When searching for a library, look for the because it is the most versatile. If you find a library for the fixed versions, ensure the pinout matches (the feedback pin is usually grounded or tied to output internally).
Place the model in Proteus subdirectory
: Close and reopen the software to refresh the database. You can then search for "LM2596" in the "Pick Devices" (P) menu. Simulation and Usage lm2596 library for proteus