LTspice IV is a fourth generation SPICE simulation program from Linear Technology. The program consists of a high performance SPICE simulator that greatly improves the simulation speed of circuits such as a Switch Mode Power Supply (SMPS) while maintaining accuracy. The program also contains an integrated schematic capture program, enabling users to create and edit circuits, plus an integrated waveform viewer to analyse simulation data. Included with LTspice IV is an extensive database of macromodels for Linear Technology's devices and many passive components. LTspice IV is node-unlimited and third party models can be imported easily.
Download LTspice IV from;
Linear Technology; www.linear.com/LTspice