Browse Prior Art Database

Off Chip Driver Noise Reduction of Pin Grid Arrays

IP.com Disclosure Number: IPCOM000119189D
Original Publication Date: 1995-Dec-01
Included in the Prior Art Database: 2005-Apr-01
Document File: 2 page(s) / 39K

Publishing Venue

IBM

Related People

Frech, R: AUTHOR [+3]

Abstract

In Fig. 1, the improved structure is shown. To reduce the coupling of the border signal pins Se, additional card/board vias Sc are introduced. They act as shield between the border signal vias and, therefore, the OCD noise of these signal pins is reduced to values which are close to the noise values of the inner signal pins.

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Off Chip Driver Noise Reduction of Pin Grid Arrays

      In Fig. 1, the improved structure is shown.  To reduce the
coupling of the border signal pins Se, additional card/board vias Sc
are introduced.  They act as shield between the border signal vias
and, therefore, the OCD noise of these signal pins is reduced to
values which are close to the noise values of the inner signal pins.

      The major part of the OCD noise of pin/vias is caused by the
via coupling in the card or board.

      The vias Sc are connected to all GND planes in the card or
board.  They can be implemented into the design either by the
component rule which is generated for the physical design, or by new
additional vias during the card and board design.

      This principle can be applied for all pin grid array modules
(single and multichip), all solder ball grid arrays and all pin
connector types.

      Furthermore, not only the OCD noise is reduced by using the
additional via structures, but also the electromagnetic radiation of
the border section.  In addition, the Sc vias give GND reference pads
for card and board repair wires.

The improved pin grid structure has the following advantages:
  o  OCD noise reduction for border signal pins/vias by a factor of
      2.5.
  o  Reduction of EMC radiation.
  o  Gives GND reference on card and board for repair wires.
  o  Simple implementation into (even already existing) physical
      design.
  o  Application...