http://www.electronics-lab.com/download/sg3524-proteus-library/
Below is the resource containing the SG3524 library files and project examples. sg3524 proteus library download link
You can create a custom Proteus component and attach a SPICE .lib or .mod file to it. A heavily referenced Russian electronics repository by Valvolodin hosts a library pack containing the SPICE model for the 3524; you can find it directly in this Archived Edaboard Thread . http://www
If you repeatedly fail to find a working library, consider simulating SG3524 circuits online. These platforms have the IC built-in: sg3524 proteus library download link