SIMetrix/SIMPLIS 5.60.0.5151 could be downloaded from the developer's website when we last checked. We cannot confirm if there is a free download of this software available.
We cannot guarantee that the program is safe to download as it will be downloaded from the developer's website. Before launching the program, check it with any free antivirus software. This tool was originally developed by Catena Software Ltd. The program is included in Photo & Graphics Tools.
From the developer:
SIMetrix/SIMPLIS enables engineers to design and simulate switching power electronics systems. It combines accuracy and speed in a full-featured design environment, enabling 10-50x faster simulation than SPICE for power supply designs.
You may want to check out more software, such as SIMetrix-SIMPLIS Elements, which might be similar to SIMetrix/SIMPLIS.