UG445 Datasheet, PDF (14/24 Pages) –

Thresholds
R
If you want to find out how much current an I/O can sink before you raise the voltage level
above Volmax, you can look at the Iol (output low current) curve in Figure 2, the Volmax
and trace to the corresponding current value.
In the example in Figure 2, if the Volmax is 0.5V, you can sink 21 mA.
UG445_02_052207
Figure 2: I/V Curve Example 2
Another common use of the I/V curve is to determine the voltage at the IOB depending on
the load.
For example, if you are driving a 24 mA load from CPLD, will you violate the input
thresholds?
14
www.xilinx.com
CPLD I/O User Guide
UG445 (v1.2) January 14, 2014