Abstract: A method of implementing a self-referencing read operation for a PCRAM array includes applying a stimulus to a bit line associated with a selected phase change element (PCE) to be read; comparing a first voltage on a node of the bit line with a second voltage on a delay node, wherein the second voltage represents a delayed voltage with respect to the first voltage due to a resistance/capacitance time constant associated therewith; and determining whether, during the read operation, the first voltage drops below the value of the second voltage; wherein in the event the first voltage drops below the value of the second voltage during the read operation, the PCE is determined to be programmed to an amorphous state and in the event the first voltage does not drop below the value of the second voltage, the PCE is determined to be programmed to a crystalline state.

Abstract: A method of implementing a self-referencing read operation for a PCRAM array includes applying a stimulus to a bit line associated with a selected phase change element (PCE) to be read; comparing a first voltage on a node of the bit line with a second voltage on a delay node, wherein the second voltage represents a delayed voltage with respect to the first voltage due to a resistance/capacitance time constant associated therewith; and determining whether, during the read operation, the first voltage drops below the value of the second voltage; wherein in the event the first voltage drops below the value of the second voltage during the read operation, the PCE is determined to be programmed to an amorphous state and in the event the first voltage does not drop below the value of the second voltage, the PCE is determined to be programmed to a crystalline state.

Abstract: Disclosed is a design structure of an improved large scale memory system and, more particularly, an improved memory system that incorporates an array of memory cells that are subjected to minimal location dependent power variations and that, optionally, allows for bi-directional random access of millions of bits. Specifically, the system architecture provides a consistent amount of bit line resistance in the write and read paths to each memory cell in the array, independent of position, in order to minimize variations in power delivery to the cells and, thereby, allow for optimal cell distributions. The system architecture further allows current to pass in either direction through the cells in order to minimize element electro-migration and, thereby, extend memory cell life.