[SI-LIST] Re: DDR Vref Bypassing

Chris,

It depends on a couple of factors.  If you are going to bypass to both 
rails, it is hard to do better than X2Ys.
If your image returns are only GND as is a good idea, then bypassing the 
reference to that plane takes care f the cavity issues.

Steve

At 01:48 PM 7/18/2005 -0400, Christopher R. Johnson wrote:
>I have seen references that have Vref  bypass capacitors to both VDD and
>GND.  Other references have capacitors only to GND.   Is it really
>necessary to have "balanced" capacitors on the Vref lines?  Why?  If the
>"balanced" design is desirable, would an X2Y capacitor be a good choice,
>since it is "2 capacitors in one"?
>
>Regards,
>
>Chris Johnson
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