Abstract: A method and apparatus to control a voltage conversion mode in a voltage converter are provided. The apparatus to control a voltage conversion mode includes: a voltage converter which converts an input voltage to an output voltage and having a plurality of voltage conversion modes; an input sensor which detects an input current value that is input to the voltage converter from a voltage source; an output sensor which detects an output current value that is output to a load from the voltage converter; and a controller which determines a power efficiency of the voltage converter based on the input and output current values and which switches between the voltage conversion modes of the voltage converter according to the detected power efficiency. Accordingly, an efficiency of voltage conversion is maximized, and a usage time of a mobile device can be lengthened.

Abstract: The invention relates to an electronic device (5) in the form of a flexible multilayer film body, in particular an RFID transponder, and to a rectifier (52) for such an electronic device. The rectifier (52) has at least two organic diodes or organic field effect transistors each having at least one electrical functional layer composed of a semiconducting organic material. The rectifier (52) furthermore has two or more charging or charge-reversal capacitors which are connected up to the two or more organic diodes or organic field effect transistors in such a way that the charging or charge-reversal capacitors can be charged via different current paths.

Abstract: The objective of the present invention is to obtain a vehicle electric-power conversion apparatus in which high-efficiency rectification operation can be realized, by detecting in real time a change, due to a fluctuation in a load, in a phase at which a switching element is turned on/off and by changing the phase at which the switching element is turned on/off, in response to the change. A diode-on timing and a diode-off timing corresponding to the diode conduction state of a diode connected in parallel with a switching element are detected; the values of rotor-position signals corresponding to the timings are sequentially stored; based on the stored values of rotor-position signals, a switching-element-on timing and a switching-element-off timing are calculated; and based on the timings, a gate command signal for the switching element is created.

Abstract: A mechanism for using electrical fuses (eFuses) to store phase-locked loop (PLL) configuration data are provided. With the mechanism, a portion of the eFuses present in the integrated circuit are reserved for the PLL configuration data. Upon power up, a power up controller and eFuse controller direct the sensing and serial transfer of the data in the portion of eFuses to the PLL under the reference clock. When the transfer is complete, the power up controller directs the PLL logic to load the configuration data and start. The mechanism of the present invention allows manufacturing to tailor the PLL configuration on a given device based on the characteristics of that device and its intended usage. Thus, the same PLL may be used in the same or different architectures to perform different operations based on the configuration data passed into the PLL from the eFuses.

Abstract: A memory structure, includes: an array of individual memory cells arranged in a network of bit lines and word lines, each individual memory cell further comprising a resistive memory device that is capable of being programmed to a plurality of resistance states, each of the resistive memory devices coupled to one of the bit lines at a first end thereof; a rectifying element in series with each of the resistive memory devices at a second end thereof; an access transistor associated with each of the individual memory cells, the access transistors activated by a signal applied to a corresponding one of the word lines, with each access transistor connected in series with a corresponding rectifying element; and a common connection configured to short neighboring rectifying devices together along a word line direction, in groups of two or more.

Abstract: In one embodiment, a read-only memory (ROM) is provided that includes: a plurality of word lines; a plurality of bit lines; a plurality of memory cell transistors arranged in rows corresponding to the word lines such that if a word line is asserted the corresponding memory cell transistors are conducting, the memory cell transistors also being arranged in columns corresponding to the bit lines; wherein each column of memory cell transistors is arranged into column groups, each column group including an access transistor coupled to the corresponding bit line, the remaining transistors in the column group being coupled in series from the access transistor to a last transistor in the column group, the last transistor in the column group being coupled to a voltage node.

Abstract: A ferroelectric capacitor includes: a ferroelectric film, and a lower electrode and an upper electrode interposing the ferroelectric film, wherein the ferroelectric film includes a first ferroelectric layer of ferroelectric material having a perovskite type crystal structure expressed by a general formula ABO3 formed by a metal organic chemical vapor deposition method, a second ferroelectric layer of ferroelectric material in which a part of B site element in ferroelectric material having a perovskite type crystal structure expressed by a general formula ABO3 is replaced with Nb, and a third ferroelectric layer of ferroelectric material having a perovskite type crystal structure expressed by a general formula ABO3 formed by a sol-gel method, which are sequentially laminated from the side of the lower electrode.

Abstract: An over-driven access method and device for ferroelectric memory. When accessing the data stored in a ferroelectric memory, the invention further provides an over-driven current to slightly reduce/raise the voltages in bit lines BL and BL? to further enlarge the voltage difference therebetween after having raised the plate-line /bit-line voltage using the plate-line /bit-line driven method.

Abstract: A method and apparatus is disclosed for sensing the resistance state of a Programmable Conductor Random Access Memory (PCRAM) element using complementary PCRAM elements, one holding the resistance state being sensed and the other holding a complementary resistance state. A sense amplifier detects voltages discharging through the high and low resistance elements to determine the resistance state of an element being read.

Abstract: Circuit arrays having cells with combinations of transistors and nanotube switches. Under one embodiment, cells are arranged as pairs with the nanotube switching elements of the pair being cross coupled so that the set electrode of one nanotube switching element is coupled to the release electrode of the other and the release electrode of the one nanotube switching element being coupled to the set electrode of the other. The nanotube articles are coupled to the reference line, and the source of one field effect transistor of a pair is coupled to the set electrode to one of the two nanotube switching elements and the source of the other field effect transistor of the pair is coupled to the release electrode to the one of the two nanotube switching elements.

Abstract: A memory cell comprises a wordline, a first digital inverter with a first input and a first output, and a second digital inverter with a second input and a second output. Moreover, the memory cell further comprises a first feedback connection connecting the first output to the second input, and a second feedback connection connecting the second output to the first input. The first feedback connection comprises a first resistive element and the second feedback connection comprises a second resistive element. What is more, each digital inverter has an associated capacitance. The memory cell is configured such that reading the memory cell includes applying a read voltage pulse to the wordline. In addition, the first and second resistive elements are configured such that the first and second feedback connections have resistance-capacitance induced delays longer than the applied read voltage pulse.

Abstract: A memory cell includes double-gate first and second access devices configured to selectively interconnect cross-coupled inverters with true and complementary bit lines. Each access device has a first gate connected to a READ word line and a second gate connected to a WRITE word line. During a READ operation, the first and second access devices are configured to operate in a single-gate mode with the READ word line “ON” and the WRITE word line “OFF” while the double-gate pull-down devices are configured to operate in a double gate mode. During a WRITE operation, the first and second access devices are configured to operate in a double-gate mode with the READ word line “ON” and the WRITE word line also “ON.

Abstract: Apparatus and methods are disclosed that enable writing data on, and reading data of, multi-state elements having greater than two states. The elements may be made of magnetoplastic and/or magnetoelastic materials, including, for example, magnetic shape-memory alloy or other materials that couple magnetic and crystallographic states. The writing process is preferably conducted through the application of a magnetic field and/or a mechanical action. The reading process is preferably conducted through atomic-force microscopy, magnetic-force microscopy, spin-polarized electrons, magneto-optical Kerr effect, optical interferometry or other methods, or other methods/effects. The multifunctionality (crystallographic, magnetic, and shape states each representing a functionality) of the multi-state elements allows for simultaneous operations including read&write, sense&indicate, and sense&control.

Abstract: An MTJ pattern layout for a memory device is disclosed that includes two CMP assist features outside active MTJ device blocks. A first plurality of dummy MTJ devices is located in two dummy bands formed around an active MTJ device block. The inner dummy band is separated from the outer dummy band by the MTJ ILD layer and has a MTJ device density essentially the same as the MTJ device block. The outer dummy band has a MTJ device density at least 10% greater than the inner dummy band. The inner dummy band serves to minimize CMP edge effect in the MTJ device block while the outer dummy band improves planarization. A second plurality of dummy MTJ devices is employed in contact pads outside the outer dummy band and is formed between a WL ILD layer and a BIT ILD layer thereby minimizing delamination of the MTJ ILD layer.

Abstract: A magnetic random access memory includes a bit line running in a first direction, a first word line running in a second direction different from the first direction, and a memory element having a magnetoresistive effect element including a fixed layer having a fixed magnetization direction, a recording layer having a reversible magnetization direction, and a nonmagnetic layer formed between the fixed layer and the recording layer, the magnetization directions in the fixed layer and the recording layer being perpendicular to a film surface, and a heater layer in contact with the magnetoresistive effect element, the memory element being connected to the bit line, and formed to oppose a side surface of the first word line such that the memory element is insulated from the first word line.

Abstract: A memory structure, includes: an array of individual memory cells arranged in a network of bit lines and word lines, each individual memory cell further comprising a resistive memory device that is capable of being programmed to a plurality of resistance states, each of the resistive memory devices coupled to one of the bit lines at a first end thereof; a rectifying element in series with each of the resistive memory devices at a second end thereof; an access transistor associated with each of the individual memory cells, the access transistors activated by a signal applied to a corresponding one of the word lines, with each access transistor connected in series with a corresponding rectifying element; and a common connection configured to short neighboring rectifying devices together along a word line direction, in groups of two or more.

Abstract: An architecture, and its method of formation and operation, containing a high density memory array of semi-volatile or non-volatile memory elements, including, but not limited to, programmable conductive access memory elements. The architecture in one exemplary embodiment has a pair of semi-volatile or non-volatile memory elements which selectively share a bit line through respective first electrodes and access transistors controlled by respective word lines. The memory elements each have a respective second electrode coupled thereto which in cooperation with the bit line access transistors and first electrode, serves to apply read, write and erase signals to the memory element.

Abstract: A PCRAM memory device having a chalcogenide glass layer, preferably comprising antimony selenide having a stoichometric formula of about Sb2Se3, and a metal-chalcogenide layer and methods of forming such a memory device.

Abstract: A memory device is provided. The memory device includes a memory layer and a fixed-magnetization layer. The memory layer retains information based on a magnetization state of a magnetic material. The fixed-magnetization layer is formed on the memory layer through an intermediate layer made of an insulating material. The information is recorded on the memory layer with a change in a magnetization direction of the memory layer caused by injecting a spin-polarized electron in a stacked direction. A level of effective demagnetizing field, which is received by the memory layer, is smaller than a saturation-magnetization level of magnetization of the memory layer.

Abstract: A tunnel magnetic resistive element forming a magnetic memory cell includes a fixed magnetic layer having a fixed magnetic field of a fixed direction, a free magnetic layer magnetized by an applied magnetic field, and a tunnel barrier that is an insulator film provided between the fixed and free magnetic layers in a tunnel junction region. In the free magnetic layer, a region corresponding to an easy axis region having characteristics desirable as a memory cell is used as the tunnel junction region. A hard axis region having characteristics undesirable as a memory cell is not used as a portion of the tunnel magnetic resistive element.

Abstract: We describe a CPP MTJ MRAM element that utilizes transfer of spin angular momentum as a mechanism for changing the magnetic moment direction of a free layer. The device includes a tunneling barrier layer of MgO and a non-magnetic CPP layer of Cu or Cr and utilizes a novel free layer comprising a thin layer of Ta or Hf sandwiched by layers of CoFeB. The device is characterized by values of DR/R between approximately 95% and 105%.

Abstract: The present invention relates to a memory cell including a first reference layer having a first magnetization with a first magnetization direction and a second reference layer having a second magnetization with a second magnetization direction substantially perpendicular to the first magnetization direction. A storage layer is disposed between the first reference layer and second reference layer and has a third magnetization direction about 45° from the first magnetization direction and about 135° from the second magnetization direction when the memory cell is in a first data state, and a fourth magnetization direction opposite the third magnetization direction when the memory cell is in a second data state.

Abstract: An embodiment of the present invention includes a multi-state current-switching magnetic memory element having a magnetic tunneling junction (MTJ), for storing more than one bit of information. The MTJ includes a fixed layer, a barrier layer, and a non-uniform free layer. In one embodiment, having 2 bits per cell, when one of four different levels of current is applied to the memory element, the applied current causes the non-uniform free layer of the MTJ to switch to one of four different magnetic states. The broad switching current distribution of the MTJ is a result of the broad grain size distribution of the non-uniform free layer.

Abstract: Techniques for attaining high performance magnetic memory devices are provided. In one aspect, a magnetic memory device comprising one or more free magnetic layers is provided. The one or more free magnetic layers comprise a low magnetization material adapted to have a saturation magnetization of less than or equal to about 600 electromagnetic units per cubic centimeter. The device may be configured such that a ratio of mean switching field associated with an array of non-interacting magnetic memory devices and a standard deviation of the switching field is greater than or equal to about 20. The magnetic memory device may comprise a magnetic random access memory (MRAM) device. A method of producing a magnetic memory device is also provided.

Abstract: The present invention relates generally to integrated circuits, to methods for manufacturing integrated circuits, and to integrated memory arrays.

Abstract: Provided are a capacitorless dynamic random access memory (DRAM) and a method of manufacturing and operating the capacitorless DRAM. The capacitorless DRAM includes a substrate having a first dopant region formed on the upper part thereof, a first protrusion unit formed on the substrate, a first gate and a second gate formed on the substrate on both sides of the first protrusion unit, having a height lower than the first protrusion unit, and an insulating material layer interposed between the substrate and the first and second gates and between the first protrusion unit and the first and second gates, wherein a second dopant region is formed on the upper part of the first protrusion unit.

Abstract: A memory page boosting method, device and system for boosting unselected memory cells in a multi-level cell memory cell is described. The memory device includes a memory array of multi-level cell memory cells configured to store a first portion of logic states and a second portion of logic states. When programming the first portion of logic states, a first boosting process is applied to unselected memory cells and when programming the second portion of logic states, a second boosting process is applied to unselected memory cells.

Abstract: A nonvolatile static random access memory (SRAM) device includes a pair of cross-coupled, complementary metal oxide semiconductor (CMOS) inverters configured as a storage cell for a bit of data and a pair of magnetic spin transfer devices coupled to opposing sides of the storage cell. The magnetic spin transfer devices are configured to retain the storage cell data therein following removal of power to the SRAM device, and are further configured to initialize the storage cell with the retained data upon application of power to the SRAM device.

Abstract: A nonvolatile semiconductor memory according to an aspect of the invention includes memory cell arrays including plural cell units, a power supply pad disposed on one end in a first direction of the memory cell arrays, and page buffers disposed in the first direction of the memory cell arrays. The nonvolatile semiconductor memory also includes plural bit lines which are disposed on the memory cell arrays while extending in the first direction and a first power supply line which is disposed on the plural bit lines on the memory cell arrays to connect the power supply pad and the page buffers.

Abstract: With this flash memory, because a plurality of memory blocks are formed on a surface of a single P-type well, a layout area can be made small. Further, when erasing data for a memory block to be erased, a voltage of the P-type well is applied to all word lines of a memory block to be not erased. Consequently, the voltage of the P-type well and the voltage of all word lines of the memory block to be not erased change at the same time. With this, it is possible to prevent a threshold voltage for the memory block to be not erased from changing.

Abstract: A single-poly EEPROM memory device comprises source and drain regions in a semiconductor body, a floating gate overlying a portion of the source and drain regions, which defines a source-to-floating gate capacitance and a drain-to-floating gate capacitance, wherein the source-to-floating gate capacitance is substantially greater than the drain-to-floating gate capacitance. The source-to-floating gate capacitance is, for example, at least about three times greater than the drain-to-floating gate capacitance to enable the memory device to be electrically programmed or erased by applying a potential between a source electrode and a drain electrode without using a control gate.

Abstract: A nonvolatile memory structure with pairs of serially connected select transistors connected to the top and optionally to the bottom of NAND series strings of groups of the dual-sided charge-trapping nonvolatile memory cells for controlling connection of the NAND series string to an associated bit line. A first of the serially connected select transistors has an implant to make a threshold voltage of the implanted first serially connected select transistor different from a non-implanted second serially connected select transistor. The pair of serially connected top select transistors is connected to a first of two associated bit lines. Optionally, the NAND nonvolatile memory strings further is connected a pair of serially connected bottom select transistors that is connected to the second associated bit line.

Abstract: A method of programming a charge trap type non-volatile memory device includes applying a program pulse to a selected memory cell, applying a detrap pulse to the selected memory cell, and applying a program verify pulse to the memory cell. The charge trap type non-volatile memory device includes a memory cell array including a charge trap memory cell, and a high voltage generator for supplying a detrap pulse to the charge trap memory cell.

Abstract: Flash memory devices have a plurality of memory cells that can be erased and programmed. Performing a voltage verification check allows a for an appropriate state-change voltage to be applied to the flash memory device. The appropriate state-change voltage is determined though accessing a look-up table. Using an appropriate state-change voltage allows a cell to operate with more overall programming cycles.

Abstract: A method of detecting an under program cell includes detecting second memory cells of programmed first memory cells. A threshold voltage of the second memory cell is higher than a first verifying voltage. A third memory cell is detected in the second memory cells. A threshold voltage of the third memory cell is smaller than a second verifying voltage. A method of programming a cell in a non-volatile memory device includes performing an program operation on selected memory cells. First memory cells are detected in the memory cells on which the program operation is performed. A threshold voltage of the first memory cell is higher than a first verifying voltage. An under program cell is detected in the first memory cells. A threshold voltage of the under program cell is smaller than a second verifying voltage. The under program cell is then programmed.

Abstract: Provided is a test method of a NAND flash memory. The method includes programming a page of a selected memory block in the flash memory; accumulating a program result of the page; and repeating the programming of other pages and the accumulating of the program result of the other pages until all pages in the selected memory block are programmed.

Abstract: Embodiments of the invention provide a flash memory device that can improve the reliability of a reading operation by minimizing a variation in the threshold voltage distribution that occurs due to coupling between cells, and a method of driving the flash memory device. In an embodiment of the invention, the method of driving the flash memory includes: performing an erasing operation on memory cells; after the performing the erasing operation, performing a post-programming operation to control a threshold voltage of the memory cells; and after performing the post-programming operation, performing a main programming operation on the memory cells, wherein the performing of the post-programming operation comprises increasing the threshold voltage of the memory cells in an erased state, thereby reducing a difference in the threshold voltage between the memory cells in the erased state and the memory cells in the programmed state.

Abstract: A method of reading data in a non-volatile memory device includes providing a plurality of blocks and a plurality of bit lines, each block having a plurality of memory cells, each block coupled to at least one bit line. Frst and second bit lines are discharged to be at a low level, the first bit line coupled to a first block, the second bit line coupled to a second block. A read voltage is applied to a first word line coupled to a memory cell to be read in the first block. A pass voltage is applied to a second word line coupled to a memory cell not to be read in the first block. The first bit line coupled to the memory cell to be read is precharged to a high level after applying the read voltage to the first word line and the pass voltage to the second word line. A voltage level of the first bit line is evaluated. Data stored in the memory cell to be read is sensed in accordance with the evaluated voltage level of the first bit line.

Abstract: A memory device including a plurality of memory cells, each with a control gate NMOS transistor sharing a floating gate with a program/erase PMOS transistor which is, in turn, connected in series with an access PMOS transistor. The memory cells are formed in a common N-Well formed in a P-substrate, the NMOS transistor being formed in a p-doped pocket or base. The program/erase PMOS includes a gate, and first and second P+ doped regions formed in the N-Well, wherein the first P+ region is electrically connected to a corresponding bit line. The access PMOS includes a gate, and first and second P+ regions formed within the N-Well, wherein the first P+ region is electrically connected to the second P+ region of the program/erase PMOS, and the gate is electrically connected to a corresponding word line.

Abstract: Erasing is performed with respect to a nonvolatile memory cell without causing depletion halfway therethrough. A control circuit for reversibly and variably controlling the threshold voltage of the nonvolatile memory cell by electrical erasing and writing controls an erase process of performing erasing to the plurality of nonvolatile memory cells assigned to one unit in an erase operation, a first write process of performing writing to the nonvolatile memory cell exceeding a pre-write-back level before a depletion level, and a second write process of performing writing to the nonvolatile memory cell exceeding a write-back level after the first write process. Since the occurrence of depletion is suppressed by successively performing the first write process with respect to the nonvolatile memory cells which may exceed the depletion level in the erase process, erasing can be performed to the nonvolatile memory cell without causing depletion halfway therethrough.

Abstract: An embodiment of a circuit includes an output buffer, a data interface which is at least in a position to transmit data, the data interface being coupled to an output of the output buffer, a command/address interface coupled to an input of the output buffer, a memory core coupled to the input of the output buffer, and a controller circuit configured to cause data stored within the output buffer to be output to the data interface, further configured to cause data stored within the memory core to be output to the input of the output buffer, so that the data is stored within the output buffer, and further configured to cause provision of data received at the command/address interface to the input of the output buffer, so that the data is stored within the output buffer.

Abstract: A semiconductor memory having a plurality of memory cells coupled to bit lines includes a bit line selecting circuit, a latch circuit, and a switching circuit. The bit line selecting circuit is disposed in a cell area where the memory cells are formed. The bit line selecting circuit is configured to select one of the bit lines in response to a first control signal. The latch circuit is disposed in a surrounding circuit area. The latch circuit is configured to perform a program operation or a read operation on the memory cells corresponding to the bit line selected by the bit line selecting circuit. The switching circuit is disposed in the surrounding circuit area, and is coupled between the bit line selecting circuit and the latch circuit. The switching circuit is configured to switch between the bit line selecting circuit and the latch circuit in response to a second control signal.

Abstract: A latch structure includes a first inverter that includes a first PMOS transistor and a first NMOS transistor, and a second inverter that includes a second PMOS transistor and a second NMOS transistor, receives an output signal of the first inverter, and outputs an input signal to the first inverter. The sources of the first and second transistors of the same type are connected to a common straight source line.

Abstract: Embodiments of the present invention include a data output circuit that can read data in parallel from a plurality of latches in a pipeline circuit. Even-numbered data and odd-numbered data are simultaneously output over a single clock cycle, and are then converted into DDR data and are then serially output. By moving data in this manner, embodiments of the invention can reduce the number of necessary control signals by as much as 50% over conventional data output circuits.

Abstract: Providing distinction between overlapping threshold levels of one or more multi-cell memory devices is described herein. By way of example, a system can include a sensing component that can measure a level associated with a first memory cell. The system can also include a comparison component that can compare the measured level associated with the first memory cell level to non-overlapping threshold levels, wherein such measurement can be used to determine a unique bit level associated with a second memory cell. By way of further example, methodologies are described for accurately measuring a bit level of a first cell of a dual-cell memory device, by comparing a second cell value to non-overlapping threshold values, as measured with respect to the second reference point.

Abstract: A semiconductor memory device and a control signal generating method thereof. The semiconductor memory device may include a voltage range detector configured to generate a voltage detecting signal corresponding to a range of a level of an external power voltage. A control signal generating portion may be used to generate a control signal corresponding to the range of the level of the external power voltage responsive to the voltage detecting signal. As a result, the semiconductor memory device can perform an operation for satisfying an access time characteristic according to a specification responsive to the control signal.

Abstract: A voltage generating circuit for a semiconductor memory apparatus according includes a data logic voltage generating unit that, when a data output unit outside a semiconductor memory apparatus outputs low-level data, generates an internal data logic voltage at the same potential level as the low-level data in response to an on-die termination signal. In addition, a reference voltage generating circuit for a semiconductor memory apparatus that uses the voltage generating circuit includes a reference voltage generating unit that can be configured to generate a reference voltage at an average potential level between a maximum potential and a minimum potential of input data.

Abstract: A write driver of a semiconductor memory device over drives a local input/output line at a write operation in order to transmit data provided in a global input/output line to a core area at a stable voltage level. Therefore the write driver charges a stable voltage level corresponding to data inputted at the write operation in a cell capacitor. The write driver includes a pull-up/pull-down driver for pull-up/pull-down driving a second data line depending on data loaded on a first data line, a pulse generation circuit for generating pull-up over driving pulses activated for a predetermined time period at the initial time of an interval that the second data line is pull-up driven, and an over driver for pull-up driving the second data line by an over driving voltage higher than a pull-up voltage of the pull-up/pull-down driver in response to the pull-up over driving pulses.

Abstract: The present invention relates to methods and apparatus for improving the stability of static random access memory (SRAM) cells by using boosted word lines. Specifically, a boosted word line voltage (Vdd?) is applied to the word line of a selected SRAM cell, while such a boosted word line voltage (Vdd?) is sufficiently higher than the power supply voltage (Vdd) of the SRAM cell so as to improve the cell stability to a desired level. Specifically, a specific boosted word line voltage is predetermined for each SRAM cell based on the specific cell configuration, by using a circuit simulation program, such as the BERKELEY-SPICE simulation program. A boost voltage generator is then used to apply the predetermined boosted word line voltage to the selected SRAM cell.

Abstract: According to an aspect of one embodiment, it is provided that semiconductor memory device determining a data read time required to read data from a memory cell by an operation to read a replica cell to which a replica bit line having a load equivalent to a bit line to be connected to the memory cell and a replica word line are connected, the semiconductor memory device comprising: a write control signal generating unit that includes logic gates coupled in multi stages for receiving an input of a replica word line activating signal generated in response to a driving signal for driving the replica word line, the write control signal generating unit generating a write control signal to determine a data write time required to write data in the memory cell based on the replica word line activating signal.