LTSpice is a version of SPICE from Linear Technology

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LTspice: Noise simulation AND AC analysis in one plot

Is it possible to run a noise simulation and an AC simulation independently from one another and display the results in the same plot? Or better, is there a way to determine the SNR in one single ...
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asymmetric supply voltage for an OP AMP

I'm trying to amplify a signal with the bandwith of 500Hz - 10Khz, to do that I'm the circuit in LTspice using an asymmetric supply for the OP : the resistance R5 is just to keep things ...
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35 views

Stepped Sine Wave in Spice

I'm interested in simulating a circuit using a stepped sine wave input. I want to sample a sine wave at regular intervals and have the output constant during each interval, making an output that looks ...
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87 views

Are the stock transistor models in LTspice accurate at RF?

Just checking, I'm doing some experimenting of small signal RF design in LTspice.
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59 views

Creating an adjustable output regulator, in LTspice

Firstly, I'm having some trouble with simulating a variable resistor in LTspice.. I am wondering if this can be done? Also, does anyone have any advice on how to theoretically analyse this circuit? I ...
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45 views

How to use .step param with more than two parameters in LTSpiceIV

I need to do three transient simulations with different values of certain resistors (conveniently called R1 and R2) in each. What I mean to do exactly is this: Sim. 1: R1 = 1 k\$\Omega\$, R2 = 10 ...
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85 views

Designing a Filter

I am trying to design a filter which has the following Bode plot, So according to this site I designed the filter as shown below, As the two cross over frequencies are f1 = 50 Hz and f2 = 200 ...
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90 views

How to design a SPICE model from data sheet?

I am new to SPICE simulation and I am looking for spice model file of LTC 1065 data sheet can be found here here. I searched a lot on Google but I could not find ...
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1answer
103 views

Is there a spice directive to export waveform data in LTspice?

http://www.linear.com/solutions/1815 The above web-page explains how to export the waveform data to a text file. You basically run the LTspice simulation, clicking on the waveform window, go to ...
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19 views

How do I specify a parameter for a specific component in LTSpice?

I have a schematic which uses two center-tapped transformers. I found that I can specify the ratio between the two sides of the transformer by adding the directive ".param ratioT=0.3". Now that I ...
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1answer
152 views

Importing 3rd Party Models into LTSpice

I'm new to LTSpice but have the basics figured out (laying out a schematic, setting up simulation, running) and have done so with the basic but very well stocked library included. Of course my issue ...
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84 views

Cross-conducting half-bridge

I attached an LTspice schematic, a very simplified version of a MOSFET half-bridge driven by a push-pull isolated signal transformer. The FETs are cross-conducting, but their gate pulses are not ...
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66 views

Viewing netlist on native ltspice for mac

I have a mac os x 10.9.3 and I run the native ltspice on it. I cannot seem to access the netlist (the text file version of the schematic) on it. Looking at the website: ...
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137 views

Automate LT-SPICE?

I'm running a lot of simulations in LT-Spice, and I need someway to run them all either sequentially or at the same time. I was going to use Python, but I'm not entirely clear on how I would get ...
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1answer
72 views

Current sink - work in simulator, doesn't work in real

I've built current sink to drive wheatstone bridge. I've counted that I must reach current ~0.2mA to properly working whole measure system. Picture below present my current sink (I use MCP6001 op ...
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1answer
73 views

LTspice earthing information

In my simulation I require Earth on my chassis so that filter could be simulated. But I am not getting how to make an Earth in LTspice. Please note: This question is regarding ' LTspice ' ...
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81 views

Iron Core in LTSpice

I'm currently assembling a circuit in LTSpice which makes use of iron core transformers and inductors. There's only 1 type of inductor in LTSpice, which is also used to make the transformer. I would ...
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47 views

How to comment at the end of a command in LTspice?

Commenting in a spice file is quite straightforward. Start a line with an * and the entire line is a comment. The first line is ...
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176 views

How to suppress current spikes in transistor feedback loop

I am trying to pulse a load with a small constant current pulse (2mA @ 500us). The load does unfortunately have an unknown capacitance in the range 10nF - 1uF, parallel with an unknown resistance ...
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94 views

How to create Spice / LTSpice repeatable damped sinusoid

Is there a more elegant and/or simpler method to model a repeating, damped sinusoid from SPICE or LTSpice rather than chaining the damped SINE sources in series? Below is a schematic and the ...
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79 views

Where is the text for the symbol stored in LTspice?

The following is an image of the symbol opamp.asy. I opened the same file using Notepad++ and have pasted the contents below: ...
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214 views

LTspice: How to convert .asc file to netlist?

Using LTspice I can create .asc files which contain the information about my circuit. Is there a way to convert this information to a netlist? I am looking for a ...
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3answers
727 views

Is there a portable alternative to LTspice? [closed]

I am constantly on the move and come across many computers to which I have access and which have some version of Windows installed. I was wondering if there's a portable alternative to LTspice (or if ...
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66 views

A good reference for modeling pmos transistors in LTspice?

I've been trying to learn how to use LTspice, and I'm attempting to create a model for a pFET I've been using/will use on a real board. However, since my specific transistor isn't already in ...
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80 views

Modeling transformer in Ltspice

I am trying to model a transformer of 1:100 ration in Ltspice, here is the picture of it The above circuit is stepping up the input voltage by 100 times but I see something strange which is when I ...
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129 views

LTSpice - Printing resultant parameters based on expressions

I'm designing a circuit but I'm computing the values of components based on a set of design values. For example, ...
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3answers
104 views

Voltage dip on MOSFET switchable current shunt

I have the following circuit built up in LTSpice which will be used to switch in different sense resistors for current measurements. The mAEn signal switches the M1 transistor on at t=10ms which ...
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251 views

How to model IR LED Diode in SPICE [duplicate]

How does one model an IR diode in SPICE? Specifically, the TIL38. Datasheet here: http://www.supermoduul.com/PDF/TIL38.pdf I get it that Is needs to be found - ...
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753 views

Simulating SMPS with ideal switch in LTSpice?

Yes, this in a portion of a homework assignment (hence the idealized and slightly asinine problem statement). Aside from solving the circuit (which I have done), I am supposed to simulate the ...
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187 views

Waveform generation with opamp

I need to design a circuit that generates the voltage waveform shown in the Figure 1 when an input voltage is applied as shown in Figure 2. Figure 1 and Figure 2 are in the second link below. Only ...
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2answers
189 views

Pseudo-Nmos inverter in LTSPICE

In LTSPICE, I've built a pseudo-NMOS inverter and I've got 2 tasks to do using it. 1) I've a initial guess for Wn value of NMOS. I start the simulation with this value however, I need to optimize it ...
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68 views

Bireciprocal lattice wave digital filter

I am trying to model a bireciprocal Cauer filter in LTspice but I don't get the expected results. More precisely, using \$\gamma = \frac{re(p_i)-1}{re(p_i)+1} \$ where \$re(p_i)\$ is the realpart of ...
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98 views

How to fit MAX941 macromodel to LTSpice “opamp2”?

I am new to adding models to LTSpice. I have successfully added OPA350 from TI, but with MAX941 from Maxim Integrated I get some errors due to the LTSpice "opamp2" model does not have the same amount ...
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95 views

Syntax error in LTspice

I researched online and came across a code given here for PWM source in LTSPICE. When I save this .asc and try to open the same, I get the following error: Aborting: Unknown schematic syntax: ...
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133 views

How to break components in SPICE?

I've been learning SPICE over the past few days, using the LTSPICE program. One thing that just escapes me, is how exactly do we know when a component's absolute maximum ratings have been exceeded? ...
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104 views

spice representation for mechanical problems

As a mechanical engineer, for my work, I need to compute some displacements which are represented as a summation of frequency dependent admittances on a structural system and I would like to use this ...
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263 views

Singular error when putting a current source in series with a capacitor (ngspice)

I am getting singular errors when I simulate a current source in series with a capacitor with the following .cir file: ...
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1answer
169 views

Digital simulation display

I am new in the field of electronic circuit simulation and the two articles i am reading from http://en.wikipedia.org/wiki/Electronic_circuit_simulation http://en.wikipedia.org/wiki/SPICE have ...
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Spice Simulation model for LTC201, 202, 202

I'm looking for a spice simulation model for the analog switches from LT LTC201-203. Have anyone an idea where I can find them, on the LT site I couldn't find them?
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107 views

Why does this parallel->series rewrite change my AC simulation results a little?

Here are two circuits I've simulated. Both have a current source of \$\sin(\omega t)\$ mA with \$\omega=1000\$. They should be equivalent but give different simulation results. Here are the ...
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1answer
259 views

LTSpice: Silicon diode substitution improves Schottky clamp simulation

I'm simulating this circuit in LTSpice: The input is a 1 Mhz square wave with 10 ns rise and fall times. Plotted are the input, output as well as transistor base voltage. Now here is what ...
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1k views

LTSpice, MAC97A8 TRIAC model, Vgs error

I'm having some difficulty getting LTSpice to like a TRIAC model. The specific error it throws is "Missing model definition for VGT-0.65". The trouble is that VGT is a subcircuit parameter, not a ...
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222 views

How to draw an impedance in LTSpice?

I can draw a resistance or conductance in LTSpice, but how can I draw an impedance component? I've seen them drawn as unfilled rectangles before. I've tried searching the component list for ...
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127 views

LTSpice simulation trouble

I'm simulating a passband amplifier (some 80 - 200 MHz) stage with two transistors. I'm using LTSpice. When I simulate the transfer function I get a maximum gain at a given frequency, let's say 100 ...
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106 views

Spice Convergence error (Won't simulate)

I'm a trying to simulate the following circuit and I cannot work out why it won't converge. It used to work, but when I added R10 in it stopped working. The error can be seen in the screenshot. ...
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138 views

LTspice: How to make a time-variant mutual inductance coefficient in transformer model

I would like to make a transformer model with a time-variant mutual inductance coefficient. Does it work at (K1 L1 L2 var)?
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184 views

Measured VS Ltspice Difference in P-Chan JFET Attenuator

The following circuit is a slow switching +-15V audio signal attenuator: Why are the measured voltages (shown in white boxes) so different from the SPICE values (shown in the graph)? Note that ...
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101 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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167 views

SPICE Model For Voltage Reference

Anyone aware where can I find SPICE models for MAX6126, MAX6250 etc? I searched a lot and could not find. If anyone knows, can you please share the link/file?
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397 views

Why is the output from this astable 555 the reverse of it's simulation?

The simulator in LTSpice looked OK ... so I moved to the breadboard with an LED (eventually replaced the LED with a buzzer) at pin 3. One more difference in the assembled circuit is the condenser at ...