ADDMODEL crashes in dual BJT MMDT3906

[whatever-a]

Hi there - I want to run a simulation using a dual PNP device, MMDT3906. I have created a library for this device. Unfortunately, Eagle crashes during ADDMODEL when I attempt to map the device to the manufacturer's spice file.

The manufacturer's spice file (downloaded from https://www.diodes.com/part/view/MMDT3906) works just fine if I add it to a single PNP device.

Has anyone faced the same issue when modeling dual devices? Is there a solution or workaround, besides modeling the dual device as two discrete components (which DOES work, but would affect my board)?

To reproduce the issue,

1. Download the attached zip which has the LBR and MDL files (the latter is just a rename of the .txt file from Diodes.com)
2. Open the LBR and pull up the MMDT3906 device
3. ADDMODEL, and attempt to map to the MDL file
4. You get as far as the screenshot below, but when you press OK, Eagle crashes.

[jorge_garcia · Accepted solution]

Hi @whatever-a,

I have reported the crash to our devs, because EAGLE shouldn't crash because of this. With that said there are a few things you need to do differently to be able to use the model. First off, whenever you have multi-gated part you have to make multiple instances of the model, one for each transistor in this case. EAGLE ships with an example of how this is done. See the mapgates example under Examples > ngspices > Analog.

We are planning to make improvements that will streamline this process that way you don't have to handle any of this manually.

Check out the example and let me know if you have any questions.

Best Regards,

[whatever-a]

Thanks, Jorge! I got it working, following the advice in the related post here: https://forums.autodesk.com/t5/eagle-forum/new-spice-models-for-multidevice-ics-lm324-2902/m-p/84870...

I did discover, however, that both gates of my device needed to be present on the schematic, AND I needed to MAP both of the gates at the same time, in order for it to work.

Thanks again -