Abstract: A data read circuit and method for use in a semiconductor memory device that has a memory cell array are provided. The circuit includes a selector for selecting a unit cell within the memory cell array in response to an address signal; a clamping unit for supplying a clamp voltage having a level for a read operation to a bit line of the selected unit cell in response to a clamp control signal; a precharge unit for precharging a sensing node to a voltage having a power source level in response to a control signal of a first state in a precharge mode, and compensating through the sensing node for a reduced quantity of current at the bit line in response to a control signal of a second state in a data sensing mode; and a sense amplifier unit for comparing a level of the sensing node with a reference level, and for sensing data stored in the selected unit cell.

Abstract: A semiconductor memory device, which has an array of memory cells connected with a plurality of bit line pairs and a plurality of word lines, to perform a read or write operation of data, having low power consumption is provided. The device includes a first power supply for supplying a first power source voltage. Also, a second power supply supplies a second power source voltage having a lower voltage level than the first power source voltage. Further, the device includes a standard ground. An elevated ground circuit provides an elevated ground voltage having a higher voltage level than that of the standard ground. A first power circuit is connected with the first power supply and the standard ground, and operates in response to the first power source voltage. A second power circuit is connected with the second power supply and the elevated ground circuit, and operates in response to the second power source voltage. Thereby, power and chip size can be reduced.

Abstract: A method for programming a phase-change memory array and circuit of a phase-change memory device, each having a plurality of phase-change memory cells, may enable all the phase-change memory cells therein to be changed or set at a set resistance state, and may reduce the time needed to change the phase-change memory array to the set resistance state. In the method, a set current pulse having first through nth stages may be applied to the cells of the array to change the cells to the set resistance state. A minimum current level of the set current pulse applied to the phase-change memory cells in any stage may be higher than a reference current level for the cells of the array. A given current level of the set current pulse may be sequentially reduced from stage to stage.

Abstract: A write driver circuit including a plurality of programmable fuses for a phase change memory device in which a write operation is correctly performed even in the case where a current output shift in a write current generation circuit; or in the case where a phase change memory cell having a phase change property shift due to an external factor or due a process change. The write driver circuit includes a write current control unit for outputting a first or second level of voltage selected, by selecting one of a first or second programmable current path, based on whether a first or second selection pulse signal is applied; and a current driving unit for generating a write current controlled by the output voltage of the write current control unit.

Abstract: A phase-change cell memory device includes a plurality of phase-change memory cells, an address circuit, a write driver, and a write driver control circuit. The phase-change memory cells each include a volume of material that is programmable between amorphous and crystalline states. The address circuit selects at least one of the memory cells, and the write driver generates a reset pulse current to program a memory cell selected by the address circuit into the amorphous state, and a set pulse current to program the memory cell selected by the address circuit into the crystalline state. The write driver control circuit varies at least one of a pulse width and a pulse count of at least one of the reset and set pulse currents according to a load between the write driver and the memory cell selected by the address circuit.

Abstract: A write driver circuit including a plurality of programmable fuses for a phase change memory device in which a write operation is correctly performed even in the case where a current output shift in a write current generation circuit; or in the case where a phase change memory cell has a phase change property shift due to an external factor or due a process change. The write driver circuit includes; a write current control unit for outputting a first or second level of voltage selected, by selecting one of a first or second programmable current path, based on whether a first or second selection pulse signal is applied; and a current driving unit for generating a write current controlled by the output voltage of the write current control unit.

Abstract: In a mode entrance control circuit and a mode entering method to stably enter a semiconductor memory device into a predetermined operating mode only when insensitive to a change of a process, temperature, or voltage, etc., and simultaneously satisfying a constant entrance condition, the mode entrance control circuit includes an operation control part for generating an operation enable signal when a first voltage applied through a first pad is over a first determination voltage, a voltage division part for dividing a second voltage applied through a second pad to generate a trimming reference voltage, and a mode entrance signal generating part operated in response to the operation enable signal, for comparing a level of an applied fixed reference voltage with a level of the trimming reference voltage, and for generating a mode entrance enable signal to allow the semiconductor memory device to enter into a predetermined mode.

Abstract: A firing method of a phase change memory device and a phase change memory capable of effectively performing a firing operation are described. The phase change memory device includes a plurality of memory cell array blocks, a counter clock generation unit, a decoding unit, and a driving unit. Each memory cell array block has phase change memory cells. The counter clock generation unit outputs first through third counter clock signals in response to an external clock signal and a firing mode signal, wherein the first through third counter clock signals have different cycles. The decoding unit, in response to the first through third counter clock signals, outputs a block address which selects one of the plurality of memory cell array blocks, word line addresses which enable word lines of the selected memory cell array block, and a redundant word line address which enables a redundant word line of the selected memory cell array block.

Abstract: A data read circuit and method for use in a semiconductor memory device that has a memory cell array are provided. The circuit includes a selector for selecting a unit cell within the memory cell array in response to an address signal; a clamping unit for supplying a clamp voltage having a level for a read operation to a bit line of the selected unit cell in response to a clamp control signal; a precharge unit for precharging a sensing node to a voltage having a power source level in response to a control signal of a first state in a precharge mode, and compensating through the sensing node for a reduced quantity of current at the bit line in response to a control signal of a second state in a data sensing mode; and a sense amplifier unit for comparing a level of the sensing node with a reference level, and for sensing data stored in the selected unit cell.

Abstract: A redundancy circuit in a semiconductor memory device having a multiblock structure in which a memory cell array is classified into a plurality of memory cell blocks, an integrated redundancy circuit having a plurality of fuse boxes for storing, per block, addresses of defective memory cells provided in the plurality of memory cell blocks, the plurality of fuse boxes being connected to the common precharge unit and being selectively activated in response to a block distinction selection signal.

Abstract: A local column decoder circuit for electrically connecting data lines with bit lines in a semiconductor memory device, reducing a speed delay in reading and writing data and reducing the size of the semiconductor memory device. The local column decoder circuit includes a plurality of gate circuits for combining a first decoding signal for selecting a bit line with a second decoding signal for selecting a column group, and outputting a switching control signal for selecting a bit line of a corresponding column group; and a plurality of bit line selectors each for connecting the bit line of a corresponding column group among numerous column groups with a corresponding data line among numerous data lines in response to the switching control signal outputted from the plurality of gate circuits.

Abstract: An integrated circuit that is capable of being burn-in tested with an AC stress and a testing method using the same are provided. The integrated circuit includes an address transforming means and a data generating means. The address transforming means transforms the addresses of the memory device selected and generates an address signal responsive to a clock signal. The data generating means generates a data signal that alternates between a first state and a second state responsive to the clock signal and provides the data signal to the selected memory device. The integrated circuit includes a switch for coupling the test supply line to the normal supply line during testing and intercepting the test supply line from the normal supply line during normal operations responsive to a control signal. The integrated circuit of the present invention allows a wafer burn-in test by sequentially and repeatedly applying the AC stress to all the memory devices.

Abstract: A semiconductor memory device employs a power supply system in which a first power supply voltage supplied to a cell area is separated from a second power supply voltage supplied to a peripheral circuit area. Particularly, during a wafer burn-in test operation mode, the first power supply voltage supplied to the cell area is higher than the second power supply voltage supplied to the peripheral circuit area. If a wafer burn-in test operation is performed under the second power supply system, a DC current path formed by a latch-up phenomenon of a memory cell can be shut off.

Abstract: In a mode entrance control circuit and a mode entering method to stably enter a semiconductor memory device into a predetermined operating mode only when insensitive to a change of a process, temperature, or voltage, etc., and simultaneously satisfying a constant entrance condition, the mode entrance control circuit includes an operation control part for generating an operation enable signal when a first voltage applied through a first pad is over a first determination voltage, a voltage division part for dividing a second voltage applied through a second pad to generate a trimming reference voltage, and a mode entrance signal generating part operated in response to the operation enable signal, for comparing a level of an applied fixed reference voltage with a level of the trimming reference voltage, and for generating a mode entrance enable signal to allow the semiconductor memory device to enter into a predetermined mode.

Abstract: A semiconductor memory device is provided to generate a series of pulse signals in response to the activation of an internal chip select signal from an internal chip select buffer when an external chip select signal transitions from an inactive state to an active state. With this configuration, a chip select output time (tco) is more reduced as compared to prior arts. Further, the chip select output time is reduced to be equal to an address access time (tAA) because a designer can control the chip select output time. As a result, the whole access time of the semiconductor memory device can be reduced.

Abstract: A layout method is provided for a latch-up prevention circuit of a semiconductor memory device which includes the steps of: arranging a cell array at substantially the middle of the device; placing peripheral circuits next to both sides of the cell array; placing a plurality of pads on both sides of the cell array between the peripheral circuits and both edges of the device; and arranging guard rings beneath the plurality of pads. The layout method further includes a plurality of ESD protection transistors disposed axially along the direction as the plurality of pads between the plurality of pads and an edge of the device. And each of guard ring is a NWELL guard ring, and connected to a supply voltage and ground.

Abstract: An internal power voltage generating circuit of a semiconductor memory device for decreasing electric power consumption during a long cycle operation and for minimizing an internal power voltage drop caused by peak current consumption during a short cycle operation preferably includes a reference voltage generator for generating reference voltages, a pulse generator for generating an address shift detecting signal in response to a control signal, and at least one driver stage for generating an internal power voltage in response to a normal enable signal and the address shift detecting signal. A method for controlling an internal power voltage generator preferably includes preparing current sinks as a plurality of current sink paths to operate the driver stage that generates the internal power voltage and controlling one current sink path out of the plurality of current sink paths with an active operation-detecting signal.

Abstract: A semiconductor memory device employs a power supply system in which a first power supply voltage supplied to a cell area is separated from a second power supply voltage supplied to a peripheral circuit area. Particularly, during a wafer burn-in test operation mode, the first power supply voltage supplied to the cell area is higher than the second power supply voltage supplied to the peripheral circuit area. If a wafer burn-in test operation is performed under the second power supply system, a DC current path formed by a latch-up phenomenon of a memory cell can be shut off.

Abstract: A semiconductor memory device is provided to generate a series of pulse signals in response to the activation of an internal chip select signal from an internal chip select buffer when an external chip select signal transitions from an inactive state to an active state. With this configuration, a chip select output time (tco) is more reduced as compared to prior arts. Further, the chip select output time is reduced to be equal to an address access time (tAA) because a designer can control the chip select output time. As a result, the whole access time of the semiconductor memory device can be reduced.

Abstract: An integrated circuit that is capable of being burn-in tested with an AC stress and a testing method using the same are provided. The integrated circuit includes an address transforming means and a data generating means. The address transforming means transforms the addresses of the memory device selected and generates an address signal responsive to a clock signal. The data generating means generates a data signal that alternates between a first state and a second state responsive to the clock signal and provides the data signal to the selected memory device. The integrated circuit includes a switch for coupling the test supply line to the normal supply line during testing and intercepting the test supply line from the normal supply line during normal operations responsive to a control signal. The integrated circuit of the present invention allows a wafer burn-in test by sequentially and repeatedly applying the AC stress to all the memory devices.