Routing Bulk Capacitor

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jayakrishnanj

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Friends,

Please check attached Scenario s of routing method for Bulk capacitor and

please let me know what will be pros and corns for the same

In our design Bulk capacitors were used Power input and in another design input to regulated supply.

Thanks,
Jay
 

Scenario 1 is better...because it takes power from directly to the plane and filter to ground. It has not any other hurdle between Power and GND.
 
definitely scenario1 is best for all capacitors. Most of the Bulk capacitors function is to sustain Lower frequency transients or charging lower valued capacitors near to IC. So, they don't require very efficient layout like this ( if you are doing space constrained design, give preference to other elements ). if you are using them as Buck(DC-DC converters) input capacitors then capacitors should be near and connected to VCC and GND with multiple vias to reduce connection inductnace.....
 
Hi,

1 is the best.

Just for information.
2 equals the series impedance for all capacitors. Every capacitor carries about the same HF ripple current.
But the quality is worse than 1

3 here the most right capacitor carries the most ripple current, because it has the lowest impedance to the load.
From right to left the series impedance increases and therefore the ripple current decreases. No good design.

Klaus
 
Definitely NOT 2 or 3, look at how far the path is to the planes compared to #1.
 
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