FreeLists / si-list / [SI-LIST] Re: Is Impedance Enough for Describing the PDS?

[Zhangkun <zhang_kun@xxxxxxxxxx>]

Dear steve

When you put all the decoupling capacitor into one corner of the board or 
distribute them, the impedance of PDS is not same. If I only consider power 
integrity, is impedance of PDS enough?

Best Regards

Zhangkun
2004.7.9
----- Original Message ----- 
From: "steve weir" <weirsp@xxxxxxxxxx>
To: <zhang_kun@xxxxxxxxxx>; <si-list@xxxxxxxxxxxxx>
Sent: Friday, July 09, 2004 8:33 AM
Subject: [SI-LIST] Re: Is Impedance Enough for Describing the PDS?


> Zhangkun,  the problem is that the PDS overlaps both signal integrity and 
> EMC compliance.  If the system rules are done right, then the PDS 
> decoupling problem will eventually reduce to an impedance profile.  But 
> that profile is both spatial and frequency dependent.  If I shove all the 
> decoupling capacitors into one corner of the board I get a very different 
> result than if I distribute them.
> 
> Steve.
> At 08:04 AM 7/9/2004 +0800, zhangkun 29902 wrote:
> >Dear all
> >
> >When talking about power delivery system with other engineer, there are a 
> >lot of element to describe the PDS, such as energy storage, decoupling, 
> >bypassing, and so on. I think all these parameter could be described by 
> >one element, impedance of PDS.
> >
> >Is my point right? Is impedance enough for describing the PDS?
> >
> >Best Regards
> >
> >Zhangkun
> >2004.7.9
> >
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