From concept to prototype, eSim simplifies every step of the electronics design process in one intuitive environment.
eSim is a free and open-source Electronic Design Automation (EDA) tool developed by the FOSSEE team at IIT Bombay. It integrates multiple functionalities—circuit design, simulation, analysis, and PCB layout—into a single platform. Built upon open-source software like KiCad, Ngspice, GHDL, OpenModelica, Verilator, Makerchip, and the SkyWater SKY130 PDK, eSim offers a comprehensive solution for electronic design tasks. This integration allows engineers, educators, and hobbyists to perform schematic capture, simulate circuits (analog, digital, and mixed-signal), and design PCBs without the need for multiple proprietary tools.
Key Features of eSim
- Integrated Schematic Capture and PCB Layout: Utilizes KiCad’s Eeschema and CvPcb for creating schematics and designing multi-layered PCBs.
- Analog and Digital Simulation: Incorporates Ngspice for analog simulations and GHDL and Verilog for digital simulations, supporting mixed-signal analysis.
- Model and Subcircuit Management: Provides Model Builder and Subcircuit Builder tools for adding or editing SPICE models and subcircuits.
- OpenModelica Integration: Enables system-level modeling and simulation of complex multi-domain systems.
- Makerchip Support: Facilitates digital design and simulation using the Makerchip platform.
- SkyWater SKY130 PDK Support: Allows for open-source semiconductor process design kit usage.
- Cross-Platform Compatibility: Supports Linux and Windows operating systems.
- Python Integration: Offers scripting capabilities for automation and customization.
The latest release in March 2025, eSim 2.5, brings a host of improvements designed to make electronic design more streamlined and efficient. One of the most notable additions is the modular installation feature, which allows users to install only the components they need, reducing setup complexity and conserving system resources. As one user noted, “The latest version’s modular installation is a welcome change. It makes setting up the environment much simpler.”
The user interface has also received significant updates, making it more intuitive and smoother to navigate, which helps accelerate the design and simulation workflow. Alongside this, the simulation capabilities have been enhanced, with support for additional models and improved accuracy in results, enabling more precise circuit analysis. Designers have praised these improvements, with one commenting, “eSim has been a game-changer for my students. It’s intuitive and covers all aspects of circuit design and simulation.”
In addition, it includes updated component libraries, expanding design possibilities for engineers and hobbyists alike. The tool also introduces an AI-powered chatbot to assist with debugging and troubleshooting, while the tool tracker ensures seamless support and issue resolution. Other updates include a better installer with Docker support, enhanced plotting features for visualization, UI refinements, and fixes for several stability-related bugs. These updates collectively make eSim 2.5 a more powerful and user-friendly EDA solution.
eSim remains completely free and open-source under the GNU General Public License, making it accessible to educational institutions, startups, and individual engineers. The free version provides all core functionalities, allowing users to perform comprehensive circuit design, simulation, and PCB layout without any cost. The open-source nature also encourages users to modify and extend the tool according to their needs, promoting innovation and community-driven development. As one electronics designer put it, “I appreciate the open-source nature of eSim. It’s a robust alternative to expensive proprietary tools.”
For more information and to download eSim, click here.
