[6][7] It ships with a library of SPICE models from Analog Devices, Linear Technology, Maxim Integrated, and third-party sources.

[citation needed] It has enhancements and specialized models to speed the simulation of switched-mode power supplies (SMPS) in DC-to-DC converters.

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.

At any time, a user can manually update LTspice by choosing "Sync Release" from the "Tools" pulldown menu.

Over time, SPICE models for Analog Devices components have gradually been added to LTspice.

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).

[16] Starting with LTspice XVII, control panel settings were added to allow the user to specify search directories for 3rd party device symbols and libraries.

In LTspice, any suffix (left column) can replace the decimal point of a real number, a common format for printed schematics.

Although LTspice was originally based upon Berkeley SPICE 3f5 source code,[1] it no longer is, thus some of its features may create non-portable files.

[27] The two graphical symbols represent: Historically, SPICE and older version of LTspice software only supported printable ASCII characters for node/net names, then LTspice XVII added support for Unicode characters.

Two are automatically determined, while three others are chosen by the "Port Type" field in the "Label Net" wizard.

LTspice schematics are stored as an ASCII text file with a filename extension of "asc".

The bottom three TEXT lines are: 1) a transient simulation directive with a stop time parameter of 10 ms (.tran 10mS), 2) a SPICE directive to set the initial condition of RC "out" net to zero volts (.ic v(OUT)=0V), and 3) a text comment (title).

LTspice waveform viewer plot settings are stored as an ASCII text file with a filename extension of "plt".