analysis tab to make sure that the simulation reflects the latest changes.

  • All open analysis tabs must be valid for the running simulation to be successful!

Examples

Resources