Back to results
US 5,317,183 AGranted
Substrate noise coupling reduction for VLSI applications with mixed analog and digital circuitry
AssigneeInternational Business Machines Corporation
InventorsCharles R. Hoffman, John M. Mullen
Life of this patent
Estimating the term…
Abstract
The internal electrical noise generated by circuits of a VLSI chip is controlled by separating the logic circuit substrate contacts from the logic circuits ground contacts. A separate return path interconnects each contact to card ground. Further noise reduction is achieved by providing a void region between the noise generating devices and the "quiet" devices. A substrate contact ring is provided in the void region. The substrate contact ring is connected by a separate path to card ground.
Claims9
An improved VLSI chip comprising:
- a substrate;
- a plurality of interconnected digital devices which generate digital functions fabricated on said substrate;
- circuit means for generating analog functions fabricated on said substrate;
- at least one device contact are for coupling to at least one digital device fabricated in said substrate;
- a device ground pin (C.sub.D -GND) coupled to the chip;
- a first conductive means for forming a device ground return path interconnecting the device ground pin (C.sub.D -GND) and the at least one device contact area;
- a substrate contact region fabricated on the substrate;
- a substrate ground pin (C.sub.S -GND) coupled to the chip;
- and
- a second conductive means for forming a substrate ground return path interconnecting the substrate ground pin (C.sub.S -GND) and the substrate contact region.
7 more elements
Dependencies are inferred from the claim text.