If you place the LM2596 and get a "No Model Specified" error, you have the schematic symbol but not the simulation file. Ensure you have downloaded a model file that supports , specifically looking for files named LM2596.MOD or LM2596.CIR .
Connections: Pin1 (VIN) → +12V + 330µF cap Pin2 (OUT) → 100µH → 220µF + load Pin3 (GND) → Common ground Pin4 (FB) → Voltage divider (1k & 3.3k) Pin5 (ON/OFF) → GND (enable) Diode: 1N5822 from Pin2 to GND lm2596 library for proteus top