Linear Technology has announced LTspice IV, a major update to its free SPICE circuit simulation software LTspice/SwitcherCADIII. LTspice IV features multi-threaded solvers designed to better utilize current multicore processors. Also included are new SPARSE matrix solvers that deploy assembly language in order to approach the theoretical flop limit of current FPUs (floating point units). LTspice IV speeds up the simulation speed of medium- to large-sized circuits by a factor of three on a quad core.
Parallel processing has been a long-standing challenge for SPICE simulators. LTspice IV implements proprietary methods that efficiently implement parallel tasks that would require as little as 5us to run single-threaded.
LTspice IV also includes integrated schematic capture and waveform viewing. While it has been associated with switch-mode power design (it ships with over 1000 models of switch-mode regulators and controllers), LTspice IV is not an SMPS-specific SPICE program but rather a general-purpose SPICE that includes new spice components so it is fast enough to interactively simulate SMPSs. LTspice IV is not artificially limited by component or node count.
Linear's LTspice IV can be freely downloaded at www.linear.com/designtools/software.