Forum Discussion

Altera_Forum's avatar
Altera_Forum
Icon for Honored Contributor rankHonored Contributor
18 years ago

Altera device VI or IV curves?

I want to see VI or IV curves for the device outputs, and I keep seeing references to IBIS models. How do I use IBIS models to see VI curves?

2 Replies

  • Altera_Forum's avatar
    Altera_Forum
    Icon for Honored Contributor rankHonored Contributor
    18 years ago

    Hi desert rat..

    If you don't have access to a board simulation tool such as Hyperlynx, you can search the web for "IBIS Viewers". I have used a couple of different ones, they all behave about the same. I prefer the one from Mentor, it's very intuitive and I was up and running within minutes. When you create your VI curves for the pull-up (device driving high), use "Ground relative" instead of "VCC relative". The curves will be like you're used to seeing in data books. For the pull-up at ground relative, use the positive voltage, negative current quadrant. For the pull down, use the positive voltage, positive current quadrant.