XVII / November 18, 2016
|Operating system||Windows, OS X|
|Type||Electronic design automation|
LTspice IV provides a schematic capture and waveform viewer with enhancements and models to speed the simulation of switching regulators. Supplied with LTspice IV are macro models for 80% of LTC's switching regulators and operational amplifiers, transistors, MOSFETs, and passive components.
LTspice IV is node-unlimited and third-party models can be imported. Circuit simulations based on transient, AC, noise and DC analysis can be plotted as well as Fourier analysis. Heat dissipation of components can be calculated and efficiency reports can also be generated.
LTspice IV is used within LTC, and by many users in fields including radio frequency electronics, power electronics, digital electronics, and other disciplines. LTspice IV does not generate printed circuit board (PCB) layouts, but netlists can be imported into layout programs. While LTspice does support simple logic gate simulation, it is not designed specifically for simulating logic circuits.
LTspice was originally called SwitcherCAD and is sometimes still called by that name. The software is maintained by Mike Engelhardt. The application is written for Microsoft Windows but, since 2003, it will run under the Wine Windows compatibility layer under Linux. Since 2013 there is also a native OS X version available, albeit with a crippled user interface that lacks essential features such as the command toolbar. From version IV LTspice requires at least a Pentium 4 processor and Windows 2000 or later.
In 2016 LTspice XVII was released. It runs on 32- or 64-bit editions of Windows 7, 8, and 10.
Many of the LTspice files are stored as an ASCII text file, which can be viewed or edited with any ASCII text editor programs. One of the side benefits of an ASCII file format is that a schematic can be listed in a printed document or book, which allows the reader to recreate LTspice files without electronic file distribution.
The following example shows the contents from a small LTspice schematic file for a simple RC circuit with 4 symbols: 10 volt voltage source, 1000 ohm resistor, 10 uF capacitor, ground symbol. The bottom two lines are a transient simulation directive with a stop time parameter of 10 mS (
.tran 0.01), and a SPICE directive to set the initial RC "output" condition to zero volts (
.ic v(output)=0). This schematic can be viewed by copying the text, pasting it into an ASCII text editor, saving it as file with the file extension of "asc", then opening the file with LTspice.
Version 4 SHEET 1 880 680 WIRE 224 96 128 96 WIRE 128 160 128 96 WIRE 224 192 224 176 WIRE 288 192 224 192 WIRE 224 208 224 192 WIRE 128 288 128 240 WIRE 224 288 224 272 WIRE 224 288 128 288 WIRE 224 304 224 288 FLAG 224 304 0 FLAG 288 192 output SYMBOL res 208 80 R0 SYMATTR InstName R1 SYMATTR Value 1000 SYMBOL cap 208 208 R0 SYMATTR InstName C1 SYMATTR Value 1µ SYMATTR SpiceLine V=50 SYMBOL voltage 128 144 R0 WINDOW 123 0 0 Left 0 WINDOW 39 0 0 Left 0 SYMATTR InstName V1 SYMATTR Value 10 TEXT 118 344 Left 2 !.tran 0.01 TEXT 120 376 Left 2 !.ic v(output)=0