International Business Machines Corporation

Peter Francis Croce

Steven Michael Eustis

Robert L Barry

Yabin Wang

Ronald A Piro

A method and structure for a read only memory (ROM) cell array has the first drain of a first transistor connected to a true bitline and a second drain of a second transistor connected to a complement bitline. The first transistor also includes a first source, and the second transistor includes a second source. The connection of the first source or the second source to ground programs the ROM cell. With the invention, only the first source or the second source is connected to the ground and the other is insulated from electrical connections. Further, the connection of the source to ground comprises an electrical connection formed during manufacturing of the first transistor and the second transistor.

Complementary two transistor ROM cell

A method of designing an integrated circuit chip includes preparing a first macro to have a first power consumption rate, preparing a second macro to have a second power consumption rate different than the first power consumption rate, designing the circuit, measuring performance characteristics of the circuit, and substituting the second macro for the first macro to improve the performance characteristics. The first macro and the second macro have the same function, devices, surface area size, external wiring pattern, and timing characteristics.

Substituting high performance and low power macros in integrated circuit chips

A memory circuitry is designed to efficiently obtain a predictable array output when an invalid address is requested. The memory circuit comprises an invalid word line path in addition to the standard valid word line path. In order to provide correct output, a dummy word line output of a first decode logic is delayed and the delayed dummy word line output is ANDed with a word line output to update the data out latch. Further, the invalid word line output of a second decode logic is also delayed, and the delayed invalid word line output is ORed with the delayed dummy word line output to reset the control logic. ORing the delayed signals allows the predictable output to be provided at a same clock time, irrespective of whether a valid address or an invalid address is decoded.

Memory circuitry with auxiliary word line to obtain predictable array output when an invalid address is requested

A method and structure for a pair of read only memory (ROM) cells having a first latch and a second latch connected to the first latch. The first latch and the second latch behave as master and slave latches to one another. The first latch and the second latch include a write bitline connection that is permanently connected to a fixed voltage source to permanently program the first latch and the second latch to permanent ROM values.

Growing community of inventors

Essex Junction, VT, United States of America

Peter Francis Croce