Abstract: A system and method for sensing a data state stored by a memory cell that includes coupling a first digit line and a second digit line to a precharge voltage and further coupling a memory cell to the first digit line. At least one digit line other than the first and second digit lines is driven to a reference voltage level and the at least one digit line is coupled to the second digit line to establish a reference voltage in the second digit line. A voltage differential is sensed between the first digit line and the second digit line, and a data state based on the voltage differential is latched in response.

Abstract: A voltage level translator boosts the gate voltage of a transistor, and increases the gate to source voltage, to allow operation over a wider range of supply voltages. The P/N ratio of transistors in the voltage level translator is therefore increased, and control of the flipping of nodes is dependent on gate voltages as opposed to P/N ratios.

Abstract: A system and method for sensing a data state stored by a memory cell that includes coupling a first digit line and a second digit line to a precharge voltage and further coupling a memory cell to the first digit line. At least one digit line other than the first and second digit lines is driven to a reference voltage level and the at least one digit line is coupled to the second digit line to establish a reference voltage in the second digit line. A voltage differential is sensed between the first digit line and the second digit line, and a data state based on the voltage differential is latched in response.

Abstract: A memory device includes isolation trenches that are formed generally parallel to and along associated strips of active area. A conductive bit line is recessed within each isolation trench such that the uppermost surface of the bit line is recessed below the uppermost surface of the base substrate. A bit line contact strap electrically couples the bit line to the active area both along a vertical dimension of the bit line strap and along a horizontal dimension across the uppermost surface of the base substrate.

Abstract: Memory devices configured to reduce coupling noise between adjacent wordlines in a memory array. More specifically, wordline drivers are interleaved such that adjacent wordlines are driven by wordline drivers enabled by different row decoders. Each wordline driver includes a weak transistor to ground and a strong transistor to ground. By disabling the wordline driver on the wordlines directly adjacent to the active wordlines, a path is provided to drive the coupling noise from the active wordline to ground through the strong transistor.

Abstract: A voltage level shifting circuit and method that can be used for shifting the voltage level of an input signal to provide an output signal having a higher output voltage level. The voltage level shifting circuit includes pull-up transistors that are switched OFF by the voltage of a pair of switching nodes and not the voltage at the output node. The speed at which the pull-up transistors can be switched OFF is decoupled to some extent from the speed at which the voltage at the output node changes. Additionally, having the output node separated from the nodes that switch the pull-up transistors OFF further allows for dimensions of the various transistors of the voltage level shifting circuit to be scaled advantageously.

Abstract: The required refresh rate of a DRAM is reduced by biasing active digit lines to a slight positive voltage to reduce the sub threshold current leakage of access transistors in memory cells that are not being accessed. The slight positive voltage is provided by a voltage regulator circuit using one or more bipolar transistors fabricated in a well that electrically isolates the bipolar transistors from the remainder of the substrate. The voltage provided by the voltage regulator is preferably coupled to the access transistors by powering each of the n-sense amplifiers in the DRAM with the voltage from the voltage regulator.

Abstract: Apparatus and method for a current limiting bleeder device that is shared between columns of different memory arrays and limits a current load on a voltage supply to prevent failure of an otherwise repairable memory device. The memory device includes first and second memory arrays having memory cells arranged in rows and columns where each of the columns of the first and second memory arrays have a equilibration circuit to precharge the respective column. A bleeder device is coupled to a precharge voltage supply and further coupled to at least one equilibration circuit of a column in the first memory array and to at least one equilibration circuit of a column in the second memory array to limit the current drawn by the equilibration circuits from the precharge voltage supply.

Abstract: A system and method for coupling read data signals and write data signals through I/O lines of a memory array. Precharge circuits precharge alternating signal lines to high and low precharge voltages. An accelerate high circuit coupled to each of the I/O lines that has been precharged low detects an increase in the voltage of the I/O line above the precharge low voltage. The accelerate high circuit then drives the I/O line toward a high voltage, such as VCC. Similarly, an accelerate low circuit coupled to each of the I/O lines that has been precharged high detects a decrease in the voltage of the I/O line below the precharge high voltage. The accelerate low circuit then drives the I/O line to a low voltage, such as ground.

Abstract: A synchronous mirror delay (SMD)includes a model delay line that is coupled to a bi-directional delay line. In operation, an initial edge an input clock signal is applied through the model delay line to the bi-directional delay line. The SMD thereafter operates in a forward delay mode to alternately operate the bi-directional delay line in a forward mode and a backward mode to propagate the initial edge of the input clock signal through the bi-directional delay line and delay the initial edge of the input clock signal by a forward delay. In response to a subsequent edge of the input clock signal, the SMD mirrors the propagation of the input clock signal through the bi-directional delay line during the forward mode and further delay the initial edge of the input clock signal by a backward delay that is substantially equal to the forward delay.

Abstract: The required refresh rate of a DRAM is reduced by biasing active digit lines to a slight positive voltage to reduce the sub threshold current leakage of access transistors in memory cells that are not being accessed. The slight positive voltage is provided by a voltage regulator circuit using one or more bipolar transistors fabricated in a well that electrically isolates the bipolar transistors from the remainder of the substrate. The voltage provided by the voltage regulator is preferably coupled to the access transistors by powering each of the n-sense amplifiers in the DRAM with the voltage from the voltage regulator.

Abstract: Selective coupling devices directed by coupling controllers prevent cell plate and/or substrate disturbances from causing memory cell read and refresh errors in open digit line array memory devices. Using selective decoupling devices, when memory cells in an active row store an appreciably unbalanced number of either zeroes or ones, reading the cells generates a voltage transient in the cell plate and/or substrate that can be coupled to a reference digit line because the cell plates and/or substrates of the active sub-array are normally coupled to the cell plates and/or substrates of the reference arrays. By decoupling the cell plate and/or substrate of the active sub-array from the cell plates and/or substrates of the reference arrays, any coupling of the voltage transients to reference digit lines is reduced.

Abstract: The disclosed system and method introduce voltage disturbances into a reference sub-array to offset voltage disturbances occurring in an active sub-array. The disclosed system and method connect extra, unused rows of memory cells to currently unused digitlines in the reference sub-array to cause surges that create voltage disturbances like those occurring in the active sub-array as a consequence of rows of memory cells in the active sub-array being connected to the active digitlines. As a result, when the sense amplifiers compare the voltages received on the active digitlines and the reference digitlines, the effects of the voltage disturbances on the active and reference digitlines lines offset each other.

Abstract: A synchronous mirror delay includes a ring oscillator that generates a plurality of tap clock signals with one tap clock signal being designated an oscillator clock signal. In response to an input clock signal, a model delay line generates a model delayed clock signal having a model delay relative to the input clock signal. A coarse delay circuit generates a coarse delay count responsive to the oscillator, input, and model delayed clock signals, and activates a coarse delay enable signal responsive to the delay count being equal to a reference count value. A fine delay circuit latches the tap clock signals and develops a fine delay from the latched signals, and activates a fine delay enable signal having the fine delay in response to the coarse delay enable signal. An output circuit generates a delayed clock signal responsive to the coarse and fine delay enable signals going active.

Abstract: A memory device such as a 6F2 memory device includes isolation trenches that are formed generally parallel to and along associated strips of active area. A conductive bit line is recessed within each isolation trench such that the uppermost surface of the bit line is recessed below the uppermost surface of the base substrate. A bit line contact strap electrically couples the bit line to the active area both along a vertical dimension of the bit line strap and along a horizontal dimension across the uppermost surface of the base substrate.

Abstract: A delay-locked loop includes a ring oscillator that generates a plurality of tap clock signals, with one tap clock signal being designated an oscillator clock signal. Each tap clock signal has a respective delay relative to the oscillator clock signal. The oscillator clock signal clocks a coarse delay counter to develop a coarse delay count that determines a coarse delay of a delayed clock signal. A fine delay of the delayed clock signal is determined by selecting one of the tap clock signals of the ring oscillator. The phase between an in put clock signal and the delayed clock signal is determined and the coarse and fine delays adjusted in response to this phase to synchronize the delayed and input clock signals. The delay-locked loop may also monitor rising and falling edges of the input clock signal and develop corresponding rising-edge and falling-edge fine delays to synchronize rising and failing edges of the input clock signal.

Abstract: A system and method for coupling read data signals and write data signals through I/O lines of a memory array. Precharge circuits precharge alternating signal lines to high and low precharge voltages. An accelerate high circuit coupled to each of the I/O lines that has been precharged low detects an increase in the voltage of the I/O line above the precharge low voltage. The accelerate high circuit then drives the I/O line toward a high voltage, such as VCC. Similarly, an accelerate low circuit coupled to each of the I/O lines that has been precharged high detects a decrease in the voltage of the I/O line below the precharge high voltage. The accelerate low circuit then drives the I/O line to a low voltage, such as ground.

Abstract: Selective coupling devices directed by coupling controllers prevent cell plate and/or substrate disturbances from causing memory cell read and refresh errors in open digit line array memory devices. Using selective decoupling devices, when memory cells in an active row store an appreciably unbalanced number of either zeroes or ones, reading the cells generates a voltage transient in the cell plate and/or substrate that can be coupled to a reference digit line because the cell plates and/or substrates of the active sub-array are normally coupled to the cell plates and/or substrates of the reference arrays. By decoupling the cell plate and/or substrate of the active sub-array from the cell plates and/or substrates of the reference arrays, any coupling of the voltage transients to reference digit lines is reduced.

Abstract: A delay-locked loop includes a ring oscillator that generates a plurality of tap clock signals, with one tap clock signal being designated an oscillator clock signal. Each tap clock signal has a respective delay relative to the oscillator clock signal. The oscillator clock signal clocks a coarse delay counter to develop a coarse delay count that determines a coarse delay of a delayed clock signal. A fine delay of the delayed clock signal is determined by selecting one of the tap clock signals of the ring oscillator. The phase between an input clock signal and the delayed clock signal is determined and the coarse and fine delays adjusted in response to this phase to synchronize the delayed and input clock signals. The delay-locked loop may also monitor rising and falling edges of the input clock signal and develop corresponding rising-edge and falling-edge fine delays to synchronize rising and falling edges of the input clock signal.

Abstract: A synchronous mirror delay includes a ring oscillator that generates a plurality of tap clock signals with one tap clock signal being designated an oscillator clock signal. In response to an input clock signal, a model delay line generates a model delayed clock signal having a model delay relative to the input clock signal. A coarse delay circuit generates a coarse delay count responsive to the oscillator, input, and model delayed clock signals, and activates a coarse delay enable signal responsive to the delay count being equal to a reference count value. A fine delay circuit latches the tap clock signals and develops a fine delay from the latched signals, and activates a fine delay enable signal having the fine delay in response to the coarse delay enable signal. An output circuit generates a delayed clock signal responsive to the coarse and fine delay enable signals going active.