Browse Prior Art Database

Low Inductance Edge Connection Technique

IP.com Disclosure Number: IPCOM000050933D
Original Publication Date: 1982-Dec-01
Included in the Prior Art Database: 2005-Feb-10
Document File: 3 page(s) / 70K

Publishing Venue

IBM

Related People

Van der Hoeven, BJ: AUTHOR [+2]

Abstract

Use of niobium connectors for the ground plane and also for the X and Y connectors permits solder to be deposited directly on the connectors and thus permits the distances between edges of the ground plane and signal fillets to be minimized, minimizing inductance and minimizing the need to assign fillets as ground connectors rather than signal connectors.

This text was extracted from a PDF file.
At least one non-text object (such as an image or picture) has been suppressed.
This is the abbreviated version, containing approximately 54% of the total text.

Page 1 of 3

Low Inductance Edge Connection Technique

Use of niobium connectors for the ground plane and also for the X and Y connectors permits solder to be deposited directly on the connectors and thus permits the distances between edges of the ground plane and signal fillets to be minimized, minimizing inductance and minimizing the need to assign fillets as ground connectors rather than signal connectors.

The right-angle electrical connectors between a carrier and a foot consist of a linear array of fillets. The linear density of signal fillets becomes a bottleneck in the number of signal I/Os available on a card. This fillet structure reduces the inductance (L) by a factor of approximately 3 and results in 20-50 per cent (depending on signal:ground fillet ratio of 1.5:1 or 3:1) more signal fillets than the case of signal:ground=1:1.

The total distance between the edges of ground planes on the carrier and on the foot is (for a signal fillet) the sum of the following terms:
Lambda(F)= Distance between edge of ground plane and edge of foot near carrier.

Lambda(G)= Gap between foot and carrier when they are bonded.

This fillet structure with Lambda approximately 25 Micron(m), Lambda =5 - 13 Micron(m) and Lambda approximately 30 - 38 Micron(m) has an estimated L approximately 30 pH. (Since the inductance L depends not only on Lambda but also on the separation between the signal and ground fillets, the reduction in L does not scale directly with Lambda.)

Fig. 1 shows the signal and ground fillets on a foot with all niobium wiring (ground plane, X, + Y s M1, M2, M4, respectively); the wiring is shown expanded on the carrier for clarity. With M2 and M4 made of niobium, the...