RE: [SI-LIST] : RE: Another decoupling question

Mellitz, Richard (richard.mellitz@intel.com)
Thu, 16 Sep 1999 08:26:34 -0700

How about a barium titinate layer (Dk~100) between power and ground in a
multilayer ceramic package? It should get you about 20 nF or so?
Is anyone doing this?

... Rich Mellitz
Intel

-----Original Message-----
From: Greim, Michael [mailto:mgreim@mc.com]
Sent: Thursday, September 16, 1999 8:50 AM
To: 'si-list@silab.eng.sun.com, "Volk, Andrew M"';
'si-list@silab.eng.sun.com'
Subject: [SI-LIST] : RE: Another decoupling question

I can appreciate the value of that, however, I would think
that
most manufacturing folks would run kicking and screaming
from a multi-stage assembly approach. What happens when
the caps fail as a short. You end up having to pull
up/reball
and perhaps scrap a potentially expensive BGA to save the
.01 cent capacitor.

From a manufacturability perspective, I would advocate
getting
as close as possible to the outer edge of the chip and
decoupling
on the opposite side of the board. Chips on top of chips is
a
bad idea. IMHO.

Michael C. Greim
Consulting Engineer
Mercury Computer Systems, Inc email: mgreim@mc.com
199 Riverneck Road V:
978-256-0052/x1607
Chelmsford, MA 01824-2820 F:
978-256-4778

> -----Original Message-----
> From: Volk, Andrew M [SMTP:andrew.m.volk@intel.com]
> Sent: Wednesday, September 15, 1999 5:04 PM
> To: 'si-list@silab.eng.sun.com'
> Subject: RE: Another decoupling question
>
> SI Listeners -
>
> Another question on decoupling. I have recently heard
about capacitors
> that are supposedly thin enough to fit under a standard
MBGA package
> (Novacap for one). This would give excellent decoupling
as it is close to
> the package power balls, but still mounts on the top of
the board avoiding
> backside components.
>
> Has anyone had any experience with this type of device and
this kind of
> manufacturing step (cap under BGA package)?
>
> Andrew Volk
> Intel Corp.

**** To unsubscribe from si-list: send e-mail to
majordomo@silab.eng.sun.com. In the BODY of message put: UNSUBSCRIBE
si-list, for more help, put HELP. si-list archives are accessible at
http://www.qsl.net/wb6tpu/si-list ****

**** To unsubscribe from si-list: send e-mail to majordomo@silab.eng.sun.com. In the BODY of message put: UNSUBSCRIBE si-list, for more help, put HELP. si-list archives are accessible at http://www.qsl.net/wb6tpu/si-list ****