LTspice is a SPICE-based analog electronic circuit simulator computer software, produced by semiconductor manufacturer Analog Devices (originally by Linear Technology). It is the most widely distributed and used SPICE software in the industry. Though it is freeware, LTspice is not artificially restricted to limit its capabilities (no feature limits, no node limits, no component limits, no subcircuit limits). It ships with a library of SPICE models from Analog Devices, Linear Technology, Maxim Integrated, and third-party sources.
Overview
LTspice provides schematic capture to enter an electronic schematic for an electronic circuit, an enhanced SPICE type analog electronic circuit simulator, and a waveform viewer to show the results of the simulation. Circuit simulation analysis based on transient, noise, AC, DC, DC transfer function, DC operating point can be performed and plotted as well as fourier analysis. Heat dissipation of components can be calculated and efficiency reports can also be generated. It has enhancements and specialized models to speed the simulation of switched-mode power supplies (SMPS) in DC-to-DC converters.
LTspice does not generate printed circuit board (PCB) layouts, but netlists can be exported to PCB layout software. While LTspice does support simple logic gate simulation, it is not designed specifically for simulating logic circuits.
It is used by many users in fields including radio frequency electronics, power electronics, audio electronics, digital electronics, and other disciplines.
LTspice/SwitcherCAD III
In 1999, LTspice III was released, the first public release. It is designed to run on Windows 95, 98, 98SE, ME, NT4.0, 2K, XP. This version is no longer available for download from Analog Devices. Initially, LTspice III was internally released to Linear Technology's Field Application Engineers (FAE) in October 1999, who then gave it away during customer visits via CD-ROM media. In June 2001, it was released for public downloading from the Linear Technology website. Originally, LTspice/SwitcherCAD ran only on Microsoft Windows platforms, but since 2003 it is able to run under the Wine Windows compatibility layer on Linux.
LTspice IV
In 2008, LTspice IV was released. It is designed to run on Windows 2K, XP, Vista, 7 with a processor that contains a minimum instruction set similar to a Pentium 4 processor. Though IV is still available for download, it is no longer maintained. LTspice was originally called SwitcherCAD, but that name was removed when IV was released. A native Apple macOS 10.7+ application was introduced in 2013.
LTspice XVII
In 2016, LTspice XVII was released, and is currently the latest version. It is designed to run on 32-bit or 64-bit editions of Windows 7, 8, 8.1, 10, and macOS 10.9+.
Summary of major changes from LTspice IV to LTspice XVII are: Add 64-bit executables. Add Unicode characters in schematics, netlists, plot. Add device equations for IGBT, diode soft recovery, arbitrary state machine. Add user-defined symbol and library directory search path settings to the LTspice control panel. Add schematic thumbnail and preview support on Microsoft Windows. Add editors for most SPICE commands. Add multi-monitor support.
Updates
Every month, LTspice updates have been released with new SPICE models, fixed SPICE models, or software changes. At any time, a user can manually update LTspice by choosing "Sync Release" from the "Tools" pulldown menu. From the "Help" pulldown menu, "Show Change Log" displays a list of every SPICE model and software change since LTspice XVII was first released.
In March 2017, Linear Technology merged into Analog Devices. Over time, SPICE models for Analog Devices components have gradually been added to LTspice.
In August 2021, Maxim Integrated merged with Analog Devices. Since then, SPICE models for Maxim components are being gradually added into LTspice.
Updates are no longer provided for Windows XP and MacOS 10.9, as well as older versions of Windows and MacOS.
Device models
LTspice ships with thousands of third-party models (capacitors, diodes, inductors, resistors, transistors, ferrite beads, opto-isolators, 555 timer, and more), as well as macro models for Analog Devices and Linear Technology parts (ADCs, analog switches, comparators, DACs, filters, opamps, timers, voltage references, voltage supervisors, voltage regulators, 0.01% quad resistor networks, and more). In the device library, Analog Devices part numbers start with "AD", and Linear Technology parts start with "LT".