International Business Machines Corporation

Peter Thomas Freiburger

Todd Alan Christensen

Chad Allen Adams

Anthony Gus Aipperspach

Travis Reynold Hebig

Derick Gardner Behrends

Ryan Charles Kivimagi

Elizabeth Lair Gerhard

Daniel Mark Nelson

Jesse Daniel Smith

Peder James Paulson

John Edward Sheets, Ii

David Paul Paulsen

David Michael Friend

Douglas Michael Dewanz

Nghia Van Phan

Jayson K Wittrup

A memory interface latch including a data NAND gate and a feedback gate can be created within an integrated circuit (IC). When a feedback node is driven low, the data NAND gate can drive an inverted value of a memory array bitline input to a data output of the memory interface latch within a time of one gate delay. A feedback gate can, in a functional mode, during one phase of a clock signal, drive the feedback node high and during the other phase of the clock signal, drive the feedback node to a complement the data output. The feedback gate can be also, in an LBIST write-through mode, drive the feedback node to the value of a WRITE_DATA input. The feedback gate can be also, in a fence mode, drive the feedback node to fixed logic value.

Memory interface latch with integrated write-through and fence functions

Memory interface latch with integrated write-through function

An SRAM includes a first SRAM column having first SRAM cells and a first local evaluation logic coupled to a global bit line and a second SRAM column having second SRAM cells and a second local evaluation logic coupled to the same global bit line. The first SRAM column is selected with a first write line and the second SRAM column is selected with a second write line.

SRAM local evaluation and write logic for column selection

An SRAM includes a first SRAM column having first SRAM cells and a first local evaluation logic coupled to a global bit line and a second SRAM column having second SRAM cells and a second local evaluation logic coupled to the same global bit line. The first SRAM column is selected with a first column select line and the second SRAM column is selected with a second column select line.

SRAM local evaluation logic for column selection

A static random access memory with write-through capability includes a memory cell configured to store a bit of data. A write enable signal is configured to enable writing a write value from a write line input into the static random access memory cell and to enable reading a read value from the memory cell onto a DOT line. A local evaluation circuit is configured to place the write value from the write line onto the DOT line during a single clock cycle in which the value is being written into the memory cell. An early read suppression circuit is configured to electrically isolate the DOT line from a data out line thereby preventing a leakage current loss from the local evaluation circuit and is also configured to make the value placed on the DOT line to be read from the data out line during the single clock cycle.

Method for selectable guaranteed write-through with early read suppression

A method and a dynamic Static Random Access Memory (SRAM) circuit for implementing single bit redundancy with any bit decode, and a design structure on which the subject circuit resides are provided. The SRAM circuit includes a plurality of bitline columns and a pair of redundancy columns respectively coupled to a respective merged bit column select and redundancy steering multiplexer. Each merged bit column select and redundancy steering multiplexer receives a respective select signal input. A select signal generation circuit receives a redundancy steering signal and a respective one-hot bit select signal, generating the respective select signal input.

Implementing single bit redundancy for dynamic SRAM circuit with any bit decode

In a method of using a memory cell employing a field effect transistor (FET), the FET is heated to a first temperature sufficient to support bias temperature instability in the FET. The bit line is driven to a high voltage state. The word line is driven to a predetermined voltage state that causes bias temperature instability in the FET. The temperature, the high voltage state on the bit line and the predetermined voltage state on the word line are maintained for an amount of time sufficient to change a threshold voltage of the FET to a state where a desired data value is stored on the FET. The FET is cooled to a second temperature that is cooler than the first temperature after the amount of time has expired.

Bias temperature instability-influenced storage cell

A method and circuit for implementing substantially perfect array access time tracking with Logic Built In Self Test (LBIST) diagnostics of dynamic memory array and random logic, and a design structure on which the subject circuit resides are provided. The dynamic memory array is initialized to a state for the longest read time for each bit and the dynamic memory array is forced into a read only mode. During LBIST diagnostics with the array in the read only mode, the array outputs are combined with the data inputs to provide random switching data on the array outputs to the random logic.

Implementing enhanced array access time tracking with logic built in self test of dynamic memory and random logic

A method and circuit for implementing an enhanced dual-mode static random access memory (SRAM) performance screen ring oscillator (PSRO), and a design structure on which the subject circuit resides are provided. The dual-mode SRAM PSRO includes a plurality of SRAM base blocks connected together in a chain. Each of the plurality of SRAM base blocks includes an eight-transistor (8T) SRAM cell, a local evaluation circuit and a logic function coupled to the SRAM cell. The eight-transistor (8T) static random access memory (SRAM) cell is an unmodified 8T SRAM cell. The dual-mode SRAM PSRO includes one mode of operation, where the output frequency is determined by write-through performance of the 8T SRAM cell; and another mode of operation, where the output frequency is determined by read performance of the 8T SRAM cell.

Implementing enhanced dual mode SRAM performance screen ring oscillator

A method and circuit for implementing domino static random access memory (SRAM) local evaluation with enhanced SRAM cell stability, and a design structure on which the subject circuit resides are provided. A SRAM local evaluation circuit enabling a read and write operations of an associated SRAM cell group includes true and complement bitlines, true and complement write data propagation inputs, a precharge signal, and a precharge write signal. A respective precharge device is connected between a voltage supply VDD and the true bitline and the complement bitline. A first passgate device is connected between the complement bitline and the true write data propagation input. A second passgate device is connected between the true bitline and the complement write data propagation input. The precharge write signal disables the passgate devices during a read operation. During write operations, the precharge write signal enables the passgate devices.

Implementing local evaluation of domino read SRAM with enhanced SRAM cell stability with minimized area usage

A method and circuit for implementing an enhanced static random access memory (SRAM) read and write performance ring oscillator, and a design structure on which the subject circuit resides are provided. A plurality of SRAM base blocks is connected together in a chain. Each of the plurality of SRAM base blocks includes a SRAM cell, such as an eight-transistor (8T) static random access memory (SRAM) cell, and a local evaluation block coupled to the SRAM cell. The SRAM cell includes independent left wordline input and right wordline input. The SRAM cell includes a read wordline connected high, and a true and complement write bitline pair connected low. In the local evaluation circuit, one input of a NAND gate receiving the read bitline input is connected high. A control signal is combined with an inverted feedback signal to start and stop the ring oscillator.

Method and circuit for implementing enhanced SRAM write and read performance ring oscillator

In some aspects, an apparatus is provided. The apparatus includes a plurality of memory arrays, a latch, and a selection circuit coupled to the plurality of memory arrays and to the latch. The selection circuit may be operative to receive a bit from each of a plurality of memory arrays select one of the plurality of memory arrays, and store the bit from the selected memory array. Numerous other aspects are provided.

Methods and apparatus for testing integrated circuits

A method and enhanced Static Random Access Memory (SRAM) redundancy circuit reduce wiring and the required number of redundant elements. A bitline redundancy mechanism allows the swapping of a pair of bitlines for a redundant pair of bit columns. Two of the adjacent bitlines are swapped out at a time, one even and one odd. The swap is accomplished by steering the data around the bad columns and adding redundant columns on the end that are steered in when needed.

Method for reducing wiring and required number of redundant elements

In some aspects a method is provided for testing an integrated circuit (IC). The method includes the steps of selecting a bit from each of a plurality of memory arrays formed on an IC chip, selecting one of the plurality of memory arrays, and storing the selected bit from the selected memory array. Numerous other aspects are provided.

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Rochester, MN, United States of America

Peter Thomas Freiburger