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Questions tagged [ltspice]

Anything related to LTSpice. LTspice is a SPICE simulation, schematic capture and waveform viewer program from Linear Technology. LTspice is freeware with very liberal license, it is lightweight and isn't crippled in any way.

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55 views

Correctly Using the Chan model in LTSpice

I am trying to use the Chan model to better simulate a transformer in my design. When I am making an equivalent transformer circuit, where does the Chan inductor go? On the LTWiki it is implied ...
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58 views

D-Class Amplifier Design Verification

I have an internship coming up working with comparators and amplifiers, so I wanted to take on a side project involving both of those components. Designing a D-Class amplifier seemed like a great way ...
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133 views

High Voltage Cascode with MOSFET LT Spice Simulation

I'm an electronics engineering student and want to develop a high voltage switch with normal Si N-MOSFETs. After some research, I discovered cascode switches for this application. Most of these ...
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49 views

Problem simulating LMP8645 current sense amplfiier in LTspice

Basically the problem i am getting is that the output offset voltage is extremely large (58mv) here is the datasheet for the amp: http://www.ti.com/lit/ds/symlink/lmp8645hv.pdf on page 9 it shows ...
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238 views

What's wrong with my input circuit? LTspice

I am designing my first power electronics board in LTspice to convert single phase AC to DC. This DC is fed to asymmetric bridge to drive an SR motor which is connected to a flywheel. This flywheel ...
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189 views

Nodal Analysis - solving 2 variables with 3 equations

There are three conditions: before the switch is closed (opened) while the switch is closed (closed) after the switch is closed (opened) I think I need to solve them sequentially, because the system ...
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3k views

Use variable in SPICE parameter list

I'm using LTSpice XVII to try and simulate a circuit. I've created a schematic which uses a Pulse voltage source to simulate a rotary encoder as follows: As you can see in the PULSE component, I'm ...
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2k views

LTspice, how to model a TLine

I am trying to do a simulation for a transmission line, I can draw below example circuit but got below two questions. How to do this step: .model TLine LTRA(...) ...
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2k views

Diode emission coefficient and saturation current

I have created a Zener diode model in LTSpice, and now I am trying to simulate it with different values of the saturation current (IS), emission coefficient (N) and breakdown voltage (BV) using Spice. ...
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395 views

Using SPICE to model dV/dt filter for inverter motor drives

I am starting to learn LTSPICE to create model where I can test various passive filter topologies for inverter drives where the output PWM has very short rise times and high switching frequency. I ...
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397 views

Spice code for uplim and dnlim?

Does anyone know where I can get sources for LTspice's uplim and dnlim? I'm trying to port a netlist from LTspice to ngspice. ...
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5k views

LTSpice Solar / photovoltaic simulation

I've been trying to simulate a solar cell with LTSpice to generate an I-V curve. The model I've been using is the simplified equivalent circuit model with a current source in parallel with a diode. ...
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49 views

opamp simulation

Is the following open loop transient simulation of opamp correct ?
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47 views

analogous mechanical electrical system- LTSPICE

I have created a basic series and parallel rlc circuit in LTPSICE. According to this http://lpsa.swarthmore.edu/Analogs/ElectricalMechanicalAnalogs.html and https://www.tutorialspoint.com/...
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43 views

How to convert maxim MAX9650 pspice file to LTspice compatible file?

I am trying to simulate the opamp MAX9650 in ltspice with the model provided here: https://www.maximintegrated.com/content/dam/files/design/tools/modeling-simulation/pspice/MAX9650.FAM I changed the ...
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29 views

LTspice - using save/load bias with a parameter sweep

I have a circuit which has some hard time converging in a DC simulation. The circuit does converge nicely in a transient simulation when skipping initial condition calculation. Therefore, I've ran ...
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150 views

In LTspice can I convert the units of an FFT which by default seem to be shown in dBV to dBµV?

In LTspice can I convert the units of an FFT which by default seem to be shown in dBV to dBµV? Cause of reason: The reason for this is that I've a modeled a LISN in LTspice where I want to simulate ...
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1k views

3-Phase Inverter simulation

I'm trying to simulate a 3-phase inverter for BLDC(PMSM) in LTSpice. The problem is that drain current is way too high and also phase voltage isn't right. **New image *One leg If I put one source(...
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204 views

LTspice simulation of AD8421 instrumentation amplifier giving incorrect output voltages

I am trying to run a simple simulation of an instrumentation amplifier (AD8421, model from here) running on a single supply, but the output does not seem to be correct. The screenshot below shows the ...
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500 views

Importing transistor spice model to LTSpice not working

Using LTSpice XVII. I want to import the Diodes Incorporated ZXTP19020DG model. The SPICE model from their web site is: ...
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117 views

Improve mosfet spice model for LT spice solver

I have a SI7460DP spice model that I would like to use in a DC DC buck\boost converter (LT8390). I'm using the standard LT spice file generated by LT powercad (boost converter going from 12 to 15V). ...
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307 views

Can the directory/path on the schematics be disabled for the print in LTspice?

When you print preview from LTspice schematics the program automatically adds path/directory of the file to the bottom of the pdf. Not really a question directly related to an electrical engineering ...
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86 views

LTspice Hung Up For Certain Voltages?

I am running a transient model of a Type-E PFN circuit (probably not an important detail) and my processing time jumps from about 1 minute for one DC source voltage to roughly 475 years for another. ...
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337 views

How's this for an SSR LTspice model?

I probably need to use an SSR for a design. I have never used SSRs, I just know things that have read on data sheets and the internet. I am planning on using the following spice circuit for a model... ...
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55 views

irritation in LTspice

I have written some measurement commands in LTSpice to calculate the weighted harmonic distortion (PWHD) .meas a1n INTEG (I(Lgra)*cos(2*n*180*fg*time)) .meas an PARAM a1n*2*fg .... (if somebody ...
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1k views

LTspice unicode trouble with micro symbol

I am having a pretty simple issue with LTspice, I built my circuit and it works fine, but the units for the capacitors don't display properly and I get the that "fE" unicode error I guess instead of ...
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123 views

Modelling a LED Array for SPICE simualtion

I am currently looking to model a whole LED array within LTSPICE. I am working on all of hte logistics right now. I currently have a LED array with about 300 LEDs on the array. Instead of modelling ...
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298 views

Precision absolute value circuits

I see several options for this; there is the TI's application bulletin (originally a Burr Brown App. Bull. from 1997) --- www.ti.com/lit/an/sboa068/sboa068.pdf There's LT's LT1001-based circuit: http:...
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283 views

Simulating varicap diode in LTSpice

I have been looking into making a voltage controlled oscillator using varicap diodes, however I have had hard time simulating the diodes in spice. Would anyone here have an idea how this would be ...
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79 views

Problem with Simulation Results VS Tested Results for a signal

For the circuit shown i am having some trouble wondering why my tested signal looks like this (i understand that it could be clipping) but when i measure my circuit in the simulation it is correct? ...
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116 views

How to interpret LTspice simulation outputs for improving dual channel boost converter design using LTC3788

I am working on a boost converter design using the LTC3788. I would like to take advantage of the dual output capabilities of this chip to produce 24 VDC at 4 amps on one output and 48 VDC at 2 amps ...
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2k views

MOSFET Parameters LTSpice

This is the LTSpice model of the Fairchild 2N7002 NMOS transistor. ...
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186 views

Best way to model noise in Current-to-Voltage Signal Amplifier Circuit

I'm working on a photomultiplier circuit shown below. When the photomultipliers are active, they produce a current signal, and the amplifier circuit converts that current signal into a voltage signal. ...
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172 views

LTSpice simulation :Unable to check the output values

I am new in LTSpice simulation .I have prepared the schematic of the following DC to DC buck converter design in folder i.e. C:\Program Files\LTC\LTspiceIV\Rough\ . My aim is to make a charger for a ...
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1k views

LTSpice: How to save output from multiple .op runs

So this is a somewhat complicated question... I am trying to run a .op simulation (DC operating point), using the .step command to iterate through a bunch of component values. I would like to save the ...
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70 views

Modelling transformer voltage drop in LTspice

I read that a transformer has a rated secondary voltage at a rated load current. So open-circuit voltage and any secondary voltage at different loads will be different. When modelling this in ...
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299 views

modelling of solar cell: offset in short-circuit current

I am trying to simulate the IV curve of a solar cell in reverse and forward bias. I have used bishop equation that you can see in the following picture. The mathermatical model is in good accordance ...
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296 views

Simple Interconnect circuit to simulate crosstalk in ltspice

I want to implement a very simple interconnect circuit to simulate crosstalk in ltspice because I am new to this area of crosstalk. Where can I find such a design? I have searched in the net but all ...
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1k views

Importing a verilog-a compact model in ltspice

I have a Verilog-A compact model, and would like to import it in LTSpice. I tried to google this, but to no avail unfortunately. Can anyone tell me how to do this if possible? By the way, in spectre ...
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624 views

Resonant circuit using LTSpice

I'm a college student and I was supposed to draw the Bode-plot of the following resonant circuit. I obtained this. My questions are: shouldn't I have obtained a bell-shaped curve? How can I find the ...
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142 views

What is wrong with this LTspiceIV model of a Deliyannis bandpass filter

I'm trying to analyze a Deliyannis bandpass filter at fc=7.15Mhz. I have constructed the following in LTspiceIV: which results in the following net list: ...
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140 views

boost and flyback converter

I am currently analysing this circuit But I ran into some problem since the boost component standalone raises the voltage to 40v the flyback is suppose to bring up the voltage to a further 540v ...
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354 views

Convergence problem in pspice but not in ltspice

I am trying to simulate a circuit in LTSPICE and it simulates without any convergence problems. However when I copy the netlist into pspice and try it simulate it I get strange results. It keeps ...
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753 views

LTSpice missing an SSR Component?

I want to simulate some circuits with SSR component but LTSpice does not provide this. From Eagle and KiCad I learned I can create my own component diagram. I'm not sure if I can do this also with a ...
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55 views

opamp constant-gm bias circuit

I try to incorporate the constant-gm bias circuit (Figure 6 in Improvements_in_biasing_and_compensation_of_CMOS_opamp) into the PFC (positive feedback frequency compensation) opamp, but it resulted in ...
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28 views

Estimate Phase Margin in Spice

I am trying to determine the phase margin of my design and I have come across two methods for modeling the open loop gain in spice. The problem is they are yielding slightly different results. I have ...
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34 views

LTSpice PWM Signal Showing Capacitor isn't Fully Discharged

I'd like to create a pwm signal input to mimic a real life situation of a pwm input that shows the capacitors aren't fully discharged. Please see the image below. I am currently able to create the pwm ...
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35 views

Time varying function on LTspice

I would like to create a variable resistor as shown in the attached pictures. How can I create this function? I saw the following tutorial, but I don't know hot to replicate my function (where some ...
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58 views

Using LTSPice to make Function Blocks for SIMULINK

I have a PLL that I want to model in Simulink using the control theory toolkit. I have the schematics for the PLL in LTSpice. Does anyone know of a way that I can integrate the spice model with my ...
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24 views

How to add thermal model on SOAtherm-Nmos block in LTspice

I would like to analyze the junction temperature of a SCT3022AL MOSFET during switching operation on LTspice. Followint the Spice model and the thermal model of the MOSFET: https://www.rohm.com/...