If there is a resistance value on the output pad, how can you put down the resistances behind it? Wiring from pad to lead fram, pin/ball soldering, resistance on the board... not to mention about the capacitance
With the pad resistance, you still can do nothing
V = IR, if you know the pad supplied voltage and driving strength.... what do you guess next???
8)
As far as i know, the output pad impedance should match the impedance outside the chip to prevent signal reflection during high speed design. But usually the driving strength of IO pad (~12mA) is measured when VOL=0.4v or VOH=2.4v under DC condition. If you want to know the impedance of PMOS/NMOS inside IO pad, you must take a look at the IO pad layout to figure out the device dimension, then do some spice simulation to see what impedance it is.