'Loading' of a pin of an IC when running simulations?

[Yamin]

Hi guys,
Random question, but it's been something that I have been wondering for sometime.
I been trying to simulate the control circuitry for the 'mode' control function of the TDA8924 amplifier chip. I have to assume a value for the 'load' of that particular pin. In this case I use a 100K resistor. This is the only way to figure out what the voltage at the pin would be due to the external components.
So my question is that is there a certain value I should be using for this pin 'load'? Different values for different kind of pins?Maybe a hint given on the datasheet? I can think of other instances where I might encounter the same issue, with different ICs I mean.
Thanks in advance for the help