07/30/97 01:30 AM
Please respond to owner-si-list@silab.Eng.Sun.COM @ internet
To: si-list@silab.Eng.Sun.COM @ internet
cc: email@example.com @ internet
Subject: [SI-LIST] : Buried Capacitors
I am trying to gain a better understanding on the concept of the buried
capacitors, made of two (2) internal planes on a printed circuit board.
We do not have a general agreement within the design community on the use
of this technique, so I just wanted to bounce it off of this reflector.
Multi-layer PCB's have power and ground planes as a norm. This technique
stacks some of these planes very close together (2 mil thin dielectrics)
to act as a giant capacitor.
The design uses thru-hole vias only.
1) reducing noise
2) using this as an alternative to filter-caps
3) using this in conjunction with filter-caps.
4) At what frequencies is this practice appropriate.
5) anything else you can add.