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Questions tagged [spice]

A famous textual circuit simulator with a number of graphic front-ends. Please tag with the precise flavor used (e.g. Pspice, LTspice, ngspice, Multisim, Proteus, Qucs) whenever appropriate (e.g. syntax or debugging) because there are substantive differences between implementations.

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What's the function \$ f(V_G, V_S)\$ and \$f(V_D, V_D)\$ in Meyer's model?

current through each capacitor is computed as $$ I_{gs} = C \frac{dV_{gs}}{dt} \\ I_{gd} = C \frac{dV_{gd}}{dt}\\ I_{gb} = C \frac{dV_{gb}}{dt}\\ $$ The actual constant average value to be utilized in ...
kile's user avatar
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Why isn't this inverter based amplifier amplifying?

I was studying about CMOS inverter an amplifier for analog applications instead of its more well known application as a switch for digital circuits. For the following inverter based circuit : I think ...
Koustubh Jain's user avatar
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17 views

Cannot get correct output in PSpice with the Buck Converter PSpice Transient Model from TI

I obtained the LM76005-Q1 transient model from the Texas Instrument website and imported it to PSpice. The website also provides a Design Calculator software, so I basically use it to determine other ...
Duc Anh Vu Trinh's user avatar
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2 answers
61 views

Where do I need give my inputs to this three stage master slave flip flop?

In his paper on TSPC logic, professor Razavi talks about use of the following topology as a master slave flip flop However, I don't know where to give input to this circuit while trying to simulate ...
Koustubh Jain's user avatar
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24 views

Is this LTSpice simulation of arduino's command for relay corrrect?

Here is a LTspice simulation for based on the video Design Relay module PCB using Altium designer To me, it seems ok, but i am lacking of experiences. What is your opinion on this LTSpice simulation ...
alvaro562003's user avatar
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1 answer
65 views

LTspice sofware Zener diode model 3bdc missing [closed]

I cannot find any models for LTspice for Zener diode breakdown voltage of 3 V. I need Zener diode because I am trying to get simple voltage stabilizer and my load cannot handle more than 3 V. I cannot ...
hhsting's user avatar
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2 votes
1 answer
119 views

LTspice and ngspice simulation results differ by 5-6GHz

I simulated a basic CMOS inverter based 3 stage ring oscillator in both LTspice and ngspice, using the same model files (using NCSU's freepdk45 models (VTG slow slow corner)). I expected there to be ...
Koustubh Jain's user avatar
1 vote
2 answers
48 views

How to be sure that the SPICE simulation results are the exact results I will get when I build the circuit (especially an ASIC) in real?

I have been doing circuit simulation in HSPICE for research. The final stage of the research is to build an ASIC. The simulation results are often satisfactory. However, I am still in doubt if the ...
Wanderer's user avatar
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0 votes
1 answer
69 views

LTSpice Unknown SPICE device type "N" [closed]

I try to use the model for the BFR106 transistor in LTSpice, which I got from here https://www.infineon.com/cms/en/product/rf/rf-transistor/high-linearity-rf-transistors/bfr106/?tab=~%...
TheButterMineCutter's user avatar
1 vote
1 answer
97 views

OpAmp Offset Null Pins in LTSpice

I'm simulating the following circuit, where the Op Amp is an LM741: The LM741 is an 8-pin device, and this design calls for using 7 of them. From the datasheet, here are the pin connections: I have ...
Dan's user avatar
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0 answers
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How to solve the LTspice error "Questionable use of curly braces in xxx."?

When I set up the following circuit, I ran into a question about the use of braces({}) The following are error messages: Why can't the first V be recognized by LTspice, or is something else wrong?
wxss's user avatar
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2 answers
66 views

Varactor diode simulation behaving opposite than expected

I've been trying to learn about resonance circuits and filters and so forth, intending to try to build some kind of tunable filter or something. I'm running some simulations in KiCAD to help confirm/...
Erhannis's user avatar
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1 vote
2 answers
174 views

Building SPICE models of optocouplers

Looking through this answer about the 6N137 optocoupler I wonder where one can get all those paramaters like Is, Rs, N, various internal resistances, etc. that are used to simulate the optocoupler. I ...
LevGor's user avatar
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2 answers
117 views

Low-pass filter in SPICE [closed]

I have a simple question about a low-pass filter. Without a load I have a resonance effect. /!\ I forgot to delete a modification on the previous screenshot the 0.5 Ohms resistor after V1 that's my ...
SteveninJ's user avatar
2 votes
2 answers
360 views

Replacing MOS parasitic cap with external cap. Why does it differ from internal?

This is a circuit which has parasitic capacitors: ...
kile's user avatar
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1 vote
0 answers
95 views

How do you simulate a ferrite clamp in LT Spice?

Someone asked before how to get parameters for ferrite bead simulation. The same method doesn't really work for clamps because almost all of them don't give information about resistance. I began ...
Tony's user avatar
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3 votes
2 answers
351 views

How can I simulate a (simple) 555 circuit in KiCad?

I want to simulate a 555 circuit in KiCad, but quite failing to do so. I found a SPICE model here and included it in my model like this: My circuit looks like this: The transient simulation works. ...
Bart Friederichs's user avatar
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0 answers
78 views

How can I create phase shift (in degress) of analog filters in Pspice?

How can I create phase shift of filters in Pspice? (like red curve) also measure the delay at the output for a band pass filter created cascaded amplifiers.
Electronx's user avatar
  • 756
1 vote
1 answer
66 views

Understanding netlist IF statements

I`m reviewing this paper on how to do SPICE modelling for an FG transistor: https://digital-library.theiet.org/content/journals/10.1049/el.2011.0458 Inside there is a figure provided: I`m completely ...
starboy's user avatar
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0 answers
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TINA-TI - trouble with Digital-to-Analog Converter DAC161P997 Self-Powered Transmitter

I'm dealing with the DAC161P997 simulation on TINA-TI. Using the model from TI, the circuit appears to function correctly only if I leave out the capacitors on the pin. Here's the setup – Data ...
Morena Fabozzi's user avatar
2 votes
2 answers
191 views

Clipping of output waveforms in a push-pull amplifier circuit with op-amps, how to fix?

I don't know what the circuit is called; I found it in the suggested schematics of a Resolver to Digital Converter IC. The circuit is an amplifier circuit that has two push-pull amplifiers and a bunch ...
Srivatsen R's user avatar
2 votes
1 answer
97 views

How would I create an analog block function in LTSpice?

I'm trying to create a small-signal model of a PSFB converter in LTSpice. The blocks in red are what I am trying to create, essentially a multiplier block which computes various .PARAM parameters that ...
user353165's user avatar
1 vote
0 answers
768 views

How do I properly import a .lib description into a LTspice symbol?

I am trying to simulate the TI part TPS62808 in LTspice, Pspice for TI, and Tina TI. I managed to easily run the simulation in the latter two simulators, but the models were specifically made for them,...
Yordan Aleksandrov's user avatar
3 votes
2 answers
170 views

Wrong LTspice simulation results when circuit has a large common mode potential to ground node

I'm trying to simulate the effects of a common mode signal on an optically isolated analog input circuit. I was seeing terrible common mode rejection ratios no matter what changes I made, and ...
jms's user avatar
  • 8,661
5 votes
1 answer
278 views

Unable to simulate a diode in KiCad/NSpice

I have this very simple circuit in KiCad: I'm trying to simulate the current through the LED, but whatever I do (change voltage of BT1, change resistance of R1, change model of D1), nothing ever ...
PMF's user avatar
  • 692
0 votes
1 answer
164 views

LTspice - auto-transformer impedance ratio

Can you please clarify what formula is used by LTspice to calculate the auto-transformer impedance transfer ratio for the equivalent circuits below? Both circuits resonate on the same frequency. I ...
andrzej's user avatar
  • 13
1 vote
1 answer
68 views

Spice model for a heatsink/mounting hole/test-point/connector pin - devices with one or no connection points - using Altium simulator

I am setting up a simulation model in Altium with SPICE models and have no idea how to provide a model for a single connection device (connector pin, test-point) or a no-connection device like a ...
REPuzzle's user avatar
  • 145
5 votes
1 answer
402 views

Why doesn't my MOSFET work?

This is a circuit that will take any Vin > 5 (through a diode bridge against reverse connection) and buck convert it to 5 volts. But, there is some error related to PMOSFET when I try to simulate ...
İbrahim İpek's user avatar
2 votes
1 answer
111 views

VOM617AT SPICE model not working

I downloaded the VOM617AT (optocoupler) SPICE model from the following address: https://www.mouser.com/ProductDetail/Vishay-Semiconductors/VOM617AT?qs=9vrc9xEJKyxW%252B%2FlvaQ%252BSPg%3D%3D I am not ...
nmr's user avatar
  • 133
2 votes
1 answer
76 views

SPICE Error in LM5117 Model in Microcap-12

I am trying to simulate SNVA829 (constant current constant voltage) schematic given in the application report from TI. I downloaded the spice model from TI site and imported it to microcap. When I ...
nmr's user avatar
  • 133
1 vote
0 answers
182 views

Flyback converter simulation in LTspice: discrepancy between Switching model and Averaged Switch model

I´m trying to make a Averaged Switch Model of a flyback converter for transient and AC simulation in LTspice. I´m following the document "Advances in Averaged Switch Modeling and Simulation" ...
Luciano C's user avatar
1 vote
0 answers
75 views

Difference between Kelvin and Celsius in dynamic thermal behavior of MOSFETs

I am trying to understand the temperature behavior at the junction level and this Application Note "AN_201712_PL11_001" from Infineon describes the process. The problem is that I have a hard ...
i33SoDA's user avatar
  • 103
2 votes
1 answer
113 views

Incorrect KiCAD simulation

I am learning to simulate a voltage divider using SPICE in KiCAD. Here is the circuit I created for the simulation The simulation plot indicates that the voltage on the net connected to R1 is lower ...
InputBlackBoxOutput's user avatar
0 votes
0 answers
53 views

One of the nodes of a SPICE model is not explicitly used. What is this node connected to? (Trying to simulate VOM1271T)

I am using the following SPICE model. In the .SUBCKT VOM1271T, what is -out connected to? ...
Etwus's user avatar
  • 171
2 votes
1 answer
125 views

SPICE (Spectre) "ideal" capacitive divider behavior

I decided to look at this after seeing this post, although I think they're not the same so making a separate question. I wanted to check what would happen in SPICE (this happens to be Spectre) if I ...
Halleff's user avatar
  • 675
0 votes
2 answers
4k views

LM7805 in LTspice

How can I use the LM7805 regulator in LTspice? I know it's about importing the third party components, but I am not getting it. Can somebody help please?
Alex's user avatar
  • 1,498
1 vote
0 answers
163 views

MOSFET Switching losses using SIMETRIX

I want to calculate the switching losses of a SiC MOSFET from STMicroelectronics. The manufacturer provides Spice models that I have incorporated into the Simetrix simulator (I don't have PSpice). My ...
MerOz's user avatar
  • 21
0 votes
0 answers
107 views

Failed to calculate the DC point error in Altium Simulation

I'm new to simulations in Altium and I'm having a hard time diagnosing a simulation error. Hoping for some pointers. I've included images of the circuit and Altium output errors for references. The ...
RP07's user avatar
  • 11
1 vote
0 answers
73 views

How do I Rename a .301 file to add a component to Tina-ti?

I'm trying to import a model of an NE5534 to TINA-ti that I downloaded from the TI site. The file has the .301 extension. I'm not really sure how I can use this, because I need a .CIR, .LIB, .MOD, or ....
Eli Y's user avatar
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1 vote
0 answers
91 views

Pspice: FFT and distortion in output file does not coincide

I don't understand how Pspice calculate the distortion factor of a signal. I have this 1kHz output signal from an amplifier, and here is the FFT with 10 montecarlo simulation (zoomed): In the "...
Northumber's user avatar
2 votes
1 answer
309 views

Parameters for Varistor SPICE model

Can someone explain to me what the "limit" command in the following SPICE model of a Varistor means? Also, what are v(4) and v(8)? ...
Maximilian Binzler's user avatar
1 vote
1 answer
47 views

Spice Software Supports Parameterizing Sub Circuits?

I have Multisim and I can't figure out how to add value fields to my sub circuits or hierarchical blocks. Let's say I'm making a sub circuit that is simply a voltage divider... so I have two resistors ...
Amr Elkamash's user avatar
2 votes
1 answer
220 views

SPICE netlist standard?

Is there an official IEEE or other standard for SPICE netlists? I have tried to find one and not found it. My friends and I are interested in building parsers of netlist files as input. I understand ...
Justin JRTI's user avatar
0 votes
0 answers
485 views

Method to import encrypted spice models to micro-cap?

I've been struggling to get encrypted spice models to work in micro-cap (v12.2.0.5) Referring to Andy aka's response, there should be some way to achieve this. https://electronics.stackexchange.com/a/...
crypton's user avatar
  • 135
3 votes
2 answers
757 views

Is there a way to automatically bring up a plot in LTspice?

Other spice sims have graphical elements or instructions to bring up graphs when you run a simulation. I know you can click on various points in LT spice an bring up plots, is there a way to include ...
Voltage Spike's user avatar
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0 votes
1 answer
159 views

Spice Simulator Error: Why "Inductor loop" is bad?

(I now making a tutorial about basics of circuit technology. The below is not about a specific circuit but general theory) I have used Spice simulator many years and I know "Voltage and/or ...
MAS SEG's user avatar
5 votes
1 answer
279 views

Iterative diode voltage drop solution doesn't match SPICE simulation

I'm trying to work through an iterative solution for the forward voltage of a diode in series with a voltage source and a current limiting resistor. simulate this circuit – Schematic created ...
Polynomial's user avatar
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1 vote
1 answer
79 views

Is there any practical SPICE modeling of a DC behavior of a diode from its given limited specs?

I have a laser diode and its shared electrical data is limited comparing to other diode datasheets. It has a V-I curve below(dashed red one): And three other parameters: (Reverse saturation current ...
cm64's user avatar
  • 2,217
1 vote
1 answer
89 views

Spice convergence troubles on this soft-start relay circuit simulation

I'm experimenting with a soft-start relay simulation. The relay is triggered when the capacitor bank C2 is charged a certain amount shorting R4. I then simulate loading V_out with a sequence of ...
learnvst's user avatar
  • 1,341
0 votes
0 answers
233 views

Showing circuit error during SPICE simulation of 1N4007 diode

I am trying to simulate the following circuit using KiCAD (I currently have version 6.0): simulate this circuit – Schematic created using CircuitLab After making the above circuit in schematic ...
nikunj choubey's user avatar

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