International Business Machines Corporation

Gordon B Sapp

Rolf Sautter

Harry S Barowski

Sheldon Bernard Levenstein

Pradip Patel

Daniel Rodko

Alexander Fritsch

Amira Rozenfeld

Ananth Nag Raja Darla

Praveen Patavardhan

The present invention provides a system and method of testing CAMs and RAMs. In an exemplary embodiment, the system includes a multiple input signature register (MISR) logically coupled to digital outputs of a CAM, to digital inputs of a RAM, and to digital outputs of an ABIST controller circuit, where the MISR includes a plurality of L1 latch circuits logically coupled to a plurality of L2 latch circuits, a plurality of multiplexer circuits logically coupled to the plurality of L1 latch circuits, a plurality of exclusive or circuits (inner XOR circuits) logically coupled to the plurality of MUX circuits and to the plurality of L2 latch circuits, and at least two XOR circuits (outer XOR circuits), each of the outer XOR circuits logically coupled to one of the inner XOR circuits, to at least one of the MUX circuits, and to at least one of the L2 latch circuits.

Testing content addressable memory and random access memory

A content addressable memory (CAM) cell system is provided. The CAM cell system includes a first memory cell, a first logic circuitry and a first compare circuitry. The first logic circuit includes a first n-FET, a first p-FET, and a first input terminal. A gate of the first n-FET and a gate of the first p-FET are galvanically coupled to the first input terminal. The first compare circuitry is communicatively coupled to the first memory cell via a first coupling, and to the first input terminal via a second coupling. The first compare circuitry is configured to receive first data stored in the first memory cell via the first coupling, receive first match data, transmit a first binary logical value to the first input terminal via the second coupling in response to the first data not matching the first match data, and transmit a second binary logical value to the first input terminal via the second coupling in response to the first data matching the first match data.

Content addressable memory cell and array

Disclosed aspects include a content addressable memory device comprising at least two memory banks connectable to a global search line. Each memory bank comprises at least two content addressable memory cells. Each content addressable memory cell can store one bit. Each content addressable memory cell is coupled to a respective local search line. Aspects include a bank connection circuitry configured for coupling the global search line to the local search lines in dependence of a bank prediction signal line. The bank connection circuitry of the content addressable memory device may comprise bank hold circuitry for storing a search value transmitted by the global search line.

Content addressable memory device

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Austin, TX, United States of America

Gordon B Sapp