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PSpice and LTSpice

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petrus bitbyter

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Jan 4, 2010, 5:33:54 PM1/4/10
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Lately I got a PSpice listing that differs wildly from the LTSpice listings
used by LTSpice. Anyone knows a way to convert from PSpice to LTSpice?

petrus bitbyter


Jim Thompson

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Jan 4, 2010, 6:10:13 PM1/4/10
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Post a sample. Shouldn't be any _significant_ difference... maybe
polynomial versus behavioral ??

...Jim Thompson
--
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| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
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| Voice:(480)460-2350 Fax: Available upon request | Brass Rat |
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I love to cook with wine. Sometimes I even put it in the food.

petrus bitbyter

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Jan 5, 2010, 5:13:56 AM1/5/10
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"Jim Thompson" <To-Email-Use-Th...@My-Web-Site.com/Snicker>
schreef in bericht news:n8t4k5l76l2km0du6...@4ax.com...

I add two listings that show the differences very clear.

The first is a listing of the circuit involved. A three pole Sallen-Key low
pass filter. I need it to filter the harmonics from a PWM-based sinewave
generator. So far I see too much remnants of the sample frequency - in the
19-20kHz range - on the o'scope. My LTSpice program does not recognize it.

The second you will recognize easily. It's a LTSpice listing of a very
different circuit laying around here. Guess I got it from this NG.

* Netlist generated by ActiveLP
* --- Active Low-Pass Filter ----
* Filter Topologie: Sallen-Key
* Filter Type: Butterworth
* Filter Order: 3
* -3 dB-Frequency: 300 Hz
V1 O0 0 AC 1 0 PULSE(0 1 0 33.333u 33.333u 33.333m)
* Ideal Circuit using Voltage controlled Voltage Sources
RI1A O0 BI1 112.88
CI1A BI1 0 4.7u
EI1 OI1 0 BI1 0 1
RI2A OI1 AI2 78.805
RI2B AI2 BI2 162.34
CI2A BI2 0 2.2u
CI2B AI2 OI2 10u
EI2 OI2 0 BI2 0 1
.graph OI2 curveLabel="Output Stage 2 Ideal" nowarn=true ylog=auto
* Simulation Control
.TRAN 0 66.667m 0 33.333u
.AC DEC 1k 3 3k


Version 4
SHEET 1 2100 1172
WIRE 848 -416 752 -416
WIRE 1040 -416 928 -416
WIRE 752 -304 752 -416
WIRE 848 -304 752 -304
WIRE 1040 -304 1040 -416
WIRE 1040 -304 912 -304
WIRE 1104 -304 1040 -304
WIRE 1152 -304 1104 -304
WIRE 752 -272 752 -304
WIRE 752 -160 752 -208
FLAG 752 -160 0
FLAG 1104 -304 out
SYMBOL Digital\\schmtinv 848 -368 R0
WINDOW 3 30 111 Left 0
WINDOW 123 34 145 Left 0
SYMATTR InstName A1
SYMATTR Value vhigh=5 vlow=0 trise=25n
SYMATTR Value2 tripdt=5n vt=2.5 vh=.9
SYMBOL cap 736 -272 R0
SYMATTR InstName C2
SYMATTR Value 100n ic=0
SYMBOL Misc\\EuropeanResistor 832 -400 R270
WINDOW 0 27 56 VTop 0
WINDOW 3 5 56 VBottom 0
SYMATTR InstName R1
SYMATTR Value 100k
TEXT 536 -392 Left 0 !.tran 0 200m 0 uic


petrus bitbyter


Ian Bell

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Jan 5, 2010, 8:16:40 AM1/5/10
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If you are looking for compatibility between these two programs at the
schematic level you will be sadly disappointed. You simply need to draw
the circuit in LTSpice then simulate it.

Cheers

Ian

Jim Thompson

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Jan 5, 2010, 10:28:20 AM1/5/10
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On Tue, 5 Jan 2010 11:13:56 +0100, "petrus bitbyter"
<pieterkral...@enditookhccnet.nl> wrote:

Above is a NETLIST.

Below is a SCHEMATIC.

Here are some discussions of netlist-to-schematic conversion...

http://www.nandigits.com/goftrace.htm

http://portal.acm.org/citation.cfm?id=622491

None that I know of actually work well.

The above netlist is simple, translate it by hand ;-)

Also, I am SURE that there is some way to import a netlist into
LTspice _without_ having to translate it to a schematic.

LTspice users?

qrk

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Jan 5, 2010, 3:24:41 PM1/5/10
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On Mon, 4 Jan 2010 23:33:54 +0100, "petrus bitbyter"
<pieterkral...@enditookhccnet.nl> wrote:

LTspice is very compatible with PSpice netlists. When you do a
File>Open in LTspice, be sure you select Netlists as the file type.

To make life easier, take the PSpice netlist and draw a schematic from
it in LTspice. It's such a small circuit that you should be able to do
this in 10 minutes.

--
Mark

Helmut Sennewald

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Jan 5, 2010, 6:30:51 PM1/5/10
to
"petrus bitbyter" <pieterkral...@enditookhccnet.nl> schrieb im
Newsbeitrag news:4b4310ea$0$7031$e4fe...@dreader32.news.xs4all.nl...

Hello Petrus,

You could directly run the netlist if you comment the .AC and the .Graph
line.
Below is this netlist file "test4.cir". It's ready to be used with LTspice.

* Netlist generated by ActiveLP
* --- Active Low-Pass Filter ----
* Filter Topologie: Sallen-Key
* Filter Type: Butterworth
* Filter Order: 3
* -3 dB-Frequency: 300 Hz
V1 O0 0 AC 1 0 PULSE(0 1 0 33.333u 33.333u 33.333m)
* Ideal Circuit using Voltage controlled Voltage Sources
RI1A O0 BI1 112.88
CI1A BI1 0 4.7u
EI1 OI1 0 BI1 0 1
RI2A OI1 AI2 78.805
RI2B AI2 BI2 162.34
CI2A BI2 0 2.2u
CI2B AI2 OI2 10u
EI2 OI2 0 BI2 0 1

*.graph OI2 curveLabel="Output Stage 2 Ideal" nowarn=true ylog=auto


* Simulation Control
.TRAN 0 66.667m 0 33.333u

*.AC DEC 1k 3 3k


I have additionally made a schematic of this netlist.
It is 100% equivalent to the original netlist.
Schematic file "test4a.asc".

Best regards,
Helmut

Version 4
SHEET 1 1308 680
WIRE 768 -16 592 -16
WIRE 912 -16 832 -16
WIRE 32 80 0 80
WIRE 80 80 32 80
WIRE 224 80 160 80
WIRE 240 80 224 80
WIRE 336 80 240 80
WIRE 400 80 384 80
WIRE 448 80 400 80
WIRE 560 80 528 80
WIRE 592 80 592 -16
WIRE 592 80 560 80
WIRE 640 80 592 80
WIRE 752 80 720 80
WIRE 768 80 752 80
WIRE 864 80 768 80
WIRE 912 80 912 -16
WIRE 976 80 912 80
WIRE 0 144 0 80
WIRE 240 144 240 80
WIRE 384 144 384 80
WIRE 912 144 912 80
WIRE 336 160 336 80
WIRE 864 160 864 80
WIRE 768 176 768 80
WIRE 0 288 0 224
WIRE 240 288 240 208
WIRE 240 288 0 288
WIRE 336 288 336 208
WIRE 336 288 240 288
WIRE 384 288 384 224
WIRE 384 288 336 288
WIRE 768 288 768 240
WIRE 768 288 384 288
WIRE 864 288 864 208
WIRE 864 288 768 288
WIRE 912 288 912 224
WIRE 912 288 864 288
WIRE 0 304 0 288
FLAG 32 80 O0
FLAG 224 80 BI1
FLAG 0 304 0
FLAG 400 80 OI1
FLAG 560 80 AI2
FLAG 752 80 BI2
FLAG 976 80 OI2
IOPIN 976 80 Out
SYMBOL voltage 0 128 R0
WINDOW 3 -34 220 Left 0
WINDOW 123 -32 246 Left 0
WINDOW 39 0 0 Left 0
SYMATTR InstName V1
SYMATTR Value PULSE(0 1 0 33.333u 33.333u 33.333m 100m)
SYMATTR Value2 AC 1
SYMBOL res 64 96 R270
WINDOW 0 32 56 VTop 0
WINDOW 3 0 56 VBottom 0
SYMATTR InstName RI1A
SYMATTR Value 112.88
SYMBOL cap 224 144 R0
SYMATTR InstName CI1A
SYMATTR Value 4.7�
SYMBOL e 384 128 R0
SYMATTR InstName EI1
SYMATTR Value 1
SYMBOL res 432 96 R270
WINDOW 0 32 56 VTop 0
WINDOW 3 0 56 VBottom 0
SYMATTR InstName RI2A
SYMATTR Value 78.805
SYMBOL res 624 96 R270
WINDOW 0 32 56 VTop 0
WINDOW 3 0 56 VBottom 0
SYMATTR InstName RI2B
SYMATTR Value 162.34
SYMBOL cap 752 176 R0
SYMATTR InstName CI2A
SYMATTR Value 2.2�
SYMBOL e 912 128 R0
SYMATTR InstName EI2
SYMATTR Value 1
SYMBOL cap 768 0 R270
WINDOW 0 32 32 VTop 0
WINDOW 3 0 32 VBottom 0
SYMATTR InstName CI2B
SYMATTR Value 10�
TEXT 0 -40 Left 0 !.TRAN 0 66.667m 0 33.333u
TEXT 0 -80 Left 0 ;.AC DEC 1k 3 3k


Marte Schwarz

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Jan 6, 2010, 6:00:20 PM1/6/10
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Hi Jim,

> Above is a NETLIST.
>
> Below is a SCHEMATIC.

> Also, I am SURE that there is some way to import a netlist into


> LTspice _without_ having to translate it to a schematic.
>
> LTspice users?

I'm not a SPICE expert but this is very easy. Insert a Text as Spice
directive in the plain schematic and then run the simulation as is. In this
example the line

.graph OI2 curveLabel="Output Stage 2 Ideal" nowarn=true ylog=auto

should be eliminated with a semicolon in the beginning. Also you have to
decide whether you want to simulate .Tran or .AC

May be there is a more elegant way to do but this one is simple to use

Marte


Jim Thompson

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Jan 6, 2010, 6:46:34 PM1/6/10
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See....

http://www.analog-innovations.com/SED/SubcircuitImportByNetlist.pdf

This is how I include a client's existing chip, or cell's the client
has designed, without having to draw those sections with a schematic
editor.

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