729 - IBIS Model: How do I find the output resistance of an I/O?
An IBIS Model is a mapping of voltage to current values for a given I/O standard, slew rate, and drive strength. User can estimate the output resistance by using a simple slope formula, in relative to the flow of current.
Using Ohm's law: Resistance = (delta Voltage)/(delta Current), user can create a graph in a spreadsheet program and visualize the change in resistance.
Lattice provides IBIS model for our devices. You may find the relative file in the product family landing page.
For example: MachXO5-NX device family
https://www.latticesemi.com/en/Products/FPGAandCPLD/MachXO5-NX
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