Robert A Petty

US Patent:

54244927, Jun 13, 1995

Filed:

Jan 6, 1994

Appl. No.:

8/178078

Inventors:

Robert B. Petty - Austin TX
Michael D. Ohlinger - Austin TX
Deepak N. Swamy - Austin TX
Joseph Mallory - Cedar Park TX

Assignee:

Dell USA, L.P. - Austin TX

International Classification:

H05K 100

US Classification:

174250

Abstract:

An optimal routing methodology for routing high I/O density packages which minimizes the number of PCB layers required. One feature of this routing methodology comprises treating respective I/O that are routed at the top layer of the package as surface mount technology (SMT) pads without dropping vias within the BGA grid, as is commonplace in the industry. This facilitates the use of fewer escapes and allows for more efficient use of the available space. Signal lines on the top layer of the package which must be routed to other layers of the PCB are connected to vias outside of the area of local high signal density on the printed circuit board. The placement of vias outside the area of local high density, i. e. , in a depopulated area, reduces the number of layers necessary in the PCB to properly route the signals. This placement also facilitates the use of filtering capacitors to meet EMI requirements.

US Patent:

59557044, Sep 21, 1999

Filed:

Nov 21, 1996

Appl. No.:

8/754763

Inventors:

Leroy Jones - Austin TX
Robert Petty - Austin TX

Assignee:

Dell U.S.A., L.P. - Round Rock TX

International Classification:

H05K 900
H05K 111

US Classification:

174262

Abstract:

A computer system includes a multi-layer circuit board having first and second routing layers. A component including pads is mounted on the first layer. Crosstalk protection is provided by a plurality of ground vias and signal vias adjacent to the component and extending between the first and second layers. A first circuit trace extends from a first pad along the first layer and between two adjacent ones of the ground vias. A second circuit trace extends from a second pad along the first layer to a signal via at the first layer and from the signal via along the second layer between the two adjacent ground vias.