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Hello ... I need a BV source to use a TABLE to look up a response. This works if the controlling variable is a .param ( Static for the full sim) but I need the BV to be dynamic ( Use the TABLE lookup in response to a changing voltage and respond with the voltage result ) I have tried to do this, but no success yet. I uploaded LTspice_TableTest.zip to the temp folder. Thank you so very much for any help you can provide!! JD

Thanks for your help!

I am trying to work out some old schematic and circuit issues and am looking for a model for the old LM121 opamp. Anyone have such a thing? I found the LM118, as I can use the LTSpice LT118A model. Now for the front end.

Hello, I have a YIG device which has two inputs. Tune input at 2V puts my YIG to 9.4Ghz and 10dBm FM input is current input which moves the output 100Mhz each mili ampere. I can measure the transfer function as a table also to see the effect of each input on the output Is there some bahvior model in LTspice which could help me represent this device in simulation? Thanks.

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 I have LTspice XVII installed in the directory: C:Program files\LTC\LTspice XVII Is it safe to install LTspice 24? so that I keep my old Auto_Genrated models? Can you please advise? is the new LTspice 24 any better ? Regards, Suded

Hello to the community, I'm very interested by the "PTC Thermistors Physical model" found in /g/LTspice/files/z_yahoo/Lib/PTC%20Thermistors/Physical%20model and I have two questions about it. 1) When I try to simulate the example ptc_veijola2.asc it throw me several errors: LTspice 24.0.12 for Windows Circuit: * C:\users\pascal\xxx\ptc_veijola2.asc Start Time: Sat Mar 15 18:34:27 2025 Questionable use of curly braces in "begb 0 egb i={1/(1/{emax}+0.5*(1+tanh((v(tptc)-{ts})/{c})))}" Error: undefined symbol in: "1/(1/(emax)+0.5*(1+tanh(([v](tptc)-(ts))/(c))))" solver = Alternate Maximum thread count: 8 tnom = 27 temp = 27 method = modified trap ERROR: Node U1:N003 is floating and connected to current source B:U1:V Total elapsed time: 0.575 seconds. Can you help me with that ? 2) I would want to simulate this PTC to "measure" a MOSFET case's temperature. In my case the mosfet have an extra pin that output a voltage proportional to case's temperature. The above PTC model take the ambient temperature and have a third pin to reflect internal temperature. Is it possible to add an extra pin to be linked to the mosfet temperature pin ? Thanks a lot in advance, Pascal

Hello, I'd like to use the SOAtherm with an user defined MOSFET. Unfortunately, i can't get the relation between the DanTherm model and the manufacturer model. Example: FDB3632 DanTherm model: R6=2.42E-03 C6=1.21E-03 R5=2.95E-02 C5=6.20E-05 R4=2.03E-01 C4=2.69E-03 R3=2.34E-01 C3=3.21E-02 R2=5.94E-02 C2=1.81E-01 R1=2.47E-03 C1=8.25E-08 Manufacturer model: CTHERM1 TH 6 7.5e-3 CTHERM2 6 5 8.0e-3 CTHERM3 5 4 9.0e-3 CTHERM4 4 3 2.4e-2 CTHERM5 3 2 3.4e-2 CTHERM6 2 TL 6.5e-2 RTHERM1 TH 6 3.1e-4 RTHERM2 6 5 2.5e-3 RTHERM3 5 4 2.2e-2 RTHERM4 4 3 8.1e-2 RTHERM5 3 2 1.35e-1 RTHERM6 2 TL 1.5e-1 Does somebody know the relation between these values ? Thanks, Marc

after simulation, i do the following: e.g. on a resistor R1, holding alt button and hovering over the element R1 shows in the status bar "Left-click to plot R1 dissipation: ...". but doing so, does not add any plot. other than manually typing and adding the plot, is there a correct way for the same. or am i doing something wrong here? thanks.

Hi all, I'm working on a project that involves saturable transformer and when I try to model it in LTSpice, I can observe the saturation effects when there is sinusoidal voltage but I cannot really observe it when I supply pulsating DC voltage. Please find the LTSPICE files in here: /g/LTspice/files/Temp/SaturableTransformer.zip I went through all the information available on the internet and it helped me a lot. I am stuck with this since some time now. Can anyone please help me with it?

Looking for ideal fully differential amplifier spice model for XSPICE simulations. The one I have based on the XSPICE "gain" code model doesn't have any CMRR or care if outputs are swapped. Anything based on dependent sources would be good. * XSPICE Fully Differential OpAmp .subckt opamp inp inn outp outn in_offset=0 gain=300e3 out_offset=0 aint %vd(inp inn) %vd(outp outn) amp .model amp gain (in_offset='in_offset' gain='gain' out_offset='out_offset') .ends opamp The SE output OpAmp using the same structure works fine...

My file is AC_Coupling.asc and has text that has been made smaller than it was in older LTSpice versions. The weird part is some text is small but other text is normal. Using version 24.0.12.

I am still using version 24.0.11, and I am finding some problems with drawing a block diagram of a multi-stage circuit as a schematic. I know that LTspice isn't intended for that, but It's much simpler to use than some other drafting apps. The problems are: 1. I can't see the grid points. They have always been minute but now I can't see them at all. They used to be more visible on print-outs of schematics. 2. Drawing a wire with CTRL held down doesn't allow the wire to start and end off-grid. It's the same if I draw lines instead of wires. I can't find a 'Snap to grid' check box to untick. 3. Is there any way to change the dimensions of a rectangle after it is drawn? I guess not. Would it be better to use the symbol drafter? -- OOO - Own Opinions only If something is true: * as far as we know - it's science *for certain - it's mathematics *unquestionably - it's religion Virus-free.www.avg.com

hello members, i was looking for a tool which can provide alternate diode models that match approximately to a given diode model. unfortunately, i could not find any website or software. it would great if anyone shares any information in this regard. thanking you in advance.

I am having issue with simulating experia BUK7S1R0-40H PET LTspice model characteristics https://www.nexperia.com/product/BUK7S1R0-40H when simulating mosfet with exact same setup as it is in application note i get quite different results for example output characteristic or transfer characterisitc. Anyone know what could be the problem here ?

Hello, I would like to use the LMR51606 in LTSpice. I only found an encrypted PSpice library on TI. I've already uploaded the file (LMR51606.zip). Unfortunately, I can't import the file into LTSpice. Is there a way to use the model, or does anyone have one? Thank you.

I have many testjigs that import digitised datasheet characteristic curves. An example of this would be: .subckt IB_400u 1 2 3 4 R1 3 4 1G B1 1 2 I=table(V(3,4) .inc BC848B_Ic_Vce_400u.inc +) This is used with a G-source called IB_400u, which in this case is the Ic vs. Vce characteristic of a transistor, i.e.: XG1 C 0 C 0 IB_400u The file BC848B_Ic_Vce_400u.inc is a simple table: +, 0, 0 +, 0.033713692946058194, 0.0037373737373737337 +, 0.07139456405596434, 0.007119195585620269 +, 0.09937242651150191, 0.01031229370884544 +, 0.11993258152246877, 0.014095645315621533 etc. This has always worked since LTspiceIV. With 24.1.4, it no longer works. Apparently, the new syntax checker works line by line, therefore the line: B1 1 2 I=table(V(3,4) ..will fail due to unbalanced parentheses. There seems to be no workaround that I have yet been able to figure, as the .inc directive must appear at the start of a line. I have uploaded example schematic to illustrate this issue: OP_Characteristic_rounding. This issue seems to be related to the previously reported issue with nested .STEP directives of the form: .step param A 0 10 1 + param B list 1 2 5 10 ..where the 2nd line is failing with 24.1.x. Example schematic uploaded: LTspice_24.1_Step_problem. -- Regards, Tony

Brady Ridgway uploaded some files to the Temp folder, which are now inside "Fuzz_Face_+G.zip". But Brady forgot to send a message here. Brady, please READ the group's guidelines on its main webpage. After uploading something, it is crucial that you compose and send an actual message here to this group, telling us what you did. You forgot to do that. Everyone else, here is the file Description that Brady used with his uploaded files: I am a beginner. I have uploaded two circuits, both of the classic Fuzz Face, which differ mainly in the power supply. Apart from the LT1054 and its components, the circuits are, I believe, identical. Graphing the voltage in most of the circuit produces very similar results, with the losses in the LT1054 being the cause. However, the current through the final capacitor C1/C3 (unfortunately I haven't indexed the circuits the same way) is completely different, as is the voltage at 'Vout'. Would someone please explain what I am missing? Some of us here will remember the Fuzz Face. It is a guitar "fuzz" circuit. If I remember correctly, it simulates poorly in LTspice, suggesting that the circuit works differently than SPICE simulations suggest. Andy

I have a python program kicking off LTspice as a background windows process with the following command. process = await asyncio.create_subprocess_exec(LTSPICE_PATH, "-b", "-run", solverFlag, fpath, stdout=asyncio.subprocess.PIPE, stderr=asyncio.subprocess.PIPE) I am running this process on a server and when I run it as my user account everything works as expected. Now I need to have it run as a windows service which requires a service account. I set this up and tried running but I get messages that symbols are missing from the simulation. I figured maybe the .ini file in the service account's folder was missing the symbol and library search paths so I made sure to match the .ini file in my service account's AppData/Roaming folder to match the one on my account. Unfortunately this did not help. Does anyone know why running in batch mode as a service account it would fail to look in the search paths?

Hello, I'm not sure whether this is the right place to ask about the difference seen in tube amplifier's transient analysis between LTspice and ngspice. The tube amplifier was the topic of this thread a few weeks ago. Let me know whether I can ask here.... Thanks, Carlo.