开云体育

--- In LTspice@..., "s35148" <s35148@...> wrote:

Hi,

I'm having a problem with another program that use LTSpice to run the simulation. The schematic have a NAND gate, and I write a ".model" like the one below, but the LTSpice seems don't recognize the "d_nand" expression.

** 2 input NAND schmitt
.model A4093 d_nand ( in_family="4000-5_SCHMITT"

Hi

I have some simulations (one I am fighting with right this second) which use the 4093 NAND. My simulation uses a part from the CD4000.lib file that is in this group. (Look here: )

It's not a bad model, although the input thresholds and output levels are defined, but fixed (not changing with supply rails). I have added a behavioral source on the output for one of my simulations so that that it doesn't output more than the supply level, and I may have to put something on the input to similarly scale the thresholds for start-up simulations (or just do it the right way and build my own model!)

Hope that helps.

A.

--- In LTspice@..., "Tony Casey" <tony@...> wrote:

--- In LTspice@..., "Apparajan" <dg1@> wrote:

How do you measure frequency of an oscillator accurately in LTspice..( I probably need this for .disto to work well)
cheers
AG

Hello AG

.meas TRAN Trise find time when V(out)=0 rise=3
.meas TRAN Trise2 find time when V(out)=0 rise=4
.meas TRAN Tfall find time when V(out)=0 fall=3
.meas TRAN Ton param Tfall-Trise
.meas TRAN Period param Trise2-Trise
.meas TRAN Frequency param 1/(Trise2-Trise)
.meas TRAN DutyCycle param Ton/Period*100

... should cover most of your needs.

Regards,
Tony

Hi,

If there is a section in LTwiki to show examples for specific calculations, this would be a good example to be added under the title "Frequency and duty cycle".
I admit that for most of us this example is rather obvious but not for scared/confused users running a simulator for the first time :)

For the more complicated situations, I used to archive every solution I found adequate under an appropriate title that I can find easily by searching anytime later.

Kerim

--- In LTspice@..., Walking Through <walkingthrough@...> wrote:

Hello -

Last Thursday a simulation consisting of a 100 x 100 grid of resistors and capacitors was started.? I knew this was going to take a long time (transient response) and arranged for use of a dual-Xeon computer.

Simulation time was from 0 to 1 microsecond.

Returned Monday to find the simulation done and plots on the display.? In the past, LTspice saved the raw file and I could use ltsputil to retrieve data. Read: No, I didn't export the data before closing LTspice.

LTsputil says the raw file contained data to 27 nsec. Windows XP shows the raw file as 19K long.? Where did the other 973 nsec go?

Also....

How often do displayed waveforms get refreshed? I remember checking Thursday afternoon and seeing that 27 nsec... but while the display showed 1 usec on Monday, the rawfile only contained data to 27 nsec.

--Mark

Hello Mark,

I wonder about the slow simulation speed. You should help
LTspice with some settings(.options) to improve convergence.
This should reduce the simulation time by factors if not decades.

Best regards,
Helmut

Hello -

Last Thursday a simulation consisting of a 100 x 100 grid of resistors and capacitors was started.? I knew this was going to take a long time (transient response) and arranged for use of a dual-Xeon computer.

Simulation time was from 0 to 1 microsecond.

Returned Monday to find the simulation done and plots on the display.? In the past, LTspice saved the raw file and I could use ltsputil to retrieve data. Read: No, I didn't export the data before closing LTspice.

LTsputil says the raw file contained data to 27 nsec. Windows XP shows the raw file as 19K long.? Where did the other 973 nsec go?

Also....

How often do displayed waveforms get refreshed? I remember checking Thursday afternoon and seeing that 27 nsec... but while the display showed 1 usec on Monday, the rawfile only contained data to 27 nsec.

--Mark

Other than that, all are fine??please confirm..

shall i give clock signal for the nodes VIN_P, VIN_N, and VBIAS_P??

please confirm.

Thank you

Please help me on this and do the needful.

You left unconnected signal pins. Look at nodes VIN_P, VIN_N, and
VBIAS_P. Why do you have nothing connected to these pins?

I mean:
.meas TRAN Frequency param 1/Period

- sorry copy and paste error.

Regards,
Tony

--- In LTspice@..., "Apparajan" <dg1@...> wrote:

How do you measure frequency of an oscillator accurately in LTspice..( I probably need this for .disto to work well)
cheers
AG

Hello AG

.meas TRAN Trise find time when V(out)=0 rise=3
.meas TRAN Trise2 find time when V(out)=0 rise=4
.meas TRAN Tfall find time when V(out)=0 fall=3
.meas TRAN Ton param Tfall-Trise
.meas TRAN Period param Trise2-Trise
.meas TRAN Frequency param Trise2-Trise
.meas TRAN DutyCycle param Ton/Period*100

... should cover most of your needs.

Regards,
Tony

<Snip>
--- In LTspice@..., Tan Micheline Tambayong <micheline.tambayong@...> wrote:

Hi,
thanks so much for helping me solving the problem.. But both solution
(adding Roff and changing the ground position) are giving different results.
So I wonder which one should I use.

Also Tony, can you please explain to me what's actually Roff do in the
diode?

Thanks so much everyone..

Kind regards,
Micheline

</snip>
Hello Micheline,

All of the parameters of the diode model are explained in the LTspice>Circuit Elements>Diode section of the Help.

Regards,
Tony

--- In LTspice@..., "dinesh" <dinsul1986@...> wrote:

Can anyone tell me where can I find the file "tsmc90.lib"

Thank you.

Where did you last leave it? :-)

--- In LTspice@..., "Ian"<iw1904@...> wrote:

Hi,



The GND is in the wrong place.

Please see corrected circuit in TEMP folder



Regards


_____

I am using the Free version of SPAMfighter <>
.
SPAMfighter has removed 3438 of my spam emails to date.

Do you have a slow PC? <>
Try free scan!

Ian,

With respect, we don't know for sure where the circuit should be grounded, as we don't know what the application is. Perhaps the rectified bit should be floating?

Regards,
Tony

Hi,

I had tried the "Diff-amp-based delay element" simulation on ltspice but i couldn't get the results.Can anyone guide me what I did wrong while circuit design.

Please find the files - I have uploaded the original circuit and .asc file in the folder Files > Temp

Schematic file Name - Diff-amp-based delay element.asc
Original Circuit Name - Diff-amp-based delay element.jpg


Please help me on this and do the needful.



Thanks and Regards,
Dinesh

Hi dinesh.
May help link:

There is this:
IBM 0.50 micron (5HP, 5AM, 5DM, 5PA)
IBM 0.35 micron (5HPE, 5PAe)
IBM 0.25 micron (6HP, 6DM, 6RF)
IBM 0.18 micron (7RF, 7RFSOI, 7WL, 7SF, 7HP)
IBM 0.13 micron (8RF-LM, 8RF-DM, 8HP, 8WL)
IBM 90 nanometer (9SF, 9LP, 9RF)
IBM 65 nanometer (10SF, lOLPe/lORFe)
IBM 45 nanometer (12SOI)
IBM 32 nanometer (32SOI)
TSMC 0.18 micron
TSMC 0.25 micron
TSMC 0.35 micron
Bordoynov

20.09.2011, 13:00, "dinesh" <dinsul1986@...>:

--- In LTspice@..., Tan Micheline Tambayong <micheline.tambayong@...> wrote:

Hi,
thanks so much for helping me solving the problem.. But both
solution (adding Roff and changing the ground position)
are giving different results.
So I wonder which one should I use.

Also Tony, can you please explain to me what's actually
Roff do in the diode?

Thanks so much everyone..

Kind regards,
Micheline

Hello Micheline,

The result of both solutions is the same.
Please take a look to the enhanced version.

Files > Temp > Pefficiency_analysis-1_abc.asc

You have to plot the voltage difference V(a,b) at the output
and not the single signal V(a).

Best regards,
Helmut

Can anyone tell me where can I find the file "tsmc90.lib"

Thank you.

--- In LTspice@..., "Joe Walsh" <smknjoe@...> wrote:

Hi all,

Just joined this group a few days ago and I'm quite surprised at the level of traffic on this list.

I've been a VLSI design engineer for 21 years and am currently using Cadence tools (Virtuoso, etc), but have used Mentor Graphics in times past as well as Daisy systems in the very beginning. I now need to get a lot of BSIM3V3 models brought in so I can "play" on LTSpice.

I have used the Field Update Tool recently to make sure my LTSpice has the latest and greatest, but, the help seems very outdated. Case in point: Special Functions. The help says that the standard logic gates are available plus a VARISTOR and a MODULATE. However, when I go to place a symbol in the schematic, it shows that there are SRFLOP, PHIDET, BUF, and BUF1 available too.

Does anybody know (or can check their version of the tool) to see if the help has been updated to at least mention these newer components? I'm imagining that they have been there for awhile now and didn't recently appear after I ran the FUT.

Regards,
Joe

Hello Joe,

You always have the latest Help-file when you update LTspice
or when you install the latest version, but simply not
everything is in the help pages.

analogspiceman has started a wiki with info especially about
these non-documented features.



Best regards,
Helmut

--- In LTspice@..., "Apparajan" <dg1@...> wrote:

How do you measure frequency of an oscillator accurately in
LTspice..( I probably need this for .disto to work well)
cheers
AG

Hello AG,

You could make an FFT of the signal or you use .MEASURE commands.

Please take a look to the examples.

Files > Tut > MEASURE > TRAN

Best regards,
Helmut

--- In LTspice@..., "desmond00036" <desmond00036@...> wrote:

Hi, I am confused how do I get the AC voltage source with
the sine symbol as shown on the left side.

I tried plotting myself on the right side but no matter
how I try I was not able to make out the same thing.

I see that it is done in transient mode, and even if I
change to AC analysis under simulation command I am
still unable to get the same pattern.


Would be glad to have some enlightement here.

Regards,

Desmond

Hello Desmond,

This SINE-symbol is available in the LTspice component's
selection.

F2
[Misc]
signal

Best regards,
Helmut

Nope im referring to the "symbol" of the voltage source located in the left diagram not the results...
*note that there is a sine wave in the symbol itself..

The symbol is just a symbol ... an icon. You can draw it any way you
want. It makes no difference whatsoever to the simulation.

You could go into the symbol editor and change it to anything you like.

That is apparently what someone else did, for the picture you saw.

Andy

It looks like some body modified the symbol for a voltage source. If you control + right click on the voltage symbol you get the "Component Attribute Editor" dialog. In the upper left corner Click on the "Open Symbol" dialog. You can then modify the symbol. The drawing tools are pretty crude. But it looks like some body found a way to insert a symbol for a sine wave. After modifying a symbol click on "Save" in the "File" menu and you will then see your changes in the schematic.

Howard