[SI-LIST] Re: RE：How can we get the resonance frequency and Q between
- From: Luping LIU <liewluping@xxxxxxxxx>
- To: mgreim001@xxxxxxxxx, si-list@xxxxxxxxxxxxx, weirsi@xxxxxxxxxx
- Date: Wed, 5 Dec 2012 07:10:17 +0800
Hi Michael:
Yes,use the high ESR decouple capacitor was written in the application
notes, we are checking with the vendor now.
but, if it is explained by some measurement will help us to get more
information,Vendors are always smarter than me .
Besides the high ESR problem,the application notes also suggest to use
1uF 0402 capacitor below the BGA for most of the core power pins, though it
may be a traditional big-V design style, why not us 100nF or mixed number
of two caps?
It will extend the impedance curve cross the target at higher frequency,is
it because they need larger capacitance for high dynamic current but
worried about he higher Q of the anti-resonnance so they suggest to use
high ESR caps? That's my personal guess,may be wrong drection,thank you for
your helps:)
LIU Luping
·¢¼þÈË: Michael Greim <mgreim001@xxxxxxxxx>
Ö÷Ìâ: Re: [SI-LIST] Re: RE£ºHow can we get the resonance frequency and Q
between
ÊÕ¼þÈË: weirsi@xxxxxxxxxx
³ËÍ: "luping liu" <liewluping@xxxxxxxxxxxx>, si-list@xxxxxxxxxxxxx
ÈÕÆÚ: 2012Äê12ÔÂ3ÈÕ,ÖÜÒ»,ÏÂÎç9:12
LIU,
OK, I'll ask. Did you ever ask why the reference
design is this way? Is it consistent with their own
design guidelines? We are all doing alot of speculating
as to why these caps are there and it simply may have
been a board design oops, reference design or not.
Like Steve said, that is a classic, intentionally designed
in (whether meant or not) oops. You can also ask
your vendor for information about the package. Worst
thing they can say is "No", and if they ask why you have
a very good answer.
-Michael.
We will either find a way or make one - Hannibal
In the middle of every difficulty lies opportunity - Al Einstein
If you think you can do something or you think
you can't, in both cases you are probably right - H Ford
If you're not getting the results you want with the
current approach, move on and try something else. - A. Fleischmann
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