Hi, I have a LTSpice circuit simulation using three (3) SW switch models. The sim runs very slow and says: "Stepping Source 100% step size=8.99896e-05....." If I remove one of the SW models, the sim runs OK. Here's my netlist: R1 Vout_man V1 1k R2 Vauto N003 220k C1 N003 0 47n V1 5V 0 5V V2 /Vpor 0 5V V3 Vswitch 0 PWL(100m 0 100.001m 1 120m 1 120.001m 0 250m 0 250.001m 1 270m 1 270.001m 0 350m 0 350.001m 1 370m 1 370.001m 0) S1 N003 V1 Vswitch 0 MYSW XU2 /Vpor N001 Vauto Vout_man VCC 0 74HC10 VCC=5 SPEED=1.0 TRIPDT=1e-9 XU1 N002 V1 Vauto VCC 0 74HC132 VCC=5 SPEED=1.0 TRIPDT=1e-9 R3 N002 5V 10k R4 N001 5V 10k S2 N002 0 Vsw_auto 0 MYSW V4 Vsw_auto 0 PWL(180m 0 180.001m 1 190m 1 190.001m 0) S3 N001 0 Vsw_man 0 MYSW V5 Vsw_man 0 PWL(220m 0 220.001m 1 230m 1 230.001m 0) .tran 500m .include 74hc.lib .model MYSW SW(Ron=1 Roff=1Meg Vt=0.5 Vh=-.4) * Pulse(0 1 100m 1n 1n 20m 0 0) * PWL(100m 0 100.001m 1 120m 1 120.001m 0 250m 0 250.001m 1 270m 1 270.001m 0) * 31May2024: LTSpice Simulation of 8Bit-CPU AUTO/MAN Mode Select Pushbutton Circuit + Toggle Switches * PWL(350m 5 350.001m 0 370m 0 370.001m 5) * Note: 'MYSW' simulates the MODE Select Pushbutton.\nThis circuit also used for the RAM AUTO/MAN MODE Select pb.\nThe simulation shows the effects of:\n 1) multiple Mode Select pushbutton presses\n 2) effects of a /POR resetting or keeping the output in MANual mode. * Simulates Alternate Toggle PB ==> * MANual Toggle switch * AUTOmatic Toggle switch .backanno .end Q: Do I need to alter the default runtime parameters in order to get the three SW model sim to run? Thanks for any help or insight provided. Grant S.

I came across this site for sharing LTSpice models: https://youspice.com It seems pretty dated but has a model I'd like to look at, but I wasn't able to get the registration process to complete. Just wonder if anyone knows the status or has the ability to download a model for me? Thanks and 73, Bob W9RAN

Hello, Many thanks for your answers. Using "table" solved my "problem"; i uploaded a screenshot with my testing result. A last(?) question, how can i measure the resonant frequency precisely ? Regards, Rudi -- Cet e-mail a été vérifié par le logiciel antivirus d'AVG. www.avg.com

Hello, A dumb question: Is it possible to execute multiple .step commands each with one param or one .step with multiple param at the same time ? Thank you in advance for an answer. Rudi -- Cet e-mail a été vérifié par le logiciel antivirus d'AVG. www.avg.com

Greetings everyone, I need a 741 model or it could be another op amp that has offset correction pins, the need for these pins is because I'm making some circuits for teaching purposes, such as the full wave rectifier precision, these circuits are didactic and reinforcement in nature. grateful -- Carlos Delfino Quem sou: http://carlosdelfino.github.io/sobre_mim/ Keybase (PGP): http://keybase.io/CarlosDelfino ORCID: http://orcid.org/0000-0003-0385-264X Celular: (85) 985-205-490 (OI) - Aquiraz/CE “Para o Triunfo do Mal, só é preciso que os homens de bem não façam nada” - Edmund Burke “Ninguém comete erro maior do que não fazer nada porque só pode fazer um pouco” - Edmund Burke Conheça o Curso Maker (Arduino Minas): http://cursomaker.github.io Arvore dos Saberes/Tecnologia no Social: http://www.facebook.com.br/ArvoreDosSaberes

Hi everyone, is there any model for a Type D Flip Flop? I've been working with the dflop from LTspice library modifying his parameters, but now I would like to do some tests with a real model. I need a model FlipFlop with a propagation delay around 4ns, and frequency over 100 MHz. I couldn't find any LTspice model on some of manufacture's page like TI or ONSEMI, just IBIS files. Thanks.

Could someone tell me how can I model a SRD in LTspice and use that as a component in other circuits? I am new in LTspice and don't have much idea. I am attaching a link to a paper. https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=9223790&tag=1 I am trying to model SRD according to figure 1 based on equation (1) and then design circuits using SRD as component like figure 2 of the paper. Any help would be much appreciated.

Dear, am a beginner in LTSpice. I have an issue with Virtual ground and amplifying a signal. I am amplifying a 10mV signal that wors well. When i replace the power suppliers by a DC circuit, a splitter and a virtual ground, this is not working anymore. I guiess it is probably related to a virtual ground issue with LTspice but cannot fing online any solution. Many thanks for help. Bertrand

A simple J310 amlifier. When I added R4, even the value is 0R, the output voltage on R3 is 50mvpp. When I removed R4, the output voltage on R3 is only 5mvpp, same as the input voltage. It is strange. Could anyone tell me why? Thanks!

Group member Al Dutcher uploaded a file (PecoCMp.asc) but then he forgot to send any message about it. Al, please re-read the instructions on the group's main webpage, especially the part that tells you to always send a Message about what you uploaded. The Description attached to your file is: Heres a strange one thats making no sense Its a snippet from something that I m working on 120Vrms with a small ckt on the top If you use the diff prob, youll get ~4V across the res and BE junction from 3V source especially in fwd bias, huh?! The current is ok What am i doing wrong? Its in Temp What program did you use to simulate it? I used LTspice, and the simulated differential voltage V(N003,N001) = the voltage across R1 + the Vbe junction, alternates between 0 and 3.3 V. I saw no ~4 V. The source is a square wave with 3.3 V amplitude (not "3V" but close). So my question is, what were you looking at? Did you upload the wrong circuit? There are many problems with your circuit. The 120 Vrms source does nothing, so I don't know why you mentioned it. Andy

I can't tell if the problem with this voltage controlled oscillator is my circuit or LTspice itself. I'm using the current version (X64): 24.0.12. When I change the .tran length the behavior in LTspice changes, so maybe the experts here can figure it out. I just uploaded the file "Winer VCO.asc" for a voltage controlled oscillator. It charges a capacitor from a constant current source, then when the cap reaches 5 volts a comparator dumps the cap through a 555 timer to start charging again. For some reason when .tran is set for 1 full second it stops oscillating before 0.1 second. But with .tran at 0.1 second it oscillates all the way through. Changing the charging current at voltage source V3 also affects how long it runs before pooping out. If you probe the output of the comparator U2, it fades out slightly early at its final switch rather than switching off suddenly I can't see anything in my circuit that correlates with the time it starts to fade out.

Hello, I have in my lab an evaluation board for CGHV1A250F. It will be incorporated to the CGHV1A250F chip into a bigger design. Currently because its a Vds=45 and Ids=15 when rf is runnning then i see it as 3Ohm resistor. but the problem is that i need to pick a suitable gate driver so the capacitance on the gate will charge . how can i do basic " spice model" so i could put into a simulation? Thanks. https://pdf1.alldatasheetde.com/datasheet-pdf/download/1673867/WOLFSPEED/CGHV1A250F.html

Hello, I want to simulate the effect of UCC21220AD_TRANS floating ground in LTSPICE My gate drive needs to create floating voltage for irf7854pbf MOSFET. However i know that in LTSPICE floating ground is not possible. I have attached bellow all symbols and simulation file. How should make a floating ground in LTSPICE? Is it possible to create two different types of ground in LTSPICE? Thanks. https://groups.io/g/LTspice/files/Temp/john23/UCC21220AD_TRANS.asy https://groups.io/g/LTspice/files/Temp/john23/irf7854pbf_test.asy https://groups.io/g/LTspice/files/Temp/john23/UCC5304_Simplis_Test5.asc https://groups.io/g/LTspice/photo/294510/3786158?p=Created%2C%2C%2C20%2C2%2C0%2C0

Hi, I started studying a project using 4n25 to control a mosfet, but I was suggested to use the fda217, does anyone have a model of it that they can share? regards -- Carlos Delfino

Hi, : I have a question similar to the 'topic' of this thread. It's in the LTspice V.24 newer version with 'new fashion style icons for clicking' different than at least LTspice XVII V.17 which I was most time before used to play. The question is about the Lib/Sym path for searching which seems could be configured in 'Tools/Settings/Search Paths/', it works, but not supports 'recursive searching'. And without 'recursive searching', if users like me, who may build some classified/hierarchical folders under Lib/Syms main folders, that would be confusing trouble to load old saved .asc files for running simulation in new V.24 LTspice. May I ask. Is any easier way to solve this ? Thank you very much. Have a nice day.

Hello, I am trying to sweep frequencies to 20K with the behavioral voltage source using V=sin(pi*20e3*time^2). I get no error, yet I don't get the same results as I do using a wav file.

Hello I am trying to work with UCC5304 gate driver voltage.In the web site linkes shown below they say i can down load a simplis model. Is there a way i could convert it into LTSPICE? Thanks. https://www.ti.com/product/UCC5304#design-tools-simulation https://www.ti.com/lit/zip/slum722

I want to build spice models of high speed transimpedance amplifier. There are many op amps in LTspice simulation. However, I am looking for very high speed TIAs from other manufacturers. They have many but unfortunately there is no spice model. In that case, is it possible to make a spice model of the TIA from the scratch if they provide their datasheets? Thank you very much.

do LTspice have .Sens analysis (can perform the sensitivity analysis)?

Hello All, I have four PWL current sources that drive a half-dozen switches to simulate the outside world. The PWL current sources and switches push my simulation through its paces. I would like to parallel aditional current sources to switch certain functions on or off differently from the standard paces that the four original PWL current sources provide. All current sources are 0A or 1A and have 1 Ohm parallel resistors to cause a 0V or 1V output. For example, one current source runs on: pwl(0 0 48.2m 0 repeat forever (0 0 +20n 1 +11.99998m 1 +20n 0 +11.99998m 0) endrepeat) I would like to parallel an additional current source that, as simply as possible, runs on: IF(V(test)>0.5, 1, 0), probably a B source could be used here. In this way, the signal V(test) should shut down the PWL current source and at the same time fire up the continuous current source. What I can't figure out is how to get an externally controlled PWL current source that either does its PWL thing or zero output. Having to remove the four PWL strings to shut down the PWL current sources is too error prone. I tried to control the example PWL current source above, like this but, it does not work: if(V(test)<0.5, pwl(0 0 48.2m 0 repeat forever (0 0 +20n 1 +11.99998m 1 +20n 0 +11.99998m 0) endrepeat), pwl(0 0)) It produces the error "Missing current value for I1". I checked the help for behavioral sources and see no mention of PWL for a B source. Any ideas? Thank You