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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Help with voltage doubler in a WPT application

I need some help with this schematic to have higher voltage at Vrect. This is for charging a receiver at 25 mm in a WPT application. I was expecting a voltage of 2Vin at the output of the voltage ...
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Simulation of LM13700 in LTSpice

I'm trying to simulate a sample LM13700 circuit but it's not working for some reason. I need some help identifying why it isn't working. This is contents of the lm13700.sub file: ...
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Model positive exponential current curve on LTSPICE

I am trying to model the inrush current for a contactor. From the specifications I should get something like this: The hold current is 0.13A and the inrush current is 3.2A. This is controlled using R3 ...
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I'm trying to simulate an audio amplifier circuit but I couldn't find how to add LM386 to LTSpice like image. Is there any suggestions?

LTspice circuit. I couldn't find solution for this part of my simulation.
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If function error in LTSpice

Hi I am trying to simulate a model of a paper in LTSpice but I get an if function error which says "Syntax error: function if(): requires exactly three segments" These are the code of the ...
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Why is capacitor discharge time higher when an LED is included?

I'm testing the discharge time of a capacitor. I found that the time is higher when an LED is present. Circuit with a capacitance of 100mF, 10k resistance and 5V voltage. By calculating discharge ...
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LTspice error: Missing model definition

I have written the following simple curve tracer simulator: ...
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LTspice-RIAA-simulation not working out

I'm trying to simulate a RIAA-phonograph-preamp since I want to build a phono-preamp. I've built everything according to the data provided by LT for the LT1115. But my simulation seems to not be ...
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Falstad, Micro-Cap, LTspice

I've just started with Electronics and am enjoying the Falstad simulator for seeing how components work, current flows, etc; really great. I've become aware of Micro-Cap and was aware of LTspice as, ...
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LTspice Transient Analysis: Different parameters at different time points

I am trying to model a memristor using LTspice using the following subcircuit code. ...
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FinFET in LTSpice [duplicate]

I am trying to make an inverter using FinFET in LTSpice. I have a PTM file for a 20 nm FinFET. I created a symbol, circuit of the inverter and also include the file. But when I am running the program ...
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MPQ3904 LTSPICE Model

I'm trying to do some LTSPICE simulations using a MPQ3904 NPN BJT. Of course this specific model is not in the LTSPICE library. I tried to look up possible models online but I can't find anything. The ...
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Inconsistent behavior of MOSFET gate driver

I am working on a 7-level power micro-inverter which composed mainly by power MOSFETs. These logic-level MOSFETs (IRLZ24NS) are driven by separate photovoltaic gate drivers with integrated fast turn-...
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LTSpice: Stochastic Input Parameter in Subcircuit

I am trying to implement a subcircuit in LTSpice and I want the value of one input parameter to be a random value from a Gaussian distribution. However, LTspice is not recognizing the gauss() function ...
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I made a darlington transistor in LTspice. But, that has different values from theoretical values

As you may see from title, I made a darlington transistor like this. I set each transistor(Q1 and Q2) to have β = 150. So, total darlington β must have 22500 or thereabouts according to a formula ...
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In LTspice, why does having these two transformer models create an error?

I've run this circuit with all the inductors placed in the circuit with the appropriate 'K' commands and, although deeply slow in the simulation, it works just fine. When I've placed them into models ...
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LTSpice RL circuit simulation with ideal inductor and inductor from database

I am trying to simulate a simple RL circuit as shown below, the top one using inductor from the component library and the bottom one is picked from the database. Below is the properties of L1 ...
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How to input range of current values in LT Spice

Firstly, I'm a beginner at LT Spice. I wanted to learn how could you input a range of values for current. For example, let's say, I want my waveform to oscillate from 10uA to 10mA in the circuit below ...
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LTspice and op-amp strange behavior

I noticed a strange behavior using TL074 and I made this simplified block to verify my feeling. Opposite to what I see on a breadboard, I think the output(s) are totally wrong, but I cannot believe a ...
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LTspice AC Analysis extracting only the phase shift value at a certain frequency

I am trying to extract the phase shift value at a certain frequency in AC Analysis mode of LTspice. .meas AC Ph_Shift FIND (V(out)/V(in)) WHEN FREQ=50 With the ...
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LTspice JFET Voltage Divider Bias Configuration

I want to simulate this circuit in LTspice program and find Idss,Vp and Idsq,Vdsq but cannot. How can i simulate transfer characteristic?
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4 votes
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How can I model this power inductor more accurately? [closed]

I'm running some spice simulations in which I use power inductors. I found one on Aliexpress that seems suitable, but noticed that peak currents in the simulation exceed the rated saturation current ...
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How to simulate this circuit for common mode voltage effect?

Regarding my previous question and this paper, I wanted to simulate the circuit below to see whether it is rejecting common mode voltage as claimed. The paper says that sharing DAC's Vref with non-...
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How to control/remove "quiescent current" of UniversalOpamp2

In the circuit below, I get a quiescent current (entering positive supply and leaving negative supply of the op amp) of about 497 µA, while the load current is only 5 µA. I am aware that this ...
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Failed to find DC operating point for AC analysis LTspice

I finally successfully added the MCP 606 (MCP 609) in LTspiceXVII. I am now facing an error "Failed to find DC operating point for AC analysis". I have checked the maximum supply of MCP 606 ...
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LTspice voltage source definition as .param value

I want to have a bunch of .param directives to serve as test cases, one of which I will uncomment before doing a test. It allows me to make sure tests made in the ...
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Frequency plots LTspice not lining up with linear plot

When using the following circuit all the frequency plots I get are incorrect compared to the same frequency. What could be the cause of this? The internals of this circuit is an opamp and the output ...
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6 votes
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How to get the parameters of a ferrite bead

I have been simulating a ferrite bead on LTSPice, however, I so far have been using the LTSpice database to select the Ferrite bead, I now want to use a ferrite that is not on the database. However, ...
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4 votes
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Ferrite bead selection and simulations for a 2.4 GHz ESP32 3V3 power line

I want to be able to filter the 3V3 power line going out of the ESP32 MCU. Since this "may" have a frequency around 2.4GHz (Wifi or Bluetooth antenna). This may then affect other components ...
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5 votes
1 answer
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LTSpice voltage source understanding

I came across this Short Video on Youtube by MicroType Engineering, link here. His simulation on LTSpice was the below: I tried the simulation on LTSpice myself. However I am curious as to what the ...
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1 vote
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How to simulate LM2596-adj in LTspice?

I want to simulate the LM2596-adj on LT-spice. I have downloaded the models from the product page of texas instruments they don't work properly, because they are models for 3V3, 5V and 12 V output and ...
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How to improve a bandpass filter design

I want to design an active RC bandpass filter to filter out frequencies between 5MHz to 10MHz for a radiation detection circuit. I am using LTspice for the circuit simulation. I have used a cascade ...
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2 votes
3 answers
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Error in LTspice - Rser: Missing node(s)

I've been trying to simulate a central-tap transformer in LTspice. However, whenever I run a simulation an error message appears: "Rser: Missing node(s)" Could someone please explain to me ...
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Input bias incorrrect in stock LTspice model

I am trying to use the AD8067 in LTspice (v17.0.33.0). The model for this opamp ships with LTspice. I have rigged it up as a follower, and I am seeing 150pA input current. Per the datasheet it should ...
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How to add unit function u(t) - u(t-2) as voltage source in LTSpice?

As far as I know, we put the unit function as PULSE in LTSpice. If we have b.u(t) where b is a non zero integer, then we can put it in Von. But what if the function is u(t)-u(t-2)? And what if we want ...
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3 votes
1 answer
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LTSpice simulation with multiple comparators causing problems

I'm trying to build a circuit that limits the current flowing to the load at a specific level. To do this, I'm using a current sensing IC (INA138) and comparators to provide the necessary logic. ...
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LTSpice how to change background color plot OSX Mac Macbook?

How do I change the background color of the plot in LTSpice on OSX? There is no color setting when right clicking in the plot nor is there any settings in the "tab" of the program...
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1 vote
1 answer
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LTSpice change output voltage of gate

I am using the latest LTSpice on OSX (Mac). I have an AND gate which receives 10V for the in values X and Y respectively. The out signal is 1V despite the signals to the gate being 10V. How do I ...
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1 vote
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LTspice giving weird results in simulation of phase shifted full bridge converter

I am trying to simulate a phase shifted full bridge converter in LTspice. I had already simulated it in MATLAB Simulink and obtained the desired results, but I am redoing it in LTspice to include the ...
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Isolation detection circuit design

I came across the TIDA-01513 ref design by TI. The site is found over here. I have made a simulation of this design but I am not getting the desired results stated in the ref design. According to the ...
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Need help with simulation of three-phase active rectifier on LTSPICE

I have already successfully simulated a three-phase rectifier on simulink. However, I wish to implement the same on LTspice because I would have liked to see the effect of using non-ideal components. ...
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2 votes
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LTspice unknown subcircuit called OnSemi MOSFET

I have a problem with importing spice models from OnSemi. I have tried several interesting MOSFET libs from OnSemi, but I always get the same issue: I extract the lib and put the symbol and the lib ...
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2 votes
1 answer
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How to label waveform plots in LTspice under a .step directive?

I am using a .step directive to see the performance of a Miller integrator with various bypass resistors in the feedback path. The code and produced waveform are given below. However, I can't seem to ...
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What is the reason for the current spike in below simulation - at the end when cap voltage drops to zero?

Is the current spike at the end due to the constant power behavioral model? I have chosen an arbitrary MOSFET for the simulation. The initial current spike disappears when I add a series res to gate.
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3 votes
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Op-amp square wave to triangle wave converter not working as expected

A follow-up to a similar question from yesterday since the problem I've run into has differed enough to warrant something more than an edit. I have built an integrator to act as a 5V 32Hz square wave ...
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3 votes
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Op-amp output voltage offset

Hi i wanted to ask what causes an offset for the following integrator setup: I`m no sure if its the virtual ground or another fundamental reason im not aware about since the signal should always be ...
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L165 Power Op-amp LTspice model? [closed]

Added: I cleared my browser cache and the correct page popped up. Previously the link was just bringing me in a circle to the same LTspice group home page. I am looking for an LTspice model of the ...
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Generate a 120 degrees out of phase sine wave

I want to phase shift a sinusoidal by 120 degrees two times (in order to generate a 3 phase signal). I generated the first sine wave using an internal DAC. The sine wave is offset by 1.65V with a peak ...
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Problem with inductance meter

I'm trying to simulate a design I found for an inductance meter based on an LC tank and Arduino. To simulate this circuit, I put an amplitude for the current pulse of 40 mA, approximately the current ...
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4 votes
1 answer
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Op-Amp Voltage Follower not working at "extreme" voltages

I was testing the AD712 on LTSpice with a simple voltage follower. In a perfect world, I'd get this. Instead, I'm getting this. Now, I am aware that op-amps do not reach their V+ and V- voltage and ...
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