LTspice IV is a high performance SPICE simulator, schematic capture and waveform viewer with enhancements and models for easing the simulation of switching regulators. Our enhancements to SPICE have made simulating switching regulators extremely fast compared to normal SPICE simulators, allowing the user to view waveforms for most switching regulators in just a few minutes.
Included in this download are LTspice IV, Macro Models for 80% of Linear Technology's switching regulators, over 200 op amp models, as well as resistors, transistors and MOSFET models. Capacitors and inductors can be modeled with series resistance and other parasitic aspects of their behavior without using sub-circuits or internal nodes.
DOWNLOAD LTspice IV - 4.21t / Windows For Free