[SI-LIST] Re: anti-resonance point when use Embedded Capacitance Material
- From: Ken Wyatt <ken@xxxxxxxxxxxxxxxx>
- To: Charles.Grasso@xxxxxxxxxxxx
- Date: Thu, 9 May 2013 14:53:34 -0700
Thanks Chas,
I remember those days...things have progressed greatly.
Do you, or the group, know of affordable simulation S/W (Ansoft, maybe?) that
would simulate plane resonances? My limited budget won't support multi-G$ S/W,
unfortunately. That would be pretty cool to be able to simulate that. I saw a
recent demo of HyperLynx that was impressive.
I know Istvan has several Excel calculators that will model PDN impedances.
You coming to the Denver symposium this year?
Cheers, Ken
___________________
Kenneth Wyatt
Wyatt Technical Services LLC
Woodland Park, CO
ken@xxxxxxxxxxxxxxxx
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On May 9, 2013, at 2:22 PM, Grasso, Charles wrote:
> Hello Ken,
>
> When faced with large areas of pwb that have little or no components, it used
> common practice for EMI guys to add lossy caps (the lossier the better)
> to the planes in a regular pattern to minimize the effects of plane
> resonance. With modern simulation tools, the resonant modes of the planes
> can be simulated and caps added (in just the right spot!) to reduce the
> effect.
>
> Chas
>
> -----Original Message-----
> From: si-list-bounce@xxxxxxxxxxxxx [mailto:si-list-bounce@xxxxxxxxxxxxx] On
> Behalf Of Istvan Novak
> Sent: Thursday, May 09, 2013 7:23 AM
> To: Ken Wyatt
> Cc: bruce@xxxxxxxxxx; si-list@xxxxxxxxxxxxx
> Subject: [SI-LIST] Re: anti-resonance point when use Embedded Capacitance
> Material
>
> Ken,
> Bypass capacitors with more lossy dielectrics do help somewhat, but the
> dielectric loss shows up strongly in the ESR only at frequencies much lower
> than the series resonance frequency, where we usually dont need the higher
> ESR. Very lossy (and sloppy) dielectrics, such as Z5U and Y5V are good for
> cheap consumer electronics, but for professional circuits there are many
> drawbacks and it is not the best thing to use them. Ceramic capacitors with
> user-defined ESR are available from two of the major capacitor vendors, so
> they can be used when we need the highest performance and can afford the
> higher cost for these parts.
>
> Regards,
>
> Istvan Novak
> Oracle
>
>
>
>
> On 5/9/2013 9:00 AM, Ken Wyatt wrote:
>> Hi Group & Bruce,
>>
>> I'm kind of a "newby" when it comes to SI, but am reading Lee Richey's
>> books on the subject.
>>
>> One thing he recommends for PDN designs is the use of bypass
>> capacitors with a more lossy dielectric (higher ESR), such as X5R, Z5U
>> or Y5V, to dampen the anti-resonance. Would this be a reasonable thing
>> to try?
>>
>> Ken
>> ___________________
>> Kenneth Wyatt
>> Wyatt Technical Services LLC
>> Woodland Park, CO
>> ken@xxxxxxxxxxxxxxxx <mailto:ken@xxxxxxxxxxxxxxxx> Web
>> <http://www.emc-seminars.com> Newsletter
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>>
>> On May 9, 2013, at 5:16 AM, Istvan Novak wrote:
>>
>>> Hi Bruce,
>>>
>>> The anti-resonance between the static capacitance of planes and
>>> inductance of bypass capacitors will always be present unless you
>>> either match the plane impedance with the ESRs of capacitors or
>>> overwhelm the antiresonance with MANY low-inductance bypass
>>> capacitors. The antiresonance is present with any laminate material, thin
>>> or thick.
>>> When you use thin laminates (Embedded Capacitance Material), the
>>> resonance magnitude and frequency both get lower with respect to a
>>> thicker laminate. First you have to determine whether the resonance
>>> causes a problem for power, signal integrity and EMI. If you dont
>>> excite the resonance, you dont need to care.
>>>
>>> Regards,
>>>
>>> Istvan Novak
>>> Oracle
>>>
>>>
>>>
>>>
>>> On 5/9/2013 2:26 AM, Bruce wrote:
>>>> Hi Expert
>>>>
>>>>
>>>> We use Embedded Capacitance Material for better PDN and less
>>>> capacitor component. According to PDN Simulation. We notice that is
>>>> an anti-resonance point between capacitor and Plane.
>>>>
>>>>
>>>>
>>>> We can find that when use Embedded Capacitance Material. There are
>>>> much better in most frequency but near anti-resonance point.
>>>>
>>>>
>>>>
>>>> In this case. We have to solution.
>>>>
>>>> 1. Try to reduce the anti-resonance point. We need many high
>>>> frequency
>>>> capacitor component. That is not good because we want to reduce the
>>>> number of capacitor component. Our purpose is reduce 70% number of
>>>> capacitor component.
>>>>
>>>> 2. Keep this anti-resonance point. That maybe have a risk if
>>>> there is
>>>> some noise by chance in this frequency
>>>>
>>>>
>>>>
>>>> How about your suggestion? Please let me know if my question is not
>>>> clear enough.
>>>>
>>>> Thanks
>>>>
>>>>
>>>>
>>>> Best Regards,
>>>>
>>>> Bruce Wu
>>>>
>>>>
>>>>
>>>>
>>>
>>>
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>>
>
>
>
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