摘要:
A semiconductor memory device having high integration, low power consumption and high operation speed. The memory device includes a sense amplifier circuit having plural pull-down circuits and a pull-up circuit. A transistor constituting one of the plural pull-down circuits has a larger constant than that of a transistor constituting the other pull-down circuits, for example, a channel length and a channel width. The pull-down circuit having the larger constant transistor is activated earlier than the other pull-down circuits and the pull-up circuit, which are activated to conduct reading. The data line and the earlier driven pull-down circuit are connected by an NMOS transistor and the NMOS transistor is activated or inactivated to control the activation or inactivation of the pull-down circuit.
摘要:
A sense amplifier is constructed to reduce the occurrence of malfunctions in a memory read operation, and thus degraded chip yield, due to increased offset of the sense amplifier with further sealing down. The sense amplifier circuit is constructed with a plurality of pull-down circuits and a pull-up circuit, and a transistor in one of the plurality of pull-down circuits has a constant such as a channel length or a channel width larger than that of a transistor in another pull-down circuit. The pull-down circuit with a larger constant of a transistor is first activated, and then, the other pull-down circuit and the pull-up circuit are activated to perform the read operation.
摘要:
A timing control circuit DLY1 receives clock signal CKa with period T1 and activation signal ACT and outputs fine timing signal FT with delay of m*T1+tda measured from the clock signal where m denotes a non-negative integer and tda denotes delay in the analog delay element. The timing control circuit DLY1 comprises a coarse delay circuit CD and a fine delay circuit FD. The coarse delay circuit CD comprises a counter for counting a rising edge of the clock signal CKa after receiving activation signal ACT and outputs coarse timing signal CT with delay of m*T1 measured from a rising edge of the clock signal CKa. The fine delay circuit FD comprises a plurality of analog delay elements and outputs fine delay timing signal FT with delay of tda measured from the coarse timing signal CT. Variation in delay of timing signal is reduced.
摘要:
The semiconductor memory device according to the invention is provided with a first delay circuit block that generates a timing signal of a circuit block to be operated in column cycle time determined by an external input command cycle and a second delay circuit block the whole delay of which is controlled to be a difference between access time determined by an external clock and the latency and column cycle time. These delay circuit blocks are controlled so that the delay of each delay circuit is a suitable value in accordance with column latency and an operating frequency, and each delay is controlled corresponding to dispersion in a process and operating voltage and a change of operating temperature.
摘要:
The semiconductor memory device according to the invention is provided with a first delay circuit block that generates a timing signal of a circuit block to be operated in column cycle time determined by an external input command cycle and a second delay circuit block the whole delay of which is controlled to be a difference between access time determined by an external clock and the latency and column cycle time. These delay circuit blocks are controlled so that the delay of each delay circuit is a suitable value in accordance with column latency and an operating frequency, and each delay is controlled corresponding to dispersion in a process and operating voltage and a change of operating temperature.
摘要:
A semiconductor memory device having high integration, low consumption power and high operation speed compatible to each other including a sense amplifier circuit having plural pull-down circuits and a pull-up circuit, in which a transistor constituting one of plural pull-down circuits has a larger constant than that of a transistor constituting other pull-down circuits, for example, a channel length and a channel width, a pull-down circuit having a larger constant of the transistor in the plural pull-down circuits is precedingly activated and then another pull-down circuit and the pull-up circuit are activated to conduct reading and, further, the data line and the precedingly driven pull-down circuit are connected by an NMOS transistor and the NMOS transistor is activated or inactivated to control the activation or inactivation of the pull-down circuit.
摘要:
A DRAM capable of realizing reduced power consumption, high-speed operation, and high reliability is provided. A gate electrode configuring a memory cell transistor of the DRAM is composed of an n-type polysilicon film and a W (tungsten) film stacked thereon. A part of the polysilicon film is embedded in a trench formed in a silicon substrate in order to elongate the effective channel length of the memory cell transistor. The other part of the polysilicon film is located above the trench, and an upper surface thereof is located above a surface of the silicon substrate (p-type well). Therefore, distances between the W film and a source and drain (n-type semiconductor regions) are ensured.
摘要:
A semiconductor memory device having high integration, low power consumption and high operation speed. The memory device includes a sense amplifier circuit having plural pull-down circuits and a pull-up circuit. A transistor constituting one of the plural pull-down circuits has a larger constant than that of a transistor constituting the other pull-down circuits, for example, a channel length and a channel width. The pull-down circuit having the larger constant transistor is activated earlier than the other pull-down circuits and the pull-up circuit, which are activated to conduct reading. The data line and the earlier driven pull-down circuit are connected by an NMOS transistor and the NMOS transistor is activated or inactivated to control the activation or inactivation of the pull-down circuit.
摘要:
A substrate voltage control technique that prevents the operating speed from being decreased and suppresses a leakage current due to a lower threshold voltage with respect to a low voltage use. Since a center value of the threshold voltages is detected by plural replica MOS transistors, and a substrate voltage is controlled to control a center value of the threshold voltages, thereby making it possible to satisfy a lower limit of the operating speed and an upper limit of a leakage current of the entire chip. On the other hand, the substrate voltage is dynamically controlled during the operation of the chip, thereby making it possible to decrease the center value of the threshold voltages when the chip operates to improve the speed, and to increase the center value of the threshold voltages after the operation of the chip to reduce the leakage current of the entire chip.
摘要:
A substrate voltage control technique that prevents the operating speed from being decreased and suppresses a leakage current due to a lower threshold voltage with respect to a low voltage use. Since a center value of the threshold voltages is detected by plural replica MOS transistors, and a substrate voltage is controlled to control a center value of the threshold voltages, thereby making it possible to satisfy a lower limit of the operating speed and an upper limit of a leakage current of the entire chip. On the other hand, the substrate voltage is dynamically controlled during the operation of the chip, thereby making it possible to decrease the center value of the threshold voltages when the chip operates to improve the speed, and to increase the center value of the threshold voltages after the operation of the chip to reduce the leakage current of the entire chip.