Re: [SI-LIST] : Re: Backplane Board insertion problem

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From: Bill Owsley (owsley@cisco.com)
Date: Wed Dec 06 2000 - 09:31:18 PST


I would guess first at the power supply being marginally controlled and
it's ringing, not the backplane. But hey, stranger things have happened.

At 11:30 AM 12/06/2000 -0500, Dennis Schmitz wrote:
>We removed all components from the power section of the board, except for
>the fuses. We suspect that the capacitance of the power planes on the board
>itself pings the backplane causing the resonant response.
>
>----- Original Message -----
>From: "Mendelsohn, Joseph P (Joseph)" <jmendelsohn@lucent.com>
>To: "si-list" <si-list@silab.eng.sun.com>
>Cc: "'Dennis Schmitz'" <den@positron.net>
>Sent: Wednesday, December 06, 2000 11:14 AM
>Subject: Backplane Board insertion problem
>
>
> > I would tend to agree with Mark. You probably do not have enough
> > capacitance in the backplane, or you do not have an inrush(soft-start)
> > circuit. There are many ways to avoid this problem. Check out the
> > following brief in EDN
> > http://www.ednmag.com/ednmag/reg/1997/121897/26di_07.htm
> > <http://www.ednmag.com/ednmag/reg/1997/121897/26di_07.htm> . This type of
> > circuit or, a simple MOSFET with a set RC time constant can help.
> >
> > Joseph
> >
> > -----Original Message-----
> > From: Mark Gill [mailto:gillmf@nortelnetworks.com]
> > Sent: Wednesday, December 06, 2000 9:22 AM
> > To: 'Dennis Schmitz'; si-list
> > Subject: RE: [SI-LIST] : Capacitor dielectric type
> >
> >
> > Dennis -
> >
> > Your board insertion problem sounds more like an in-rush current problem
> > than power plane resonance. Do you have further details which would
>confirm
> > resonance over inrush?
> >
> > Mark
> >
> > -----Original Message-----
> > From: Dennis Schmitz [mailto:den@positron.net]
> > Sent: Tuesday, December 05, 2000 5:38 PM
> > To: si-list
> > Subject: Re: [SI-LIST] : Capacitor dielectric type
> >
> >
> > Can some kind person please point me to some references on power-plane
> > resonance? I am researching for a new backplane design of an existing
>system
> > where we are having some problems with board insertion causing
>disturbances
> > on the power distribution planes.
> >
> > Thanks in advance.
> >
> >
>
>
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----------------------------
Bill Owsley, owsley@cisco.com
919) 392-8341

Compliance Engineer
Cisco Systems
7025 Kit Creek Road
POB 14987
RTP. NC. 27709

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