<s>
LTspice	B-Algorithm
is	O
a	O
SPICE-based	O
analog	O
electronic	B-Language
circuit	I-Language
simulator	I-Language
computer	O
software	O
,	O
produced	O
by	O
semiconductor	O
manufacturer	O
Analog	O
Devices	O
(	O
originally	O
by	O
Linear	O
Technology	O
)	O
.	O
</s>
<s>
It	O
is	O
the	O
most	O
widely	O
distributed	O
and	O
used	O
SPICE	B-Protocol
software	O
in	O
the	O
industry	O
.	O
</s>
<s>
Though	O
it	O
is	O
freeware	B-License
,	O
LTspice	B-Algorithm
is	O
not	O
artificially	O
restricted	O
to	O
limit	O
its	O
capabilities	O
(	O
no	O
feature	O
limits	O
,	O
no	O
node	O
limits	O
,	O
no	O
component	O
limits	O
,	O
no	O
subcircuit	O
limits	O
)	O
.	O
</s>
<s>
It	O
ships	O
with	O
a	O
library	O
of	O
SPICE	B-Protocol
models	O
from	O
Analog	O
Devices	O
,	O
Linear	O
Technology	O
,	O
Maxim	O
Integrated	O
,	O
and	O
third-party	O
sources	O
.	O
</s>
<s>
LTspice	B-Algorithm
provides	O
schematic	B-Application
capture	O
to	O
enter	O
an	O
electronic	B-Application
schematic	I-Application
for	O
an	O
electronic	O
circuit	O
,	O
an	O
enhanced	O
SPICE	B-Protocol
type	O
analog	O
electronic	B-Language
circuit	I-Language
simulator	I-Language
,	O
and	O
a	O
waveform	O
viewer	O
to	O
show	O
the	O
results	O
of	O
the	O
simulation	O
.	O
</s>
<s>
Circuit	B-Language
simulation	I-Language
analysis	O
based	O
on	O
transient	O
,	O
noise	O
,	O
AC	O
,	O
DC	O
,	O
DC	O
transfer	O
function	O
,	O
DC	O
operating	O
point	O
can	O
be	O
performed	O
and	O
plotted	O
as	O
well	O
as	O
fourier	O
analysis	O
.	O
</s>
<s>
LTspice	B-Algorithm
does	O
not	O
generate	O
printed	O
circuit	O
board	O
(	O
PCB	O
)	O
layouts	O
,	O
but	O
netlists	O
can	O
be	O
exported	O
to	O
PCB	O
layout	O
software	O
.	O
</s>
<s>
While	O
LTspice	B-Algorithm
does	O
support	O
simple	O
logic	O
gate	O
simulation	O
,	O
it	O
is	O
not	O
designed	O
specifically	O
for	O
simulating	O
logic	O
circuits	O
.	O
</s>
<s>
In	O
1999	O
,	O
LTspice	B-Algorithm
III	O
was	O
released	O
,	O
the	O
first	O
public	O
release	O
.	O
</s>
<s>
It	O
is	O
designed	O
to	O
run	O
on	O
Windows	B-Application
95	O
,	O
98	O
,	O
98SE	O
,	O
ME	O
,	O
NT4.0	O
,	O
2K	O
,	O
XP	O
.	O
</s>
<s>
Initially	O
,	O
LTspice	B-Algorithm
III	O
was	O
internally	O
released	O
to	O
Linear	O
Technology	O
's	O
Field	O
Application	O
Engineers	O
(	O
FAE	O
)	O
in	O
October	O
1999	O
,	O
who	O
then	O
gave	O
it	O
away	O
during	O
customer	O
visits	O
via	O
CD-ROM	B-Device
media	O
.	O
</s>
<s>
Originally	O
,	O
LTspice/SwitcherCAD	O
ran	O
only	O
on	O
Microsoft	B-Application
Windows	I-Application
platforms	O
,	O
but	O
since	O
2003	O
it	O
is	O
able	O
to	O
run	O
under	O
the	O
Wine	B-Application
Windows	B-Application
compatibility	O
layer	O
on	O
Linux	B-Application
.	O
</s>
<s>
In	O
2008	O
,	O
LTspice	B-Algorithm
IV	O
was	O
released	O
.	O
</s>
<s>
It	O
is	O
designed	O
to	O
run	O
on	O
Windows	B-Application
2K	O
,	O
XP	O
,	O
Vista	O
,	O
7	O
with	O
a	O
processor	O
that	O
contains	O
a	O
minimum	O
instruction	O
set	O
similar	O
to	O
a	O
Pentium	B-General_Concept
4	I-General_Concept
processor	O
.	O
</s>
<s>
LTspice	B-Algorithm
was	O
originally	O
called	O
SwitcherCAD	B-Algorithm
,	O
but	O
that	O
name	O
was	O
removed	O
when	O
IV	O
was	O
released	O
.	O
</s>
<s>
A	O
native	O
Apple	O
macOS	B-Application
10.7	O
+	O
application	O
was	O
introduced	O
in	O
2013	O
.	O
</s>
<s>
In	O
2016	O
,	O
LTspice	B-Algorithm
XVII	O
was	O
released	O
,	O
and	O
is	O
currently	O
the	O
latest	O
version	O
.	O
</s>
<s>
It	O
is	O
designed	O
to	O
run	O
on	O
32-bit	O
or	O
64-bit	O
editions	O
of	O
Windows	B-Application
7	O
,	O
8	O
,	O
8.1	O
,	O
10	O
,	O
and	O
macOS	B-Application
10.9	O
+	O
.	O
</s>
<s>
Summary	O
of	O
major	O
changes	O
from	O
LTspice	B-Algorithm
IV	O
to	O
LTspice	B-Algorithm
XVII	O
are	O
:	O
</s>
<s>
Add	O
Unicode	O
characters	O
in	O
schematics	B-Application
,	O
netlists	O
,	O
plot	B-Application
.	O
</s>
<s>
Add	O
device	O
equations	O
for	O
IGBT	O
,	O
diode	O
soft	O
recovery	O
,	O
arbitrary	O
state	B-Architecture
machine	I-Architecture
.	O
</s>
<s>
Add	O
user-defined	O
symbol	O
and	O
library	O
directory	O
search	O
path	O
settings	O
to	O
the	O
LTspice	B-Algorithm
control	O
panel	O
.	O
</s>
<s>
Add	O
schematic	B-Application
thumbnail	O
and	O
preview	O
support	O
on	O
Microsoft	B-Application
Windows	I-Application
.	O
</s>
<s>
Add	O
editors	O
for	O
most	O
SPICE	B-Protocol
commands	O
.	O
</s>
<s>
Add	O
multi-monitor	B-General_Concept
support	O
.	O
</s>
<s>
Every	O
month	O
,	O
LTspice	B-Algorithm
updates	O
have	O
been	O
released	O
with	O
new	O
SPICE	B-Protocol
models	O
,	O
fixed	O
SPICE	B-Protocol
models	O
,	O
or	O
software	O
changes	O
.	O
</s>
<s>
At	O
any	O
time	O
,	O
a	O
user	O
can	O
manually	O
update	O
LTspice	B-Algorithm
by	O
choosing	O
"	O
Sync	O
Release	O
"	O
from	O
the	O
"	O
Tools	O
"	O
pulldown	O
menu	O
.	O
</s>
<s>
From	O
the	O
"	O
Help	O
"	O
pulldown	O
menu	O
,	O
"	O
Show	O
Change	O
Log	O
"	O
displays	O
a	O
list	O
of	O
every	O
SPICE	B-Protocol
model	O
and	O
software	O
change	O
since	O
LTspice	B-Algorithm
XVII	O
was	O
first	O
released	O
.	O
</s>
<s>
Over	O
time	O
,	O
SPICE	B-Protocol
models	O
for	O
Analog	O
Devices	O
components	O
have	O
gradually	O
been	O
added	O
to	O
LTspice	B-Algorithm
.	O
</s>
<s>
Since	O
then	O
,	O
SPICE	B-Protocol
models	O
for	O
Maxim	O
components	O
are	O
being	O
gradually	O
added	O
into	O
LTspice	B-Algorithm
.	O
</s>
<s>
Updates	O
are	O
no	O
longer	O
provided	O
for	O
Windows	B-Application
XP	O
and	O
MacOS	B-Application
10.9	O
,	O
as	O
well	O
as	O
older	O
versions	O
of	O
Windows	B-Application
and	O
MacOS	B-Application
.	O
</s>
<s>
LTspice	B-Algorithm
ships	O
with	O
thousands	O
of	O
third-party	O
models	O
(	O
capacitors	O
,	O
diodes	O
,	O
inductors	O
,	O
resistors	O
,	O
transistors	B-Application
,	O
ferrite	O
beads	O
,	O
opto-isolators	O
,	O
555	O
timer	O
,	O
and	O
more	O
)	O
,	O
as	O
well	O
as	O
macro	O
models	O
for	O
Analog	O
Devices	O
and	O
Linear	O
Technology	O
parts	O
(	O
ADCs	O
,	O
analog	O
switches	O
,	O
comparators	O
,	O
DACs	O
,	O
filters	O
,	O
opamps	O
,	O
timers	O
,	O
voltage	O
references	O
,	O
voltage	O
supervisors	O
,	O
voltage	O
regulators	O
,	O
0.01	O
%	O
quad	O
resistor	O
networks	O
,	O
and	O
more	O
)	O
.	O
</s>
<s>
LTspice	B-Algorithm
allows	O
a	O
user	O
to	O
choose	O
from	O
device	O
models	O
that	O
ship	O
with	O
LTspice	B-Algorithm
,	O
as	O
well	O
as	O
allows	O
the	O
user	O
to	O
define	O
their	O
own	O
device	O
model	O
,	O
or	O
use	O
3rd	O
party	O
models	O
from	O
numerous	O
electronic	O
component	O
manufacturers	O
,	O
or	O
use	O
a	O
model	O
from	O
a	O
3rd	O
party	O
device	O
library	O
.	O
</s>
<s>
Starting	O
with	O
LTspice	B-Algorithm
XVII	O
,	O
control	O
panel	O
settings	O
were	O
added	O
to	O
allow	O
the	O
user	O
to	O
specify	O
search	O
directories	O
for	O
3rd	O
party	O
device	O
symbols	O
and	O
libraries	O
.	O
</s>
<s>
See	O
option	O
setting	O
at	O
LTspice	B-Algorithm
->	O
Tools	O
->	O
Control	O
Panel	O
->	O
Sym	O
.	O
</s>
<s>
The	O
text	O
that	O
describes	O
intrinsic	O
SPICE	B-Protocol
models	O
can	O
be	O
placed	O
directly	O
on	O
an	O
LTspice	B-Algorithm
schematic	B-Application
by	O
using	O
the	O
spice	B-Protocol
directive	O
.op	O
button	O
.	O
</s>
<s>
The	O
advantage	O
of	O
this	O
method	O
is	O
the	O
3rd	O
party	O
model	O
is	O
self-contained	O
as	O
part	O
of	O
the	O
schematic	B-Application
when	O
you	O
distribute	O
the	O
schematic	B-Application
file	O
.	O
</s>
<s>
The	O
same	O
.model	O
can	O
also	O
be	O
copied	O
to	O
an	O
ASCII	B-Protocol
text	I-Protocol
file	I-Protocol
on	O
your	O
computer	O
too	O
,	O
but	O
it	O
wo	O
n't	O
"	O
travel	O
"	O
with	O
a	O
schematic	B-Application
when	O
you	O
copy	O
it	O
to	O
another	O
computer	O
.	O
</s>
<s>
For	O
example	O
,	O
the	O
following	O
diode	O
part	O
numbers	O
are	O
n't	O
included	O
in	O
the	O
current	O
LTspice	B-Algorithm
device	O
library	O
:	O
</s>
<s>
In	O
LTspice	B-Algorithm
,	O
numeric	O
values	O
can	O
be	O
expressed	O
in	O
four	O
different	O
ways	O
:	O
integer	O
(	O
i.e.	O
</s>
<s>
In	O
LTspice	B-Algorithm
,	O
any	O
suffix	O
(	O
left	O
column	O
)	O
can	O
replace	O
the	O
decimal	O
point	O
of	O
a	O
real	O
number	O
,	O
a	O
common	O
format	O
for	O
printed	O
schematics	B-Application
.	O
</s>
<s>
Although	O
LTspice	B-Algorithm
was	O
originally	O
based	O
upon	O
Berkeley	O
SPICE	B-Protocol
3f5	O
source	O
code	O
,	O
it	O
no	O
longer	O
is	O
,	O
thus	O
some	O
of	O
its	O
features	O
may	O
create	O
non-portable	O
files	O
.	O
</s>
<s>
Competitor	O
SPICE	B-Protocol
programs	O
have	O
non-portable	O
features	O
too	O
.	O
</s>
<s>
LTspice	B-Algorithm
features	O
that	O
may	O
not	O
be	O
supported	O
by	O
some	O
SPICE	B-Protocol
programs	O
:	O
</s>
<s>
Unicode	O
characters	O
in	O
schematics	B-Application
,	O
netlists	O
,	O
plot	B-Application
.	O
</s>
<s>
This	O
is	O
a	O
new	O
feature	O
in	O
LTspice	B-Algorithm
XVII	O
,	O
thus	O
older	O
versions	O
of	O
LTspice	B-Algorithm
do	O
n't	O
support	O
Unicode	O
.	O
</s>
<s>
Unicode	O
(	O
U+00B5	O
)	O
µ	O
micro	O
character	O
as	O
an	O
alternate	O
symbol	O
for	O
ASCII	B-Protocol
(	O
hex	O
75	O
)	O
u	O
letter	O
,	O
which	O
used	O
as	O
the	O
micro	O
(	O
10−6	O
)	O
scale	O
factor	O
.	O
</s>
<s>
See	O
option	O
setting	O
at	O
LTspice	B-Algorithm
->	O
Tools	O
->	O
Control	O
Panel	O
->	O
Netlist	O
Options	O
->	O
Convert	O
'	O
µ	O
 '	O
to	O
'	O
u	O
 '	O
.	O
</s>
<s>
Unicode	O
(	O
U+2212	O
)	O
−	O
minus	O
character	O
as	O
an	O
alternate	O
symbol	O
for	O
ASCII	B-Protocol
(	O
hex	O
2D	O
)	O
−	O
minus/dash/hyphen	O
character	O
.	O
</s>
<s>
See	O
option	O
setting	O
at	O
LTspice	B-Algorithm
->	O
Tools	O
->	O
Control	O
Panel	O
->	O
SPICE	B-Protocol
->	O
Accept	O
3K4	O
as	O
3.4K	O
.	O
</s>
<s>
LTspice	B-Algorithm
does	O
not	O
support	O
the	O
following	O
features	O
:	O
</s>
<s>
LTspice	B-Algorithm
does	O
not	O
support	O
scale	O
factors	O
of	O
"	O
atto	O
"	O
10−18	O
,	O
"	O
peta	O
"	O
1015	O
,	O
or	O
"	O
exa	O
"	O
1018	O
.	O
</s>
<s>
HSPICE	O
supports	O
'	O
a	O
 '	O
for	O
"	O
atto	O
"	O
10−18	O
,	O
which	O
must	O
be	O
replaced	O
with	O
'	O
e-18	O
'	O
to	O
be	O
compatible	O
with	O
LTspice	B-Algorithm
and	O
other	O
SPICE	B-Protocol
software	O
.	O
</s>
<s>
HSPICE	O
supports	O
'	O
X	O
 '	O
as	O
a	O
synonym	O
for	O
"	O
meg	O
"	O
106	O
,	O
which	O
must	O
be	O
replaced	O
with	O
'	O
e6	O
 '	O
or	O
'	O
MEG'to	O
be	O
compatible	O
with	O
LTspice	B-Algorithm
and	O
other	O
SPICE	B-Protocol
software	O
.	O
</s>
<s>
In	O
LTspice	B-Algorithm
,	O
a	O
node/net	O
(	O
connection	O
point	O
)	O
on	O
the	O
schematic	B-Application
can	O
be	O
labeled	O
by	O
using	O
the	O
Label	O
Net	O
tool	O
button	O
or	O
F4	O
key	O
.	O
</s>
<s>
Historically	O
,	O
SPICE	B-Protocol
and	O
older	O
version	O
of	O
LTspice	B-Algorithm
software	O
only	O
supported	O
printable	O
ASCII	B-Protocol
characters	I-Protocol
for	O
node/net	O
names	O
,	O
then	O
LTspice	B-Algorithm
XVII	O
added	O
support	O
for	O
Unicode	O
characters	O
.	O
</s>
<s>
For	O
example	O
,	O
"	O
_RESET	O
"	O
is	O
shown	O
on	O
the	O
schematic	B-Application
as	O
""	O
.	O
</s>
<s>
When	O
a	O
node/net	O
name	O
is	O
placed	O
on	O
a	O
schematic	B-Application
,	O
it	O
will	O
have	O
one	O
of	O
five	O
different	O
visual	O
representations	O
.	O
</s>
<s>
Many	O
of	O
the	O
LTspice	B-Algorithm
files	O
are	O
stored	O
as	O
an	O
ASCII	B-Protocol
text	I-Protocol
file	I-Protocol
,	O
which	O
can	O
be	O
viewed	O
or	O
edited	O
with	O
any	O
ASCII	B-Protocol
text	I-Protocol
editor	O
programs	O
.	O
</s>
<s>
One	O
of	O
the	O
side	O
benefits	O
of	O
an	O
ASCII	B-Protocol
file	I-Protocol
format	O
is	O
that	O
a	O
schematic	B-Application
can	O
be	O
listed	O
in	O
a	O
printed	O
document	O
/	O
book	O
/	O
magazine	O
/	O
datasheet	O
/	O
research	O
paper	O
/	O
homework	O
assignment	O
,	O
which	O
allows	O
the	O
reader	O
to	O
recreate	O
LTspice	B-Algorithm
files	O
without	O
electronic	O
file	O
distribution	O
.	O
</s>
<s>
LTspice	B-Algorithm
filename	O
extensions	O
:	O
</s>
<s>
.asc	O
-	O
schematic	B-Application
.	O
</s>
<s>
It	O
consists	O
of	O
a	O
netlist	O
based	O
on	O
SPICE	B-Protocol
text-based	O
commands	O
.	O
</s>
<s>
.asy	O
-	O
electronic	O
symbol	O
shown	O
in	O
a	O
schematic	B-Application
.	O
</s>
<s>
.plt	O
-	O
waveform	O
viewer	O
plot	B-Application
settings	O
.	O
</s>
<s>
.raw	O
-	O
binary	O
output	O
,	O
optional	O
ASCII	B-Protocol
output	O
.	O
</s>
<s>
The	O
following	O
example	O
can	O
be	O
viewed	O
by	O
copying	O
each	O
into	O
two	O
different	O
text	B-General_Concept
files	I-General_Concept
.	O
</s>
<s>
For	O
each	O
,	O
copy	O
the	O
text	O
in	O
the	O
gray	O
box	O
from	O
this	O
article	O
,	O
paste	O
into	O
an	O
ASCII	B-Protocol
text	I-Protocol
editor	O
,	O
saving	O
as	O
a	O
text	B-General_Concept
file	I-General_Concept
.	O
</s>
<s>
To	O
see	O
it	O
,	O
opening	O
the	O
"	O
asc	O
"	O
file	O
with	O
LTspice	B-Algorithm
then	O
click	O
the	O
"	O
Run	O
"	O
button	O
inside	O
LTspice	B-Algorithm
software	O
.	O
</s>
<s>
LTspice	B-Algorithm
schematics	B-Application
are	O
stored	O
as	O
an	O
ASCII	B-Protocol
text	I-Protocol
file	I-Protocol
with	O
a	O
filename	O
extension	O
of	O
"	O
asc	O
"	O
.	O
</s>
<s>
The	O
following	O
example	O
shows	O
the	O
contents	O
from	O
a	O
small	O
LTspice	B-Algorithm
schematic	B-Application
file	O
for	O
a	O
simple	O
RC	B-Algorithm
circuit	I-Algorithm
with	O
four	O
schematic	B-Application
symbols	O
:	O
V1	O
is	O
10	O
volt	O
DC	O
voltage	O
source	O
,	O
R1	O
is	O
1K	O
ohm	O
resistor	O
,	O
C1	O
is	O
1	O
uF	O
capacitor	O
,	O
ground	O
.	O
</s>
<s>
The	O
bottom	O
three	O
TEXT	O
lines	O
are	O
:	O
1	O
)	O
a	O
transient	O
simulation	O
directive	O
with	O
a	O
stop	O
time	O
parameter	O
of	O
10	O
ms	O
(	O
.tran	O
10mS	O
)	O
,	O
2	O
)	O
a	O
SPICE	B-Protocol
directive	O
to	O
set	O
the	O
initial	O
condition	O
of	O
RC	O
"	O
out	O
"	O
net	O
to	O
zero	O
volts	O
(	O
.ic	O
v(OUT )	O
=	O
0V	O
)	O
,	O
and	O
3	O
)	O
a	O
text	O
comment	O
(	O
title	O
)	O
.	O
</s>
<s>
LTspice	B-Algorithm
waveform	O
viewer	O
plot	B-Application
settings	O
are	O
stored	O
as	O
an	O
ASCII	B-Protocol
text	I-Protocol
file	I-Protocol
with	O
a	O
filename	O
extension	O
of	O
"	O
plt	O
"	O
.	O
</s>
<s>
If	O
this	O
optional	O
plot	B-Application
file	O
is	O
present	O
,	O
then	O
all	O
plot	B-Application
planes	O
will	O
automatically	O
be	O
displayed	O
after	O
the	O
"	O
Run	O
"	O
button	O
is	O
pressed	O
,	O
otherwise	O
the	O
user	O
will	O
need	O
to	O
click	O
on	O
each	O
net	O
to	O
see	O
the	O
waveform(s )	O
.	O
</s>
<s>
To	O
create	O
a	O
plot	B-Application
file	O
on	O
Windows	B-Application
,	O
after	O
a	O
plot	B-Application
graph	O
is	O
displayed	O
,	O
right-click	O
on	O
it	O
and	O
choose	O
"	O
File	O
"	O
,	O
then	O
choose	O
"	O
Save	O
Plot	B-Application
Settings	O
"	O
.	O
</s>
<s>
The	O
following	O
example	O
for	O
the	O
above	O
schematic	B-Application
shows	O
settings	O
for	O
a	O
"	O
transient	O
analysis	O
"	O
simulation	O
with	O
two	O
waveforms	O
on	O
one	O
plot	B-Application
plane	O
consisting	O
of	O
the	O
RC	O
voltage	O
at	O
"	O
out	O
"	O
net	O
and	O
current	O
through	O
resistor	O
R1	O
,	O
which	O
are	O
labeled	O
V(out )	O
and	O
I(R1 )	O
at	O
the	O
top	O
of	O
the	O
plot	B-Application
graph	O
.	O
</s>
