[sdiy] PCB layout rules

[Seb Francis]

Antti Huovilainen wrote:
> On Fri, 22 Dec 2006, Harry Bissell Jr wrote:
>
>   
>> One per IC power pin per voltage... so the tpyical
>> opamp gets two.
>>     
>
> Doesn't this mean that the ground might get contaminated by power supply 
> noise? From what I've understood, a cap is only needed between the rails 
> for stability.
>
>   

Isn't that the point of the cap that the ground doesn't get contaminated 
- the very fast current spikes are sourced/sinked from the capacitor not 
the ground trace.

But I guess the optimal place for the decoupling cap(s) really depends 
on the IC itself and where the current is flowing to/from.

Seb