I use Linear Technology's SwitcherCAD III, which is totally free, fully functional (not castrated like some demo or student versions), has a good schematic editor, and includes models of LTC's parts (and you can add your own or those from vendors).
I use Linear Technology's SwitcherCAD III, which is totally free, fully functional (not castrated like some demo or student versions), has a good schematic editor, and includes models of LTC's parts (and you can add your own or those from vendors).