Stack Exchange Network

Stack Exchange network consists of 175 Q&A communities including Stack Overflow, the largest, most trusted online community for developers to learn, share their knowledge, and build their careers.

Visit Stack Exchange

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.

1
vote
2answers
65 views

If I need to find an MOSFET spice model with a particular length and width, where do I start?

I was using a 180nm NMOS and PMOS but now need to use an NMOS with about L=.36u and W=100u. I have two models but I dont think I can just change the length and width to any value. How can I check if ...
1
vote
2answers
86 views

SPICE BJT simulation results

I'm trying to simulate simple BJT circuits to verify my hand calculations. Following is my circuit, I'm just trying to get the calculated DC collector current with the shown voltages and parameters. ...
4
votes
3answers
1k views

Strange opamp's output impedance in spice

I'm simulating this circuit in Micro-Cap, which is the clipping stage of a guitar effect. The opamp model is the "NE-5532" I want to measure the input and the output impedance. I expected an output ...
0
votes
1answer
54 views

Voltage Multiplier Problem

I´m working on a voltage multiplier with 5 stage, i´m using the same capacitor and i think that my problem is the current load but i actually think that with a resistor in the output of the multiplier ...
0
votes
0answers
8 views

spectre save command - usage

I did look at save command documentation in Spectre user and reference guide. But it still looks confusing to me. I am specifically looking for commands to do following two task: 1) probe all nodes ...
0
votes
0answers
15 views

Transient Noise Analysis in HSPICE using Monte Carlo simulation while preserving process variation

I want to analyze the effect of noise on a simple transistor circuit using HSPICE, while maintaining process variation. The basic setup is as follows: The HSPICE models for the transistors are ...
0
votes
0answers
30 views

Performance issues when using CMOS SR Latch with 180nm transistor models in circuit simulator

I am trying to incorporate a CMOS SR latch made with 180nm Level +49 transistors into a larger circuit but am running into issues. I am hoping this community can point me in the right direction of ...
1
vote
1answer
69 views

How do I model a resistor array in SPICE?

I am currently building a library of SPICE simulation models that is going to include resistor arrays. These arrays exhibits both absolute tolerances and relative tolerances. Usually, the relative ...
1
vote
0answers
24 views

How to calculate or show in matlab/pspice the DC component from a circuit simulation?

Based on Pspice I'm simulating this RL full wave rectifier That gives the next voltage and current output at the showed probe point The idea is to extract the DC component of the current or voltage, ...
1
vote
2answers
68 views

Plot voltage for different resistor values in LTSpice

I've signed up for a SPICE course at work, that will take place on Monday and I'm desperately trying to learn electronics and SPICE. (I work as an embedded engineer but with very lacking electronics ...
0
votes
2answers
70 views

NMOS current flowing equally in both directions in SPICE simulation

I am trying to characterize this nmos on Xyce simulator (and trying to change its present Vthreshold) and am first DC sweeping the gate and measuring the current through the nmos. I run into this ...
0
votes
0answers
26 views

LTSPICE Model Parameters of P-MOSFET

I am trying to simulate a circuit including TSM500P02CX P-MOSFET. The manufacturer of the MOSFET doesn't provide SPICE Model, so ...
0
votes
1answer
37 views

Linear regulator operating point over input DC Sweep analysis

I'm sweeping the linear regulator input voltage on DC using Spice from 0V to maximum expected Vin. However, as the OTA that makes part of LDO is internally supplied by the output voltage, the ...
1
vote
2answers
39 views

Error in third-party SPICE subckt of a MOSFET

I am simulating my circuit having a DMG1012T N-Channel MOSFET in LTSPICE XVII. My Circuit is given below: However, after ...
0
votes
2answers
103 views

How to automatically “normalise” a voltage signal in LTspice?

I would like to create an output signal that is normalised by the maximum value of a signal in LTspice. This is to produce a signal between [-1, 1] that is suitable for producing a wave file like ...
1
vote
2answers
72 views

SparkFun Sound Detector Circuit Analysis

I would like to request some help in analyzing the op-amp circuit used by SparkFun here. I'm particularly interested in the pre-amplifier portion of this design. The write-up included by SparkFun ...
0
votes
0answers
36 views

TI Photodiode Trans impedance amplifier Circuit?

I am designing a Photodiode(Vishay/ current of 15uA) circuit amplifier (TI ) in SIMetrix. frequency of Photodiode is 1MHz. I choose an Amplifier from TI as OPA355_Q1(spice model imported from TI) and ...
0
votes
2answers
84 views

Colpitts values for NXP's SA605?

I'm trying to put together a simple superhet radio, receiving at 161.75MHz (this is for AIS reception.) I've been trying to design around NXP's SA605 chip (see SA605) but I'm having a hard time ...
1
vote
3answers
47 views

zero AC gain of CMOS inverter

Why is the following AC analysis of CMOS inverter resulted in zero AC gain (vout/vin) ?
1
vote
0answers
36 views

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 ...
0
votes
2answers
47 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) ...
1
vote
1answer
50 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 ...
2
votes
3answers
99 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 ...
1
vote
0answers
63 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 ...
0
votes
2answers
85 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 ...
0
votes
1answer
31 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 ...
1
vote
1answer
91 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 ...
0
votes
1answer
72 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.
0
votes
2answers
94 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 ...
0
votes
1answer
119 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 ...
0
votes
1answer
89 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 ...
0
votes
1answer
33 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 ...
0
votes
2answers
58 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 ...
0
votes
1answer
40 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,...
2
votes
1answer
87 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 ...
1
vote
0answers
128 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 ...
0
votes
1answer
514 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 ...
0
votes
2answers
2k 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-...
1
vote
2answers
244 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....
0
votes
1answer
128 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 ...
1
vote
1answer
56 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 ...
2
votes
2answers
28 views

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 ...
0
votes
1answer
184 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: ...
0
votes
2answers
58 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 ...
0
votes
1answer
51 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 ...
0
votes
1answer
160 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 ...
1
vote
1answer
95 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 ...
3
votes
2answers
111 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 ...
0
votes
0answers
127 views

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 ...
0
votes
3answers
339 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 ...