a few days ago followed this blog Multisim told me he was looking to simulate the component LM386 audio amplifiers. This component is not included in the Multisim database, but if we can create SPICE model using the Component Wizard . I did a search on the Web and to locate a SPICE model for the LM386, it is noteworthy that the model is not guaranteed, but early tests have been successful. So then I share a tutorial on how to create this custom component in Multisim. If you want to see a more basic tutorial on creating components visit the article Creating Components in Multisim Basic.
The LM386 is a power amplifier for use in low voltage amplifiers typically used in AM-FM radio. The spec sheet can be downloaded here . SPICE model for the LM386 I found this discussion forum . Only copy the model to notepad and saved it with a. Txt. The following figure shows an excerpt of this model:
With the LM386 spec sheet and we now SPICE model Multisim in English and select the menu Tools รบ >> Components Wizard. In the first step we entered the overview of the component:
In step 2 we add the information ng footprint (footprint) for the component, this is necessary in case you later need to transfer the design to Ultiboard to create the PCB. For this, click on the button Select a trace. According to the spec sheet this component is available in several encapsulated in this case I selected the print M08A:
can now edit the symbol, you click on the Edit button to open the Symbol Editor in Multisim is very easy to use. I made a simple symbol:
Step 4. Assign terminal type (bidirectional, input, etc) to each pin:
We mapped the symbol terminals with the terminals of the mark:
Very important copy and paste the contents of the SPICE model for the LM386:
The next step is very critical and this is where most of the time they make mistakes. Here we map the nodes of the model with the terminal symbol. This information is usually at the beginning of the SPICE model. If we open the text file containing the model for the LM386 going to see that the configuration is one to one, for example, node 1 est mapped to the terminal to g1 (Gain 1), node 2 with the terminal inn (-Input), etc. There is not always the ideal case, so you should be cautious:
list, save the component in the User Database . We can even create a new Family :
To test I set up a typical application contained in the specification sheet. Is an amplifier with a gain of 20:
1mVp For an input of 500 Hz we have the following output:
I hope you have enjoyed this tutorial and find it helpful.
Greetings! Fernando
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