Just a quick question about decoupling capacitors here, hopefully will be something nice and easy!
Let's say you are designing a circuit with 4 IC's that all need a decoupling capacitor. Some datasheets specify the minimum value of decoupling capacitor that should be on the PCB. Let's assume all of the datasheets to these IC's say a minimum of 100nF is required.
If all of the IC's are powered from the same rail, and each one has a decoupling capacitor of 100nF, will this not then mean they are in parallel, and hence lower the capacitance? With 4x 100nF capacitors, will this mean that each IC now has a decoupling capacirot of around 25nF value?
If a datasheet says their IC requires a minimum decoupling capacitance of 100nF, will there be any issues from this now?
As a visual aid:
simulate this circuit – Schematic created using CircuitLab
If we just ignore the function of the IC's and just focus on the input, we see all 4 are connected in parallel between V+ and GND, is this not the exact same configuration as this:
This, as we all know will give us a total capacitance of 25nF(ish). Am I right in thinking that this is how it would work? And are there any instances where this could cause issues?
Apologies for this question. As soon as I read the answer by Andy aka, I realised how silly it was! Must have been a long week this one!