Creating simulatable components in Multisim 13.0 is easier than ever thanks to the enhancements to the Component Wizard. Specifically, the Component Wizard now checks the SPICE code of imported models, displays error messages and, my favorite improvement, features an intuitive way to configure the mapping information between symbol and model, which is a critical step in the component creation process. Let’s explore this feature.
For this example I will be using a SPICE model for the AD743opamp, which was downloaded from the Analog Devices website. After entering the symbol information and model data, the Component Wizard will ask for the symbol to model mapping; this information can be found in the SPICE model, as shown below:
* Node assignments
* non-inverting input
* | inverting input
* | | positive supply
* | | | negative supply
* | | | | output
* | | | | |
.SUBCKT AD743 1 2 99 50 37
* INPUT STAGE & POLE AT 65 MHz
IOS 1 2 DC 12.5E-12
CIN 1 2 20E-12
EOS 9 3 POLY(1) 16 31 100E-6 1
In Multisim 12 (and previous versions), the model nodes in the pin mapping table were selected by order (1, 2, 3, 4, 5), not by the name (1, 2, 99, 50, 37) they have in the SPICE model. This means users needed to open the SPICE model, locate the node names, and manually map them by order. The use of a table was recommended to make sure the mapping was accurate:
Here is screenshot of the pin mapping table in Multisim 12:
If the pin mapping table is incorrect, your custom component will not work, Multisim will display errors in the netlist or the simulation will output incorrect values.
In Multisim 13.0 we made things easier for you. Take a look of the following image:
Do you see the difference? Not only we have a display of the symbol and the model, but also the pin mapping table recognizes the node names. This means that you no longer have to open the SPICE model and manually map node name to node position; what you see in the SPICE model is what you get in the pin mapping table.
I’m sure this improvement will save you time and eliminate errors.