[SI-LIST] Re: [SI-LIST]: Embedded capacitance on Flex..??

Steve - Yes, we have sampled both DuPont and 3M.  Dupont is very
flexible, almost like saran wrap.  The 3M material is good for hard
boards but is about as flexible as a potato chip.  Snaps like one too, I
tried it..

regards,
Larry

steve weir wrote:
> Larry, DuPont and 3M both have thin dielectric with elevated Ers that is 
> nice stuff.
> 
> Some caution is warranted though depending on the specific 
> application.  High Er material can do good things as you said.  For a given 
> skin and dielectric loss, the peak magnitude of the parallel resonant peak 
> falls approximately as the inverse square root of Er.  It tends to be even 
> better than that as higher dielectric loss pulls down the peak as 
> well.  But there are some potential rocks in that stream:
> 
> 1. Reduced board modal resonant frequencies, good for damping, potentially 
> bad if too low
> 2. Reduced board to discrete capacitor parallel resonant frequency.  Can be 
> a good or bad thing.  Introduces more variables to discrete bypass design.
> 3. Increased risk of quarter wave resonance within power delivery band 
> between discrete caps and IC die.
> 4. Much higher material cost.
> 
> Best Regards,
> 
> 
> Steve.
> At 01:24 PM 8/23/2005 -0700, Larry Smith wrote:
> 
>>Virendra - I believe that Dupont has some thin, flexible dielectric
>>that can be loaded with ceramic to bump up the dielectric constant.
>>
>>We have found that the best value comes from thin dielectric because
>>it both reduces inductance and increases capacitance resulting in
>>lower impedance.  The lower power plane impedance produces more
>>damping, which is a good for reducing power plane resonances.
>>
>>By increasing the dielectric constant alone (no dimensional changes)
>>the capacitance per square area is increased but it turns out that the
>>capacitance available to a power consumer with in a given time frame
>>(i.e. 1 nSec) is the same.  This is because the velocity of
>>electromagnetic propagation goes down with increasing dielectric.  The
>>cylindrical wavefront that goes out from a disturbance "uncovers" the
>>same amount of capacitance per time, independent of the dielectric
>>constant.
>>
>>So if you are looking for high frequency capacitance to satisfy those
>>fast edges, thin dielectric is good, high dielectric constant is
>>neutral.
>>
>>regards,
>>Larry Smith
>>Sun Microsystems
>>
>>Ray Anderson wrote:
>>
>>>Typically the way I've seen it done in the past is to use a very thin
>>>dielectric material (~2 mil thick) to achieve the higher than usual
>>>capacitance.
>>>
>>>Most hi-k materials are loaded with some sort of ceramic material which
>>>tends to make them somewhat less than flexible which could be an issue
>>>with a flex board.
>>>
>>>Note that the materials people are always developing new and innovative
>>>solutions, so what was true a couple of years ago when I looked at the
>>>issue may no longer be the case.
>>>
>>>-Ray
>>>
>>>-----Original Message-----
>>>From: si-list-bounce@xxxxxxxxxxxxx [mailto:si-list-bounce@xxxxxxxxxxxxx]
>>>On Behalf Of Virendra
>>>Sent: Tuesday, August 23, 2005 12:11 PM
>>>To: si-list@xxxxxxxxxxxxx
>>>Subject: [SI-LIST] [SI-LIST]: Embedded capacitance on Flex..??
>>>
>>>Hello All,
>>>Does anyone have experience with embedded capacitance
>>>(wih high K) on a flex circuit board? If yes, are
>>>there any issues with bending the part of the flex
>>>with the high k material..?
>>>
>>>thanks in advance,
>>>
>>>virendra
>>>
>>>__________________________________________________
>>>Do You Yahoo!?
>>>Tired of spam?  Yahoo! Mail has the best spam protection around=20
>>>http://mail.yahoo.com=20
>>>------------------------------------------------------------------
>>>To unsubscribe from si-list:
>>>si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field
>>>
>>>or to administer your membership from a web page, go to:
>>>http://www.freelists.org/webpage/si-list
>>>
>>>For help:
>>>si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field
>>>
>>>List FAQ wiki page is located at:
>>>                http://si-list.org/wiki/wiki.pl?Si-List_FAQ
>>>
>>>List technical documents are available at:
>>>                http://www.si-list.org
>>>
>>>List archives are viewable at:    =20
>>>                http://www.freelists.org/archives/si-list
>>>or at our remote archives:
>>>                http://groups.yahoo.com/group/si-list/messages
>>>Old (prior to June 6, 2001) list archives are viewable at:
>>>                http://www.qsl.net/wb6tpu
>>> =20
>>>
>>>------------------------------------------------------------------
>>>To unsubscribe from si-list:
>>>si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field
>>>
>>>or to administer your membership from a web page, go to:
>>>http://www.freelists.org/webpage/si-list
>>>
>>>For help:
>>>si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field
>>>
>>>List FAQ wiki page is located at:
>>>                http://si-list.org/wiki/wiki.pl?Si-List_FAQ
>>>
>>>List technical documents are available at:
>>>                http://www.si-list.org
>>>
>>>List archives are viewable at:
>>>                http://www.freelists.org/archives/si-list
>>>or at our remote archives:
>>>                http://groups.yahoo.com/group/si-list/messages
>>>Old (prior to June 6, 2001) list archives are viewable at:
>>>                http://www.qsl.net/wb6tpu
>>>
>>
>>------------------------------------------------------------------
>>To unsubscribe from si-list:
>>si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field
>>
>>or to administer your membership from a web page, go to:
>>http://www.freelists.org/webpage/si-list
>>
>>For help:
>>si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field
>>
>>List FAQ wiki page is located at:
>>                http://si-list.org/wiki/wiki.pl?Si-List_FAQ
>>
>>List technical documents are available at:
>>                http://www.si-list.org
>>
>>List archives are viewable at:
>>                http://www.freelists.org/archives/si-list
>>or at our remote archives:
>>                http://groups.yahoo.com/group/si-list/messages
>>Old (prior to June 6, 2001) list archives are viewable at:
>>                http://www.qsl.net/wb6tpu
>>
> 
> 
> 
> ------------------------------------------------------------------
> To unsubscribe from si-list:
> si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field
> 
> or to administer your membership from a web page, go to:
> http://www.freelists.org/webpage/si-list
> 
> For help:
> si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field
> 
> List FAQ wiki page is located at:
>                 http://si-list.org/wiki/wiki.pl?Si-List_FAQ
> 
> List technical documents are available at:
>                 http://www.si-list.org
> 
> List archives are viewable at:     
>               http://www.freelists.org/archives/si-list
> or at our remote archives:
>               http://groups.yahoo.com/group/si-list/messages
> Old (prior to June 6, 2001) list archives are viewable at:
>               http://www.qsl.net/wb6tpu
>   
> 

------------------------------------------------------------------
To unsubscribe from si-list:
si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field

or to administer your membership from a web page, go to:
http://www.freelists.org/webpage/si-list

For help:
si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field

List FAQ wiki page is located at:
                http://si-list.org/wiki/wiki.pl?Si-List_FAQ

List technical documents are available at:
                http://www.si-list.org

List archives are viewable at:     
                http://www.freelists.org/archives/si-list
or at our remote archives:
                http://groups.yahoo.com/group/si-list/messages
Old (prior to June 6, 2001) list archives are viewable at:
                http://www.qsl.net/wb6tpu

Other related posts: