Without looking at the datasheet (lazy today), I'd say that 0.1uF cap is there for "decoupling" purposes. It is quite common to add such a capacitor between GND and Vcc (+5V) for each chip in a circuit, as close as possible to the GND/Vcc pins of the chip.

The purpose seems to be to smooth out any voltage fluctuations that might otherwise be caused by small instantaneous current draw as the chip switches internal states and whatnot.

https://learn.sparkfun.com/tutorials/capacitors/application-examples

So it's there just to keep the +5V supply "clean" and stable.

Cheers


Edited by mlord (24/12/2017 21:27)