IBIS Pullup IV Curve

Pullup IV Curve

By Timothy Coyle

How to Generate the Pullup IV Curve

The Pullup IV curve table data has to be formatted to be Vcc relative according to the IBIS specification. (We’ll talk about this in a later article) So sometimes you will see the pullup IV curve shown ground relative and other times you will see it shown Vcc relative but it is the same IV curve just with a different reference point.

The Pullup IV Curve Sweep

The Pullup IV curve represents the drive strength of the buffer when driving high. The input of the buffer is set to logic high and a DC voltage source is placed on the output. The voltage is varied from –Vcc to 2*Vcc and the current is measured. The data is then compiled into the IBIS IV (current-voltage) table.

References and Links

“TI IBIS File Creation, Validation, and Distribution Process”, App Note SZZA034, 2002.

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