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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1answer
71 views

How to generate different noise in LTspice from run to run

I'm trying to simulate noise in my circuit, and ideally want to get a histogram of a certain parameter affected by that noise over many runs. However, when I use the white() command in LTspice, or ...
5
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1answer
105 views

Long-tailed pair - gain and bandwidth

I'm trying to understand this schematic of this differential probe: I marked some blocks. I have some questions about the block I marked "Long-tailed pair" (LTP). I have no experience with LTPs so ...
4
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1answer
291 views

How can I export the frequency response from LTSPICE without phase wrapping?

After I plotted the frequency response of a circuit using LTSpice as shown: I exported the plots data as a .txt file in order to plot them after that using MATLAB, however, after I plotted the data ...
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272 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 ...
3
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1answer
7k views

How can I model this common mode choke in circuit in LTspice?

How can the common mode choke in below diagram used in LTspice? By an inductor or transformer? How should be the circuit drawn in LTspice? I want to use this to filter out CM noises for single ended ...
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0answers
72 views

LT-Spice wont open file -> File limitations?

I am currently working on bulk simulations. For this I created a Python script which writes in the .asc files of LTspice and creates long tables, which are stepped through with the run variable. This ...
2
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1answer
59 views

How to simulate a simplified model of crosstalk effect in LTspice?

How can I make simple model and simulate the crosstalk between two adjacent channels of a multiplexed DAQ inputs? I observe that in its most exaggerated form, a nearly exact duplicate of one channel ...
2
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2answers
96 views

LTSpice: Get linear results using .meas command

Another quirky LTSpice question. I am measuring input impedance and using a .meas directive to get the impedance at specific frequencies: .MEAS AC Zi_freq1 FIND V(in)/I(v1) AT=10k When I right ...
2
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0answers
120 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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101 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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316 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 ...
2
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1answer
130 views

Power amplifier simulation and real time experiment mismatch problem

Thanks in advance to anyone who will take the time to read my first post here. At present, I am doing a simulation of a power amplifier in LTSPice. The schematic and relevant files are uploaded in a ...
2
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1answer
918 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: ...
2
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1answer
280 views

LTSPICE - Simulation Portability

Does anyone know of a comprehensive source of information on LTSPICE directories, libraries, the Control Panel - Sym & Lib Search, model locations, etc. as they relate to simulation portability? ...
2
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2answers
799 views

LTSpice: how do I pass to a function a component name as parameter?

Good morning all. I am implementing a subcircuit in LTspice, and I want also to modify the plot.defs to calculate some quantities with the voltages/currents inside the subcircuit. Thus, I will have a ...
2
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0answers
54 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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474 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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281 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 ...
2
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0answers
207 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 ...
2
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0answers
4k 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(...) ...
2
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2answers
465 views

Can I have two (or more) different symbols for the same LTspice schematic? How?

I have two components in my top-level schematic and noticed that the schematics of these components are actually the same. To avoid any duplication of changes done to these subcircuits, it would be ...
2
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0answers
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. ...
2
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0answers
443 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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0answers
440 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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0answers
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. ...
2
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1answer
174 views

LTSpice: Pass/Fail in Error Log if Voltage < Constant Reference

I am looking for a way to have LTSpice report a "Pass" or "Fail" ("1" or "0") in the error log if a measured voltage drops below a preset constant reference value. I have a model I made of a ...
2
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1answer
761 views

Modelling an RS-485 Bus

I am trying to model an RS-485 bus in LTSpice that consists of two power conductors and two data conductors within a single cable. The power conductors are twisted together and shielded, and the data ...
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48 views

Total harmonic distortion vs frequency

Is there a way to plot the variation of THD of a circuit due to a frequency sweep of the input signal? I use LTSpice. Cheers
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0answers
104 views

Why does LTspice have a hard time to simulate this?

update : when the two-transistor structure is replaced by a darlington model provided as spice model by the manufacturer, the gain dependence of stable waveforms disappeared. Now, without those gain ...
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0answers
37 views

Buck Converter - Calculating Line and Load Regulation

I have a buck converter with a PWM circuit and Control Circuit in LTSpice. I'm wondering, how do I simulate values for load regulation and line regulation? I was thinking for line regulation I could ...
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0answers
33 views

sallen-key bpf giving low gain after coupled to differential input

I designed a Sallen-key band pass filter where the gain at center frequency is 45.6dB. After feeding it with a sine wave at the center frequency, it amplifies the signal by 45.6dB. However, after ...
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0answers
23 views

How do determine MOSFET parameters in LTSPICE

I am designing a phase locked loop on LTspice (which I'm new to), but have come across a snag in the procedure: Is there a way to determine the output resistance of a mosfet (as the I'm not able to ...
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1answer
51 views

Diode N value less than 1 for temperature sweep

I have seen many manufactures using diodes N<1 for their PSpice model and LTSpice model diodes so I tried to run temperature sweep in LTSpice and PSpice In LTSpice if N<1 DC sweep eg:1m with ....
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59 views

Capacitor Storage Circuit Having Lower Voltage Than the Simulation

I designed a circuit to store a pulse of 8 volts and duration of 40 micro seconds. When I simulated the circuit it reached 3.5 volts and discharged.The circuit and the simulation is given below; In ...
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53 views

Clapp Oscillator Oscillating Frequency Strongly Dependent on the Transistor

For temperature sensing purposes, I have been challenging myself to design a dual mode crystal oscillator operating at the frequencies 30MHz and 90MHz (fundamental tone and the third overtone, ...
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2answers
127 views

Why is the cutoff frequency of this highpass filter with formula different from LTspice?

I used this online tool to play around and design a Sallen-Key low pass filter with a cutoff frequency of 0.3Hz. When I now put the resulting values for R1, R2, C1 and C2 in the formula I get exactly ...
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0answers
153 views

Error converting PSPICE model for LT Spice

I'm using LTspice XVII, and I'm having issues generating components from PSPICE component files. Previously, I was able to follow the method of opening the netlist file, highlighting the name, right ...
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0answers
67 views

opamp simulation

Is the following open loop transient simulation of opamp correct ?
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1answer
45 views

enveloping curve - LTPSICE

I have built a simple rlc circuit with a pulse input and performing transient analysis on it. I am interested in the voltage of the behavioral voltage source as shown in circuit. The system is an ...
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0answers
49 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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0answers
84 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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1answer
174 views

VCVS in LTSpice Operating as a Comparator

I am using a VCVS in LTSPICE. I am confused about the command in the Spiceline for using a Table. I want to use the VCVS as a 1 bit Comparator instead of making a transistor based one. What will ...
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0answers
318 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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0answers
160 views

Auto-numbering components in LTspice

I'd like to re-number the components of my LTspice simulation from left to right and top to bottom to make the schematic more presentable. For example, in the circuit below, I'd like R44 to be R1, R50 ...
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0answers
2k 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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0answers
309 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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0answers
174 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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1answer
96 views

Isolated three level pwm LTSPICE

I am doing a simulation on LTSpice of a three level ANPC. The ground is connected to the neutral point (i.e in the middle point of the DC input) and the gate drivers are isolated by using a DC DC ...
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1answer
428 views

Simulating ADL5536 Gain Block with Ideal Amplifier

I'm trying to simulate the ADL5536 Gain Block in LTspice. A link to the datasheet can be shown below: http://www.analog.com/media/en/technical-documentation/data-sheets/ADL5536.pdf Analog Devices ...
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0answers
118 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. ...