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using the TI model of LF356 on LTspice v24.1.0 result in strange behaviour, DC output from OpAmp is over 18V when the supply voltages are ± 15V.

In the "Component attribute editor" I've changed parameters for this version of LTspice, the original from the file area "LF356_test.zip" result in errors at simulation start.

I want to simulate a input circuit of an test equipment (Boonton 4200) that is oscillating at 93Hz square wave with amplitude near the supply coltages. I'm curious to see the Phase Margin of this differential stage with three LF356.

Clearly this pspice model is incompatible with this LTspice version, or there is a workaround possible to apply ?

I don't have version 24.1.0 installed, but with 24.1.5, the (Helmut's) original circuit stalled at 40% completion, but was correct up to that point. When I changed the rise and fall times of the source to 100n from 10n, it simulated perfectly. With version 25.0.12, the original unedited circuit had no problems. I also ran an input voltage sweep and saw the output clipped well inside the supply voltages.

The version 24.1.0 was quite short-lived because there were a number of problems with it. There have been many internal changes in the 24.1.x release. some of these have since been fixed, but others remain.

It may be that nobody can duplicate the problem you are having, but if you have changed anything in the schematic, you should upload it to Files > Temp, so more people can try. Did you change any of the Control Panel > SPICE settings from default? The Trtol parameter in 24.1 is different from 24.0 in the default state.

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Regards,
Tony

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We can't help much unless you let us see more of what you are doing. Upload your .ASC file AND all the other files required to run the simulation, but not .RAW? and .LOG files or pictures,? in a ZIP archive to Files => Temp.

Go to the web page: /g/LTspice/topics. Click on Files in the list on the left. Then click on Temp. Then click on New Upload in the blue box at top left. Click on Upload File in the drop-down menu. Then send a message to tell us that you did that.

Hi,

using the TI model of LF356 on LTspice v24.1.0 result in strange behaviour, DC output from OpAmp is over 18V when the supply voltages are +/- 15V.

In the "Component attribute editor" I've changed parameters for this version of LTspice, the original from the file area "LF356_test.zip" result in errors at simulation start.

I want to simulate a input circuit of an test equipment (Boonton 4200) that is oscillating at 93Hz square wave with amplitude near the supply coltages. I'm curious to see the Phase Margin of this differential stage with three LF356.

Clearly this pspice model is incompatible with this LTspice version, or there is a workaround possible to apply ?

Thanks, Stephano

Hi,

using the TI model of LF356 on LTspice v24.1.0 result in strange behaviour, DC output from OpAmp is over 18V when the supply voltages are +/- 15V.

In the "Component attribute editor" I've changed parameters for this version of LTspice, the original from the file area "LF356_test.zip" result in errors at simulation start.

I want to simulate a input circuit of an test equipment (Boonton 4200) that is oscillating at 93Hz square wave with amplitude near the supply coltages. I'm curious to see the Phase Margin of this differential stage with three LF356.

Clearly this pspice model is incompatible with this LTspice version, or there is a workaround possible to apply ?

Thanks, Stephano

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That's a bit too much freedom. LTspice will not warn you of duplicate designators until you run an analysis, which will obviously fail. If you leave it entirely to LTspice you will never get duplicates. Caution! This does not apply to net names.

The transfer function and time domain expressions look OK to me but the scope plot is obviously "wrong".
This could be caused by the sample-based Simulink implementation. What is the sample-rate / solver
algorithm? If there is aliasing all three representations could be correct.

-marcel

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Right-click on the number, such as R1. An editing pane opens where you can change it to anything you like, within reason.

Sorry for FAQ.

How can I renumber the parts number?

I heard "shift+ctrl+alt+R" is available.

But no change appear.

?

Hidehiko JA9MAT.

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Two ports, really?? I count three.

?

Add the Tune and FM inputs, to produce a single frequency-controlling voltage.? You have many ways to add signals, including a B-source.? You need to decide on the input resistance to use, for your Tune and FM ports.

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Then connect their sum, to the FM input of the MODULATE component.

?

Set it's Mark and Space parameters to have the right scale (1.2 GHz/V) and offset.? This is simple Algebra.? It's very basic.

?

Depending on what john23 is wanting to model, it might be necessary to actually model the TUNE and FM circuits. They are both connected to coils internally, so the inductances might need to be included, particularly if the YIG oscillator is in a frequency control loop or synthesiser. Typically, the TUNE coil will be 10s of mH and FM coil will be about 10uH. (They also normally have internal heaters too, with additional connections, but that has not been mentioned.)

Coo, this brings backs memories from the 1980s.

--
Regards,
Tony