Passing Parameters to Hierarchical Block in LTSPICE

There were a couple of questions on how to pass parameters to Hierarchical Blocks from main level schematic in LTSPICE. In fact, until recently, I was having troubles doing this. But solution is very simple and strait forward. Read more

Testing TL431 model performance

A couple of test bench schematics were created in order to evaluate TL431 model performance and make a comparison between suggested model and existing ones. Most of test benches correspond to ones described in the datasheet to take chip measurement data and can be used to tweak model parameters to datasheet numbers. TL431 datasheet was used as a reference. Read more

Accurate TL431 model development, analysis and evaluation

I used datasheet schematic to create a model for TL431. This is very similar to Helmut Sennewald’s approach and seems to be straight-forward way of developing model, while schematic is available and is not very complicated. However, schematic is just a starting point. Read more

Audio Total Harmonic Distortion Analyzer for LTSPICE, making THD vs. Amplitude and Frequency sweeps in LTSPICE

FFT capabilities integrated into LTSPICE simulator are nice and flexible. However, if you would like to evaluate frequency or amplitude dependence of distortions, you have to take these measurements point by point and then manually plot them.

I created an LTSPICE add-on to automate THD measurements and plot result in the form of THD vs. Amplitude and THD vs. Frequency graphs. Read more

Baxandall inspired tone control – response simulation

Here is an example of parametric sweep, showing one possible way of potentiometer and variable resistor simulation in LTSPICE. I will use commonly referenced tone control, originally suggested by James and modified by Baxandall to utilize active tone control scheme. Read more

Stepping Component and Model Parameters in LTSPICE

Stepping component and model parameters is essential for many SPICE simulations. Some SPICE simulation programs are offering better capabilities than the other. Read more

Subsircuit analisys, converting subcircuit netlist to schematic

Imagine, you are lucky to get subcircuit for component you’d like to simulate. How good this subcircuit is?

Quality of simulation strongly depends on quality of subcircuit model that is used. Unfortunately, netlist for complicated subcircuit does not look like schematic drawing and is hard to interpret. Yes, everything is there, but as many design engineers, I’m thinking in terms of schematic when it is comes to necessity of interpreting functional behavior. Read more

Hierarchical Blocks in LTSPICE

LTSPICE is offering very nice possibility to incorporate repeatable portions of schematic into simulation, that is not available in many other SPICE simulation programs- hierarchical blocks. Hierarchical blocks represent reusable portions of schematic, visible on higher level of schematic as a symbol. While LTSPICE is missing multipage schematic editor, hierarchical blocks are offering another simple way of creating complex schematics. Read more

Schematic Integration of Subcircuit into LTSPICE

LTSPICE is offering very simple and straight forward way to create a symbol and  connect it to subcircuit definition.

Every subcircuit that you want to use should have corresponding schematic symbol. Symbol is a drawing, used to represent a device, described by a subcircuit or a hierarchical block. You may use existing symbol if it’s pinout and functional drawing corresponds to your subcircuit, or you may create a new drawing to represent unique subcircuit definition that you just created. Read more

Subcircuits in LTSPICE

Your simulation is as good as quality of the models you are using!

At least it is no better than that. This is the reason why I would like to dig into LTSPICE Subcircuit topic and create a simple reference. I’m using it myself and hope it will save you some time also. Though, there is nothing new in this tutorial and most information is just recollection of different parts of LTSPICE and SPICE3 documentation. Read more

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