LT Spice Tutorial: Custom Blocks / Parameterized Subcircuit Models

  • Posted on: 18 January 2015

In this tutorial, I'm going to introduce an extremely useful feature in LT Spice -- how to create a custom, parameterized part. I don't actually know what to call the resulting 'object' Maybe a block, a model, custom subcircuit, custom part -- I'm not sure.

The point is, you're going to have a custom circuit that you can create a simple symbol for, and then import and use with other circuits. Furthermore, instances of your custom model can have per-instance parameters!

For our example, we're going to create a simple model for a low pass circuit. We'll be able to import this block into other circuits, but each can have its own 3 dB roll-off frequency.

To start, we have to draw the model...

Drawing the model circuit.

Parameter Sweep in LTSpice using the .PARAM directive

  • Posted on: 6 September 2014

In this video, I demonstrate an example of performing a parameteric sweep in LTSpice.

As can be seen in the video, a combination of LTSpice's .PARAM directive and .STEP directive can be used to generate a series of simulations -- each one corresponding to a different value for a particular component value or other parameter.

In this particular example, we'll vary the value of a capacitor to alter the respone of an active low-pass filter.


Running LT Spice under Linux (Ubuntu) with Wine

  • Posted on: 17 August 2014

I used to use Linear Technology's LT Spice quite often, but I haven't used it much since my semi-permanent and complete switch to Linux. I thought I'd try to install LT Spice under wine -- it turns out, it works pretty well!

For the record, I installed Wine 4.21q under Linux Lubuntu 14.04. The video of the installation is shown below, followed by me fumbling my way through an Op Amp circuit -- hey, it's been a while.