Abstract: An integrated circuit structure comprises a static random access memory (SRAM) structure and a logic circuit. A power supply is operatively connected to the SRAM structure, and provides a first voltage to the SRAM structure. A voltage limiter is operatively connected to the power supply. The voltage limiter comprises a switching device operatively connected to the power supply. The switching device receives the first voltage and a second voltage supplied to structures external to the SRAM structure. A resistive element is operatively connected to the switching device. The switching device connects the resistive element to the power supply. The resistive element is selected to enable an output from the switching device to the logic circuit when a difference between the first voltage and the second voltage is greater than a voltage threshold value of the switching device.

Abstract: Disclosed is a memory array in which the lower of two supply voltages from two power supplies is dynamically selected for bitline pre-charge operations. In the memory array, a voltage comparator compares the first supply voltage on a first power supply rail to a second supply voltage on a second power supply rail and outputs a voltage difference signal. If the voltage difference signal has a first value indicating that the first supply voltage is equal to or less than the second supply voltage, than a control circuit ensures that the complementary bitlines connected to a memory cell are pre-charged to the first supply voltage. If the voltage difference signal has a second value indicating that the first supply voltage is greater than the second supply voltage, then the control circuit ensures that the complementary bitlines are pre-charged to the second supply voltage. Also disclosed is an associated method.

Abstract: An approach for providing fine granularity power gating of a memory array is described. In one embodiment, power supply lines are disposed in a horizontal dimension of the memory array parallel to the word lines that access cells arranged in rows and columns of the array, wherein each of the supply lines are shared by adjacent cells in the memory. Power supply lines that activate a row selected by one of the word lines are supplied a full-power voltage value and power supply lines that activate rows adjacent to the selected row are supplied a half-power voltage value, while the power supply lines of the remaining rows in the memory array are supplied a power-gated voltage value.

Abstract: The invention provides a device and method for detecting a resistive defect in a static random access memory (SRAM) device. A first aspect of the invention provides a static random access memory (SRAM) device comprising: a bitline; a wordline; a bitline precharge circuit electrically connected to the bitline and adapted to provide to the bitline a first precharge voltage for precharging the bitline during normal operation of the SRAM device and a second precharge voltage less than the first precharge voltage for testing the SRAM device for a resistive defect between the bitline and the wordline.

Abstract: Methods of setting wordline up-level voltage in as-fabricated SRAM. In one example, the method includes determining the relative speed, or strength, of 1) the combination of the pass-gate and pull-down devices and 2) the pull-up devices in the bitcells of the SRAM. These relative strengths are then used to adjust the wordline up-level voltage, if needed, to decrease the likelihood of the SRAM experiencing a stability failure. Corresponding systems are provided for determining the relative strengths of the devices of interest, for determining the amount of up-level voltage adjustment needed, and for selecting and setting the up-level voltage.

Abstract: An integrated circuit structure comprises a static random access memory (SRAM) structure and a logic circuit. A power supply is operatively connected to the SRAM structure, and provides a first voltage to the SRAM structure. A voltage limiter is operatively connected to the power supply. The voltage limiter comprises a switching device operatively connected to the power supply. The switching device receives the first voltage and a second voltage supplied to structures external to the SRAM structure. A resistive element is operatively connected to the switching device. The switching device connects the resistive element to the power supply. The resistive element is selected to enable an output from the switching device to the logic circuit when a difference between the first voltage and the second voltage is greater than a voltage threshold value of the switching device.

Abstract: An approach for providing fine granularity power gating of a memory array is described. In one embodiment, power supply lines are disposed in a horizontal dimension of the memory array parallel to the word lines that access cells arranged in rows and columns of the array, wherein each of the supply lines are shared by adjacent cells in the memory. Power supply lines that activate a row selected by one of the word lines are supplied a full-power voltage value and power supply lines that activate rows adjacent to the selected row are supplied a half-power voltage value, while the power supply lines of the remaining rows in the memory array are supplied a power-gated voltage value.

Abstract: Disclosed is a memory array in which the lower of two supply voltages from two power supplies is dynamically selected for bitline pre-charge operations. In the memory array, a voltage comparator compares the first supply voltage on a first power supply rail to a second supply voltage on a second power supply rail and outputs a voltage difference signal. If the voltage difference signal has a first value indicating that the first supply voltage is equal to or less than the second supply voltage, than a control circuit ensures that the complementary bitlines connected to a memory cell are pre-charged to the first supply voltage. If the voltage difference signal has a second value indicating that the first supply voltage is greater than the second supply voltage, then the control circuit ensures that the complementary bitlines are pre-charged to the second supply voltage. Also disclosed is an associated method.

Abstract: A dual word-line level shifter circuit and associated SRAM. A circuit is disclosed that includes a first transistor gated by a data input at the lower voltage, and a second transistor gated by a restore input at the higher voltage, wherein the first and second transistors are coupled along a series path to a source at the higher voltage; a control node along the series path; an output node coupled to the control node via a first pair of parallel transistors; and a feedback circuit having a second pair of parallel transistors and a feedback transistor, wherein the feedback transistor couples the second pair of parallel transistors to the control node and is gated by the output node.

Abstract: The invention provides a device and method for detecting a resistive defect in a static random access memory (SRAM) device. A first aspect of the invention provides a static random access memory (SRAM) device comprising: a bitline; a wordline; a bitline precharge circuit electrically connected to the bitline and adapted to provide to the bitline a first precharge voltage for precharging the bitline during normal operation of the SRAM device and a second precharge voltage less than the first precharge voltage for testing the SRAM device for a resistive defect between the bitline and the wordline.

Abstract: A static random access memory (SRAM) write assist circuit with leakage suppression and level control is described. In one embodiment, the SRAM write assist circuit increases the amount of boost provided in a write cycle, while in another embodiment, the SRAM write assist circuit limits the amount of boost provided at higher supply voltages.

Abstract: A reduced bitline precharge level has been found to increase the SRAM Beta ratio, thus improving the stability margin. The precharge level is also supplied to Sense amplifier, write driver, and source voltages for control signals. In the sense amplifier, the lower precharge voltage compensates for performance loss in the bit-cell by operating global data-line drivers with increased overdrive. In the write driver, the reduced voltage improves the Bitline discharge rate, improves the efficiency of the negative boost write assist, and decreases the reliability exposure of transistors in the write path from negative boost circuit.

Abstract: An apparatus for implementing a write assist for a memory array includes a common discharge node configured to provide a discharge path for precharged write data lines and bit lines selected during a write operation of the memory array; negative boost circuitry configured to introduce a voltage lower than a nominal logic low supply voltage onto the common discharge node following the discharge of the common discharge node, write data lines and bit lines; and a clamping device coupled to the common discharge node, the clamping device configured to limit the magnitude of negative voltage applied to common discharge node by the negative boost circuitry so as to prevent activation of non-selected bit switches.

Abstract: An SRAM delay circuit that tracks bitcell characteristics. A circuit is disclosed that includes an input node for receiving an input signal; a reference node for capturing a reference current from a plurality of reference cells; a capacitance network having a discharge that is controlled by the reference current; and an output circuit that outputs the input signal with a delay, wherein the delay is controlled by the discharge of the capacitance network.

Abstract: An integrated circuit that includes memory containing wordlines and bitcells having SRAM storage elements and being connected to the wordlines. Wordline up-level assist circuitry is provided that is designed and configured to provide a plurality of selectable voltage values that can be selected to provide the wordline up-level voltage that is provided to the bitcells during a memory read cycle and/or write cycle. In one example, the voltage value selected is selected based on characterization of the as-fabricated bitcells so as to decrease the likelihood of the bitcells experiencing a stability failure.

Abstract: A dual word-line level shifter circuit and associated SRAM. A circuit is disclosed that includes a first transistor gated by a data input at the lower voltage, and a second transistor gated by a restore input at the higher voltage, wherein the first and second transistors are coupled along a series path to a source at the higher voltage; a control node along the series path; an output node coupled to the control node via a first pair of parallel transistors; and a feedback circuit having a second pair of parallel transistors and a feedback transistor, wherein the feedback transistor couples the second pair of parallel transistors to the control node and is gated by the output node.

Abstract: A static random access memory (SRAM) write assist circuit with leakage suppression and level control is described. In one embodiment, the SRAM write assist circuit increases the amount of boost provided in a write cycle, while in another embodiment, the SRAM write assist circuit limits the amount of boost provided at higher supply voltages.

Abstract: A dual word-line level shifter circuit and associated SRAM. A circuit is disclosed that includes a first transistor gated by a data input at the lower voltage, and a second transistor gated by a restore input at the higher voltage, wherein the first and second transistors are coupled along a series path to a source at the higher voltage; a control node along the series path; an output node coupled to the control node via a first pair of parallel transistors; and a feedback circuit having a second pair of parallel transistors and a feedback transistor, wherein the feedback transistor couples the second pair of parallel transistors to the control node and is gated by the output node.

Abstract: An integrated circuit that includes memory containing wordlines and bitcells having SRAM storage elements and being connected to the wordlines. Wordline up-level assist circuitry is provided that is designed and configured to provide a plurality of selectable voltage values that can be selected to provide the wordline up-level voltage that is provided to the bitcells during a memory read cycle and/or write cycle. In one example, the voltage value selected is selected based on characterization of the as-fabricated bitcells so as to decrease the likelihood of the bitcells experiencing a stability failure.

Abstract: Methods of setting wordline up-level voltage in as-fabricated SRAM. In one example, the method includes determining the relative speed, or strength, of 1) the combination of the pass-gate and pull-down devices and 2) the pull-up devices in the bitcells of the SRAM. These relative strengths are then used to adjust the wordline up-level voltage, if needed, to decrease the likelihood of the SRAM experiencing a stability failure. Corresponding systems are provided for determining the relative strengths of the devices of interest, for determining the amount of up-level voltage adjustment needed, and for selecting and setting the up-level voltage.