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Browse Prior Art Database

Optimized Package for Distributing High Speed Clocks with Coax

IP.com Disclosure Number: IPCOM000106312D
Original Publication Date: 1993-Oct-01
Included in the Prior Art Database: 2005-Mar-20
Document File: 2 page(s) / 67K

Publishing Venue

IBM

Related People

Griess, KR: AUTHOR

Abstract

Disclosed is a means for fanning out a high speed, differential clock source with minimal clock-tree induced skew.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 67% of the total text.

Optimized Package for Distributing High Speed Clocks with Coax

      Disclosed is a means for fanning out a high speed, differential
clock source with minimal clock-tree induced skew.

      To minimize the skew of multiple differential clocks fanning
out from a primary distribution module, off-chip drivers are
connected to chip C4 pads that are wired radially to module pins as
shown in Fig. 1.  Two concentric rows of pins are utilized, the inner
one being for signals and the outer one being for grounds.  The
off-chip drivers and the chip C4s to which they connect, are kept as
close as possible to the circular boundary illustrated on the chip,
with differential clocks placed adjacent to one another.  The
clusters of pins at the 4 corners of the chip are used to bring in
power, ground, and the primary input clock signal.

      Fig. 2 shows a cylindrical, constant impedance connector that
mates to this module.  Coax cables come out the back end of the
connector which are electrically tuned to about 10ps by existing
techniques.  The cables maintain impedance continuity right up to the
module pin receptacles by distributing the ground and signal through
the connector at a specified spacing with a proper dielectric
material.  The connector itself can be made by "brickwalling"
individual tapered segments together, the taper providing the correct
radius for mating to the two concentric rows of module pins.

      The concentric rows of pins can be made acces...