International Business Machines Corporation

Guy Rabbat

Haluk O Askin

Joseph R Cavaliere

John Balyoz

Bryant K Ho

Achilles A Sarris

Doyle E Beaty, Jr

A very large scale multicell integrated circuit is provided with significantly improved circuit density. Both active and passive circuit elements are formed in a semiconductor substrate using ordinary diffusion techniques. Connectors, preferably made of polysilicon material, are then formed on the surface of the substrate. The connectors have bonding pad areas located along predetermined lines where metal connectors of later-formed metallization layers can be located. Some of the connectors have bonding pad areas connected to circuit elements while others are left unconnected. The subsequently formed metallization layers can then be used to connect together various ones of the circuit elements and multiple ones of the cells together in any desired circuit configuration using the polysilicon connectors.

VLSI integrated circuit having parallel bonding areas

A communication circuit for transmitting multi-bit digital signals from one integrated circuit to another upon a single conductor utilizing a multi-level analog signal. The transmitting circuitry includes first through third drivers, only one of which is activated at any one time. The collector of an output transistor of a first of the drivers is coupled directly to the single bus conductor, the collector of an output transistor of the second driver is coupled to the bus through a single transistor, and the collector of an output transistor of the third driver is coupled to the bus through two series-connected diodes. The receiving circuitry is composed of three receivers, each including an input and output transistor pair coupled in a Darlington configuration. The base of the input transistor of the first receiver is coupled to the bus through a single diode connected in a first direction, the second receiver coupled to the input bus through a diode in a direction opposite the first direction, and the third receiver is coupled to the input bus via two series-connected diodes, this arrangement of diodes providing three different threshold voltage levels. The outputs of the three receivers are combined to yield an output digital signal which corresponds to the input digital signal.

Multi-level communication circuitry for communicating digital signals

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Wappingers Falls, NY, United States of America

Guy Rabbat