In analog/digital
circuit, we always see capacitors being connected from supply pins to circuit ground,
but why?
From my
perspective, the two primary reasons for those caps are:
Reason #1:
Connection
from supply to IC has impedance - those caps (placed near the IC) will supply
most of fast current demand which gives less voltage fluctuation on supply pin
when supply current flows
Reason #2:
The supplies are not ideal, regardless of them being a battery or switch mode supply, there is
always internal impedance/resistance, and those capacitors will make sure the IC "see" low impedance supplies across the frequency of its bandwidth (remember that capacitor impedance drops as frequency increase)
Nice blog… Thanks for sharing very useful information about electrical circuits.
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