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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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dc sweep convergence issue for cmos inverter

I am having some convergence issue with DC sweep for a CMOS inverter. To duplicate the exact issue, see the following log as well as the attached netlist files, together with modelcard.nmos and ...
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28 views

Howto debug ngspice error PPerror: syntax error during transient analysis

In an effort to better understand software and how my computer actually works I have been experimenting with simple electronic circuits. I am working up to having three two bit registers (A, B, C) ...
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29 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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3answers
90 views

Measuring transconductance of any circuit

May I know if the following transconductance measurement test circuit is correct because I am getting quite small Gm values ? I suspect that I need to use some derivative function because changing ...
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33 views

Add OpAmp subcircuit spice model to Altium

I want to add SPICE OpAmp model of Analog devices by .cir extension containing .SUBCKT information to Altium. I have it's schematic but I don't know how to add it's simulation file to it. I have ...
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2answers
81 views

How do I model a digital out in a circuit simulation?

I have a PIR: Panasonic NaPiOn AMN34112 that has a digital output. When it detects motion it outputs 4V and 100 uA max. I want to connect this output to a LED using one or more transistor amplifier ...
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25 views

How to Reconfigure a Current Sense Amplifier Pspice Model

I downloaded the .lib Spice library for the MAX4172 and imported it into OrCad, available from: https://www.maximintegrated.com/en/products/analog/amplifiers/MAX4172.html/tb_tab2 The library file ...
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1answer
53 views

Frequency dependent capacitor for AC sweep analysis in LTspice

I need to model a frequency dependent capacitor for AC sweep analysis in LTpsice. I see that it is possible for inductors with GLAPLACE component, but I don't find anything about capacitors. The value ...
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70 views

What is this spice model? Is it a level shifter? [closed]

Does anybody know what is this symbol in spice? I think this is something like Gate Drive or Level Shifter, but I want to know the exact part name or something like this part.
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82 views

Resistor between input and output for push-pull follower

I'm reading about push-pull output stages in The Art of Electronics, 3e. On page 107 he presents the following circuit: I'm confused about the function of the \$100\Omega\$ resistor used here. Below ...
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44 views

LTSpice display issue on osx [duplicate]

I'm knew to this site spice so please be gentle :) I've installed LTSpice (LTspice XVII for OS X, Build Oct 25 2018, 14:56:22 US Pacific) on a MacBook Pro running macOS High Sierra 10.13.6. When I ...
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63 views

Simulation discrepancy in Qucs with 2N3904 transistor

I've been testing out a few circuit simulation applications and ran into an unusual issue with Qucs and the 2N3904 transistor. For a simple NPN transistor circuit with load resistor \$R_L\$, base ...
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34 views

How to simulate memristor crossbar array in spice properly?

I am trying to simulate a memristor crossbar array. But I found the readout voltage is constant for 3x3 and 5x5. Theoretically, the readout voltage should decrease with crossbar size. I check the ...
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GF 22FDX - leakage during power rampup - run time issue

Hello, I was running power rampup simulations on GF22FDX to see leakage. I have used kernels (individual placables and not full macro). Its taking huge time to complete. It got killed after 1 day ...
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25 views

How to simulate a component hspice model in multisim

I'm trying to simulate TS5A22364 and they have hspice and ibis models, and CAD model .bxl in Multisim. Is it possible? I have tried to add the package model but I don't know how to add the .bxl model ...
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2answers
44 views

SPICE circuit to find AOL and noise gain of Transimpedance amplifier

In Chapter 10 of Art Kay's book "Operational Amplifier Noise", he gives a SPICE circuit (pp.179) that can be used to generate the noise gain, AOL, and current-to-voltage gain. Could anyone explain to ...
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51 views

A voltage-controlled electronic equivalent of an SPST switch using MOS/BJT/Diodes

In order to use a close equivalent to ideal SPST switch for basic circuit simulations, I had been using a four-terminal voltage-controlled switch available in Ltspice simulator with quite less rise ...
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38 views

Spice model search with advanced sorting functionality

Does anyone know of a search engine like Mouser/Digikey where you can narrow down parts based on voltage/package type/etc., but exclude all results without PSpice models? Unless I'm doing it all wrong,...
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1answer
67 views

spice transmission line error

I am trying to model a very lossy coax transmission line. As shown in the circuit, the top TL model includes the shield line; the bottom lumps the shield terms into the center conductor and looks more ...
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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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281 views

555 Timer IC Simulation in Eagle

I am currently designing a circuit in Autodesk Eagle which requires a 555 timer IC. The timer may be any 555 chip, such as an ne555, tlc555, or lm555, or even one of their 556 variants, but the lm555 ...
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639 views

How can I convert PSpice model into LTSpice Model?

I would need to simulate these two MOSFETs ino LTSPICE but I have the Spice Model IPW65R019C7 Its PSpice model its insiede Nchannel CoolMos C7 https://www.infineon.com/cms/en/product/promopages/power-...
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141 views

How does SPICE calculate Drain current of a MOSFET model?

I am trying to use a MOSFET model for constructing transistor level circuits in ADS. (For instance, an amplifier). I saw that we could import transistor libraries from various locations (https://www....
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109 views

Why does a classic envelope detector produce a negative voltage for some periods, when high frequencies are put in?

I'm playing around in ngspice & trying to understand envelope detectors for ham radio. I'm pumping 150Mhz into the circuit described below - I'm expecting it to go positive in proportion to ...
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52 views

why does current flow thru a mosfet contrary to SPICE results

SPICE simulations with LTSPICE showed no current flows thru drain & source of an enhancement n-channel MOSFET with using its SPICE model - yet hooking up 5v 2A power supply across an actual device ...
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Understanding EOS SUBCKT behavior

I'm trying to modify an op amp to simulate its worst case behavior at end of life. In the common mode effect section of the LM124/NS I have the following ...
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1answer
140 views

LTspice error reading a downloaded model

I'm downloading a model for an n-channel MOSFET, the DMG6968U-7. This is the SPICE code: ...
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2answers
51 views

Impedance equivalent for oscillating switch in SPICE AC simulation

I would like to simulate this schematic in a SPICE AC analysis. A regular switch model only works in a transient simulation. Is there an equivalent impedance that I can use in the place of the ...
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1answer
48 views

How can I simulate limits of active components?

I am using LTSpice to simulate an energy harvesting circuit, so I am very careful with small leakage currents and losses. This circuit is all discretes (Diodes and FETS) and passives. Is there any way ...
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1answer
142 views

General Feedback Theorem - Spice model and loop gain

I am implementing the General Feedback Theorem (Prof. Middlebrook, 2006) in LTSpice, using the example given in the Spice folder. I used it to calculate the loop gain in a simple voltage follower ...
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1answer
70 views

Colpitts Osc. in ngspice: type of analysis and “singular matrix”?

I'm new to simulating circuits in spice (in this case, in the ngspice implementation in KiCad's nightly builds) and trying to build a simple Colpitts oscillator: I'd simply like to "power" the thing ...
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2answers
99 views

Inserting an unused voltage source in LTspice messes up transient results

This took me three days to figure out. Consider this simple circuit in LTspice: Looks pretty innocent. The output is a 1V sine wave, as expected. Going to View->FFT, setting number of data points to ...
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Visual circuit simulation on a Mac

I am currently trying to design a circuit on a Mac (some might say therein lies my problem). My goal is simply to design a rudimentary implementation of the circuit which I can visualise working I ...
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3answers
227 views

Hidden pins in CD4000.lib with LTspice

While working with the CD4000.lib in LTSpiceIV I came across the following: A capacitor was discharged via a CMOS Schmitt trigger input. Analysis of this behavior revealed that LTSpice may not handle ...
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SPICE issue: keeping subcircuits independent of eachother

TLDR I want to make circuits that are connected but independent in Spice. I am using the Xic graphical editor for WRspice, but I think that this issue isn't specific to the type of Spice being used. ...
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2answers
44 views

Errors in pin assignment for a SPICE file in Altium

I'm trying to simulate the following circuit in Altium before going to PCB route: But I get the following pin errors: I found the SPICE model and tried to assign them to this footprint: Here is ...
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118 views

Mextram Spice Model for Transistor

Where should I look for a Spice Mextram model for commercial transistors, such as the FMMT415? or Should I try a more advanced analog simulation software, incorporating Mextram or similar transistor ...
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53 views

Why is the output inverted for this SPICE model

I created a part from the SPICE code of a 4n32. I found the SPICE code from here. And here is the section about this part: ...
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86 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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31 views

SPICE model DC Sweep, triode region, factors other than Vto affecting knee slope (JFET or MOSFET)

In LTSpice, I'd like to 'soften' the 'knee' of the transition between triode and saturation curves. For a JFET, lowering Vto achieves this - but also affects the ratios of the VGS 'branch' voltages ...
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302 views

How can I simulate a Infineon IR2183 gate driver in LTspice?

I'm making a boost converter in LTspice, initially with ideal switches and comparators, but now trying to use realistic components. For the MOSEFT I just picked one from the available ones that has a ...
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258 views

spice: unknown parameter ($)

This spice file ...
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1answer
15 views

For Intrinsic cap calculation what should be time interval for integration of current?

I am trying to get VDD cap of SRAM memory macro. I am ramping VDD by 50mv in a specific time interval and then integrating the I(VDD) for the same time interval. For different time intervals like 50n,...
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36 views

How to fill in the fields in Diode_Sch in AHDL Cadence Virtuoso?

I want to have a diode with a current limit and a forward bias voltage of 0.7. I tried to fill the fields of the diode with data from its spice model but I got a totally different behavior in Cadence ...
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3answers
118 views

How to trigger a pulse until a capacitor fully discharges based on the output of a comparator

In my circuit I have a comparator which compares the output of a sine wave with a staircase wave, if the staircase is above the sine wave, I wish to use a Mosfet in its cut off mode which will allow ...
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59 views

Modelling microwave oven magnetron in SPICE

Just wandering if it is possible to model a microwave oven magnetron in terms of current / voltage waveforms at the input terminals in SPICE with any degree of accuracy?
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151 views

SPICE modelling output/input coupling in ultrasonic transducer driver

The real device is this. The LT SPICE model is here. The schematic of the driver part of the circuitry (omitting power supply circuitry and relay circuitry that basically switches the driver between ...
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1answer
60 views

Why does so much current flow into circuit?

The load is merely 2k yet voltage source provides ~3 amps to the circuit. I hope this isn't the case in reality because I want to build this. Simulations done in ltspice. Why so much current flowing ...
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160 views

Modelling catastrophic component failure

For most of the time in circuit simulation, the component models used are ideal and don't feature fail-states e.g. this answer here. Have there been any projects that have attempted to model what a ...
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Combining networks in SPICE - Iteration

Let us say you have two networks, A and B, that depend on each other. The voltages in circuit A influences the resistances in circuit B, and vice versa. The goal is to find a steady-state solution of ...