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I use
.ac dec 201 10 100k
then how do I make an output table of
V(out) at specific frequencies?

I'm sure you can have LTspice print a table from the plot window. In
the old days of SPICE, that was how you got your data: in tabular
form, without the plots. LTspice relies on the visual presentation
and did away with the default tabular data. I would check the SPICE
Error Log anyway, just in case it still puts the AC data there.
(The old SPICE command to get AC data was:
.PRINT AC VM(n004) VP(n004) IM(r6) IP(r6) VR(out) VI(out)
etc.)

is there a way to say, ask for
V(out) at freq=20.5956780Hz?
V(out) at freq=33.4585746Hz

The good news is, unlike a TRANsient analysis, an AC analysis actually
does a pre-determined set of frequencies. Transient analysis depends
on being able to vary the step size dynamically, so you never get
uniform time steps. Not so with AC analysis. The frequency steps are
deterministic and you know in advance exactly what frequencies you
will get.

Unfortunately, you have limited capability to ask for specific
frequencies. As far as I know you can only specify a frequency range;
not a table of frequencies. (Perhaps that could be suggested to Mike
as a future enhancement to LTspice.) You get what you get, and you
need to interpolate if you want data in between. (MS-Excel or a math
program comes in handy here.)

On the other hand, it would be tedious, but I suppose you could set
your start and stop frequencies to two of the frequencies you actually
need, such as
.AC lin 0 20.5956780 33.4585746
and repeat as necessary. I get the feeling you have a huge number of
odd frequencies, that don't fall on a nice linear or logarithmic sweep.
With a bit of programming there is probably a way to automate the
process ... generate multiple netlists, simulate, grab the data, store
it and assemble into one file.

Regards,
Andy

I'm looking for transistor models for
2N6083 and 2N5591

thanks, Frank

oops, sent this before thought of this:

is there a way to supply a table of frequencies and have the ac analysis specifically done at those points, yet plot the results too? At least an output table would help.

like
f(1)=20.5956780Hz
f(2)=33.4585746Hz
.
.
.


and that would generate a table of
V(out) at f(1)
V(out) at f(2)
.
.
.

and so on.

of course need access to the table.

Is there a way to use
.ac dec 500 10 100k
and a .meas command to yield a table of values?

that at least would get me by for awhile.

--- macy@... wrote:

From: Macy <macy@...>
To: <LTspice@...>
Subject: Re: [LTspice] Help! How do I do find maximum signal easily!
Date: Fri, 12 Jul 2013 02:47:06 -0700

Andy, thanks for responding. I forgot to add after asking if this was a stupid question, whether I had worded it badly.

How about this:

I use
.ac dec 201 10 100k
then how do I make an output table of
V(out) at specific frequencies?

I can change the command line to
.ac dec 500 10 100k
which is only 2000 points, and not slow down the analysis much

is there a way to say, ask for
V(out) at freq=20.5956780Hz?
V(out) at freq=33.4585746Hz
.
.
.
and so on to make a table of these values that I could then use elsewhere?




--- Andrew.Ingraham@... wrote:

From: Andy <Andrew.Ingraham@...>
To: LTspice@...
Subject: Re: [LTspice] Help! How do I do find maximum signal easily!
Date: Thu, 11 Jul 2013 23:26:31 -0400

I can't believe no one has responded! Was this a stupid question?

Maybe not. But a complicated one. I, for one, have trouble understanding
what exactly you are asking. Sorry.

Andy

Andy, thanks for responding. I forgot to add after asking if this was a stupid question, whether I had worded it badly.

How about this:

I use
.ac dec 201 10 100k
then how do I make an output table of
V(out) at specific frequencies?

I can change the command line to
.ac dec 500 10 100k
which is only 2000 points, and not slow down the analysis much

is there a way to say, ask for
V(out) at freq=20.5956780Hz?
V(out) at freq=33.4585746Hz
.
.
.
and so on to make a table of these values that I could then use elsewhere?




--- Andrew.Ingraham@... wrote:

From: Andy <Andrew.Ingraham@...>
To: LTspice@...
Subject: Re: [LTspice] Help! How do I do find maximum signal easily!
Date: Thu, 11 Jul 2013 23:26:31 -0400

I can't believe no one has responded! Was this a stupid question?

Maybe not. But a complicated one. I, for one, have trouble understanding
what exactly you are asking. Sorry.

Andy

Ich bin noch relativ neu in LTSPICE unterwegs und brauche Hilfe. Ich soll die neuesten IGBTs von Infineon mit LTSpice testen.
Wie mir meine Kollegen mitgeteilt haben, ist das Problem mit den Infineon Libs bekannt, aber keiner hat eine L?sung parat...
Es handelt sich um folgende LIB: IXX_N60H3_L2.lib
Ich habe den Typ "IKW50N60H3_L2" eingesetzt und die Simulatin hat nach wenigen Mikrosekunden abgebrochen...
Gibt es bekannte Ursachen der kann es an der Schaltung liegen? Ich kann ja noch das *asc File posten...
Ich w?re an einer schnellen L?sung interessiert.

Danke Gru? Kalle

Hello Hamed,

I had a chance to look at this a bit more closely, and I do think LTspice is having a problem with this circuit that it should not have. I have created a simpler version of your circuit, in schematic form, and placed it in the Temp directory. The file is "BadExp.asc." If you run it as-is the simulator fails to find a reasonable solution, voltages and currents that should be in the single-digits are in the 100ks or Megs, not where they should be. However if you change the simulation command to start the DC sweep at 0V instead of -1V it works fine. This is what I saw with your circuit too, I think having two cells in series might have caused the simulator, at some point in its search, to have a negative voltage on one of the cells, and everything blew up. It seems that LTspice tries to use the results of each iteration to start the next iteration, so once it's gone off the rails it stays there. But it really shouldn't be having any problem calculating the solution with negative input voltages.

Another way to 'fix' the problem is to force the B-source for Voc to a constant value of 0.564V. This is odd since even when the sim fails that B-source has that correct value on it, while the Bidiode source blows up.

I have sent this circuit and observation to Mike @ LT, I'll report back here when I hear from him.

--- In LTspice@..., "hamed" <l0st_l0rd@...> wrote:

the reason that I use arbitrary model not a standard diode is that I cannot control temperature change for each solar cell in diode model.

But as you've been told this is not true. You -can- control the temperature independently for each instance. What's more, the standard model will have the correct temperature dependence while you already know that your equations do not calculate Voc correctly over temperature.

--- In LTspice@..., "hamed" <l0st_l0rd@...> wrote:

Furthermore, the reason that grounds are different is that two cells are in series.

Yes, I understand why you want your model to float so you can connect them without reference to ground, but as I said you did not implement this correctly. Your formulas for Voc and Isc are referenced to the 'ref' node but then when you use those values in the subsequent calculations you are using their value relative to ground. This is wrong.

Actually I should say that I am not so good in schematics environment and I am used to netlists while I can control the nodes easier.

You should give it a try, with very little practice I think you will find that it's actually much easier to keep track of what nodes are connected where by looking at the schematic than it is by reading a large netlist. I suggest again that you might not have made the errors with the signal references if you had used a schematic instead of a netlist.

Best,
Fred

--- In LTspice@..., "qrx3" <fredh@> wrote:

Hello Hamed,

While I would also advise you to use a standard diode model instead of building your own, I may be able to shed some light on your difficulty.

Note that your derived values for ISC and VOC are generated in relation to the reference input 'ref'. However when you use these values in your formulae you are using the value relative to ground:

log((v(isc)/{i0})+1)

The same is true when you use the input voltage:

(v(inp)*iscr)/1000)

I have not tried to run your circuit, but I strongly suspect this is why it would work for a single cell where ref = ground and not for a second cell where ref != ground.

I think the most sensible fix would be to reference eisc and evoc to ground instead of ref, so you can observe the values externally if you want and not have to subtract the ref voltage. Then change "v(inp)" for example to "v(inp,ref)" where needed.

I suggest that if you had drawn this as a circuit instead of writing a netlist these issues would have been quickly apparent, but maybe not.

Cheers,
Fred

--- In LTspice@..., "hamed" <l0st_l0rd@> wrote:

Dear friends

in the file below you can find an arbitrary solar cell.
When I put two cells in parallel the answer is correct and when I put them in
series I see a distortion.
I think the problem is related to the diode behavioral model.

I will be thankful if any of you could help me.



sincerely,
Hamed

It might be worth checking sparkfun.com for information on this link. I
have read that they use eagle for production, and make available most (if
not all) of there schematics and symbols. Also, since they use eagle for
production, they may have an inside track to getting support, as they can
influence a large user base.

Tim


On Sun, Jul 7, 2013 at 9:49 AM, bdd4@... <bdd4@...> wrote:

**


Try the Cadsoft offcie in Florida. They have always been extremely
helpful. I was sorry when Newark bought them and was afraid those who
usually helped me might get eliminated.

--- In LTspice@..., "boB G" <bob@...> wrote:

I went looking on the eagle forums for answers on this too only to find

that it looks like the eagle forums are no longer there.

what link are you using to get to the eagle forums now ? even if

unanswered ?

thanks,
boB


--- In LTspice@..., "Gandolf" <gandolf_t_grey@> wrote:

Some background, not intended to be criticism, then the question.

Cadsoftusa's Eagle 6.4 introduced an interface to link schematics with

LTSpice IV for simulation. Unfortunately, the link does not seem to be
fully functional. There is no documentation from Cadsoftusa about this link
that I have been able to find. Cadsoftusa's website points to Newark
(Element 14) for technical support. Newark (Element 14) has a number of
Eagle Webcasts but these have provided limited help. Also, their forum
questions go un-answered. In fairness, Newark (Element 14) is in the
business of selling, not providing implementation details of a product;
they do provide LTSPice IV models and Eagle symbols and placement data for
many components.

I have been able to create a link Eagle 6.4 to LTSpice IV but have not

been able to transfer a schematic for simulation.

Separately, I have been able to download spice models and symbols and

integrate them into LTSpice IV for simulation.

Separately, I have been able to download and integrate schematic

symbols and placement data into Eagle 6.4.

Getting the two products to work an play together seem to be

problematic.

The Question: Has anyone in the forum had any experience with using

the Eagle 6.4 link to LTSpice IV and can provide any guidance or point to
potential information.

Using a link like this seems to be a good idea and I would like to

take advantage of it. I'll keep trying different things as time permits.

[Non-text portions of this message have been removed]

I can't believe no one has responded! Was this a stupid question?

Maybe not. But a complicated one. I, for one, have trouble understanding
what exactly you are asking. Sorry.

Andy

I can't believe no one has responded! Was this a stupid question?


--- macy@... wrote:

From: Macy <macy@...>
To: <LTspice@...>
Subject: [LTspice] Help! How do I do find maximum signal easily!
Date: Wed, 10 Jul 2013 17:43:31 -0700

I'm trying to find an easy way to see if my signal saturates any OpAmp output, or violates some level to the next stage.

Right now, I'm using input values predetermined from matching to the existing breadboard circuit I know the levels are ok, but now I want to redesign using simulation.

Problem is...I have a VERY complex time input signal yet has fairly 'flat' harmonic content, so historically I have been able to use AC analysis and get very accurate simulation. for example, a representative data point using most recent LTspice I predict 35 ppm noise at 1kHz [that is, noise to signal levels] and MEASURE 36 ppm. So am very happy with the simulation and models. [the noise pretty much matches within 10% over the rest of the spectrum]

Here is the problem. I want to redesign the circuit, but not build it to verify operating levels. So how do I bounce between this frequency domain and the time domain WITHOUT taking days for each run?

What I mean is, I can represent the input waveform in a .wav form or PWL model, but we're talking 4400 UNIQUE data points that repeat and repeat. then, do .tran analysis, but that takes iteration after iteration to get a stable repeatable output signal.

Or, I could 'post-process' an AC analysis by just 'assuming' everything is copacetic, run the AC analysis, and find the harmonic values/phase angles and use octave to plot the signal. And, octave will tell me if I've violated maximum signal level.

How do I make the AC simulation put out specific frequency/phase values, maybe not the ones it used during the AC analysis? And how accurate will they be? The signal may be complex enough that a few degrees could cause a catastrophe, but I guess I could cross that bridge later, getting close right now would be a big help.

Is there a way to make a file of table of results? I give frequency points [not in the AC anlayis] and LTspice gives me amplitude/phase in a file, so I can run that through octave. Is there a way to 'force' the frequency data points of LTspice - there's a lot fo them?

Or, is there a way to stay in the time domain easily quickly generate the waveform as I change a component value someplace?

Help!

Hi,

I don't know what your specific requirements are, but have you taken a
look at the "AT-42086", made by Agilent (HP), it may meet your
requirements. I have over 18,000 (18K) of these things on tape reels.
(Don't ask!) If you (or anyone else for that matter) will sent me a
SASE, I will send you 1 oz worth. I guess about 20 to 40. I only ask
that you or anyone keep us posted on any circuits that you have success
with.

On another thought have you looked at the Norton-Rohde Feedback
Amplifier? See


Also, the datasheet shows the typical scattering parameters for an
output impedance of 50 ohms from 100 MHz to 6.0 GHz. I would be
eternally grateful for anyone who can develop a LTSpice model for 100
MHz and 2.5 GHz.

Glynn ..
K4RKI
AMA30686

PS; Google my ham radio call sign and you will find my address in the
FCC database. Or K4RKI@...

I am inquiring about power transistor models...
the devices are:

2n5591 or 2n6083

thank you.....Frank

I am looking for power transistor models for the following devices:

2N6083 or 2N5591

thank you for your help...

Frank

--- In LTspice@..., Andy <Andrew.Ingraham@...> wrote:

I think what's happening here is that your circuit has two possible stable
states, due to the fact that it has no real V+ supply voltage. If the
op-amp happens to start up yanking on the output pin, it will pull the
positive supply pin voltage down with it so that it goes low, and then it
settles on that second stable operating point, with the output pin
negative. In that state, the op-amp is open-loop and essentially broken.

If that doesn't happen, it lets the output pin (and the positive supply
voltage) go high, and the negative feedback works normally.

With it being a roll-of-the-dice which stable state comes up, a change to
one part of the circuit can cause a change elsewhere.

To prove that there are (at least) two stable states I did the following.

I added a .NODESET V(n010)=10V to the circuit where U1 was replaced by the
UniversalOpamp2, and this makes U2 come up "normally" again.

I tried adding a .NODESET V(n010)=-2.5V to the un-modified circuit. This
seems to cause LTspice to go into spasms where it can't find a clean
operating point to start the transient simulation with, but it runs anyway
and the transient simulation waveforms indicate that it doesn't ever
recover to the "normal" situation where there is a good positive supply
voltage. In other words, it finds the second stable operating point where
U2 is open-loop, and its output remains low.

This is a very poorly behaved negative feedback circuit. Highly
questionable design.

Regards,
Andy


[Non-text portions of this message have been removed]

That's great detective work and analysis! You've shown me a new tool to use in future troubleshooting attempts.

Yes, I know the circuit is strange . . . I inherited it from a customer and was running some simulations in order to understand the functions and problems. The reason for the strangeness is that it runs a the end of a long twisted pair, and the power line is also the signal line. I added the -5V negative rail in an attempt to get the simulation running, since the opamp I selected drew 5 times the current of the part they were using, unbalancing the design. I may try to give them an alternate power+signal 2-wire design that is inherently stable.

Thanks,
Carl

Hi Helmut,

Thanks again. I'll take another look at it and see if this time the penny drops :-)

Greetings,

Jesper

Hello Ross,

unfortunately neither by Analog Devices nor in the internet is a .subckt ADCMP566 to find.

:-(

Leo

Hi does anyone have a model for the ADCMP566 comparator
regards
Ross

Hi Ferdian Cahyodwiputro.
You gave yourself the problem from scratch.
Using the command ". Inc" or ". Lib" you have to enter into it full name.
In my electronic circuit: .inc 2SC5006.txt.
If you like the LIB file extension, then copy my file 2SC5006.txt to a file 2SC5006.lib.
Bordodynov.

11.07.2013, 11:42, "Ferdian Cahyodwiputro" <ferdiancahyodwiputro@...>:

Hi Mr.Александр Бордодынов

i was download your file but cannot open in LTspice because format not .lib.
can you upload again with format .lib for component transistor 2SC5006?



________________________________
From: Александр Бордодынов <BordodunovAlex@...>
To: "LTspice@..." <ltspice@...>
Sent: Wednesday, July 10, 2013 7:53 PM
Subject: Re: [LTspice] low noise amplifier



?
Hi Ferdian Cahyodwiputro.
I created a small electronic circuit to test the model. Using this scheme, I found that the description of the transistor pins are in non-standard order. I will put circuit in the TEMP folder.
Bordodynov.

10.07.2013, 15:33, "Ferdian Cahyodwiputro" <ferdiancahyodwiputro@...>:

Hi Mr. Александр Бордодынов
can you upload this component? because i still can't understand to create new component..
i'm still newbe

________________________________
From: Ferdian Cahyodwiputro <ferdiancahyodwiputro@...>
To: "LTspice@..." <LTspice@...>
Sent: Wednesday, July 10, 2013 6:22 PM
Subject: Re: [LTspice] low noise amplifier

thank you..

this conversation helpfull my trouble.

________________________________
From: Александр Бордодынов <BordodunovAlex@...>
To: "LTspice@..." <ltspice@...>
Sent: Wednesday, July 10, 2013 5:06 PM
Subject: Re: [LTspice] low noise amplifier

==>HELP==>F.A.Q==>Third-party Models-->
.....
Example for a 3-pin NPN transistor but defined with a .SUBCKT statement:
.....

Bordodynov.

10.07.2013, 13:55, "Ferdian Cahyodwiputro" <ferdiancahyodwiputro@...>:

thank you for your information by the way so i must create new design symbol with this parameter?

________________________________
From: Александр Бордодынов <BordodunovAlex@...>
To: "LTspice@..." <ltspice@...>
Sent: Wednesday, July 10, 2013 12:21 PM
Subject: Re: [LTspice] low noise amplifier

Hi.
Model:

.SUBCKT q2SC5006_v111 7 8 9
Ccb 2 5 58f
Cce 2 6 87f
Cbe 7 9 0.67f
Cb 1 2 180f
Ce 2 3 180f
Lb 5 7 1.09n
Lc 2 8 0.79n
Le 6 9 0.99n
Lb2 1 5 0.004n
Le2 3 6 0.004n
Qnpn 2 1 3 q2SC5006_v111_M

.MODEL q2SC5006_v111_M NPN
+(IS=616e-18 BF=161 NF=0.99 VAF=50.0
+ IKF=1.5 BR=14.4 NR=0.99 VAR=2.4
+ IKR=0.32 ISE=38.2e-14 NE=2.19 ISC=80e-17
+ NC=1.0 RB=4.37 IRB=759e-6 RBM=2.23
+ RE=0.4 RC=5.0 CJE=2.21p VJE=0.954
+ MJE=0.408 CJC=1p VJC=0.667 MJC=0.408
+ XCJC=0.8
+ FC=0.50 TF=20.0e-12 XTF=1e-3 VTF=0.668
+ITF=9.7 TR=0 PTF=40 EG=1.11
+ XTI=3.0 XTB=0)
.ENDS q2SC5006_v111

Bordodynov.

10.07.2013, 08:20, "ferdiancahyodwiputro" <ferdiancahyodwiputro@...>:

dear everyone
i have toruble to design low noise amplifier.
i search transistor 2SC5006 in library LTspice but i can't found it.
please help me how to get transistor 2SC5006 in library LTspice

[Non-text portions of this message have been removed]

[Non-text portions of this message have been removed]

[Non-text portions of this message have been removed]

I think what's happening here is that your circuit has two possible stable
states, due to the fact that it has no real V+ supply voltage. If the
op-amp happens to start up yanking on the output pin, it will pull the
positive supply pin voltage down with it so that it goes low, and then it
settles on that second stable operating point, with the output pin
negative. In that state, the op-amp is open-loop and essentially broken.

If that doesn't happen, it lets the output pin (and the positive supply
voltage) go high, and the negative feedback works normally.

With it being a roll-of-the-dice which stable state comes up, a change to
one part of the circuit can cause a change elsewhere.

To prove that there are (at least) two stable states I did the following.

I added a .NODESET V(n010)=10V to the circuit where U1 was replaced by the
UniversalOpamp2, and this makes U2 come up "normally" again.

I tried adding a .NODESET V(n010)=-2.5V to the un-modified circuit. This
seems to cause LTspice to go into spasms where it can't find a clean
operating point to start the transient simulation with, but it runs anyway
and the transient simulation waveforms indicate that it doesn't ever
recover to the "normal" situation where there is a good positive supply
voltage. In other words, it finds the second stable operating point where
U2 is open-loop, and its output remains low.

This is a very poorly behaved negative feedback circuit. Highly
questionable design.

Regards,
Andy

I'm trying to find an easy way to see if my signal saturates any OpAmp output, or violates some level to the next stage.

Right now, I'm using input values predetermined from matching to the existing breadboard circuit I know the levels are ok, but now I want to redesign using simulation.

Problem is...I have a VERY complex time input signal yet has fairly 'flat' harmonic content, so historically I have been able to use AC analysis and get very accurate simulation. for example, a representative data point using most recent LTspice I predict 35 ppm noise at 1kHz [that is, noise to signal levels] and MEASURE 36 ppm. So am very happy with the simulation and models. [the noise pretty much matches within 10% over the rest of the spectrum]

Here is the problem. I want to redesign the circuit, but not build it to verify operating levels. So how do I bounce between this frequency domain and the time domain WITHOUT taking days for each run?

What I mean is, I can represent the input waveform in a .wav form or PWL model, but we're talking 4400 UNIQUE data points that repeat and repeat. then, do .tran analysis, but that takes iteration after iteration to get a stable repeatable output signal.

Or, I could 'post-process' an AC analysis by just 'assuming' everything is copacetic, run the AC analysis, and find the harmonic values/phase angles and use octave to plot the signal. And, octave will tell me if I've violated maximum signal level.

How do I make the AC simulation put out specific frequency/phase values, maybe not the ones it used during the AC analysis? And how accurate will they be? The signal may be complex enough that a few degrees could cause a catastrophe, but I guess I could cross that bridge later, getting close right now would be a big help.

Is there a way to make a file of table of results? I give frequency points [not in the AC anlayis] and LTspice gives me amplitude/phase in a file, so I can run that through octave. Is there a way to 'force' the frequency data points of LTspice - there's a lot fo them?

Or, is there a way to stay in the time domain easily quickly generate the waveform as I change a component value someplace?

Help!