Abstract: A synchronous dynamic random access memory capable of accessing data in a memory cell array therein in synchronism with a system clock from an external system such as a central processing unit (CPU).

Abstract: A semiconductor memory device stably operates over a wide range of the power supply voltage by including a power supply voltage level detector for generating detecting signals according to predetermined levels of the power supply voltage and an oscillator for generating a frequency-controlled oscillation pulse whose frequency is changeable according to the detecting signals. Thus, a boosting ratio of a boosting circuit, the refresh period of a refresh circuit and the substrate voltage of a substrate voltage generator can be adaptively changeable according to the variation of the power supply voltage.

Abstract: A synchronous dynamic random access memory capable of accessing data in a memory cell array therein in synchronism with a system clock from an external system such as a central processing unit (CPU).

Abstract: A burn-in enable circuit and burn-in test method of a semiconductor memory device are disclosed. A high voltage exceeding the external power voltage by a predetermined amount is applied to at least one of a plurality of pins normally used with a connected semiconductor memory chip to initiate a burn-in test mode. The burn-in test enable circuit senses this high voltage and causes the reset operation of word lines in the chip to become disabled. This allows for a high stress voltage to be applied to all access transistors in the chip simultaneously during a burn-in test for substantially the same amount of time. Therefore, burn-in time is substantially reduced and a reliable burn-in test is obtained.

Abstract: A semiconductor memory device stably operates over a wide range of the power supply voltage by including a power supply voltage level detector for generating detecting signals according to predetermined levels of the power supply voltage and an oscillator for generating a frequency-controlled oscillation pulse whose frequency is changeable according to the detecting signals. Thus, a boosting ratio of a boosting circuit, the refresh period of a refresh circuit and the substrate voltage of a substrate voltage generator can be adaptively changeable according to the variation of the power supply voltage.

Abstract: A semiconductor memory device using a clock of a constant period supplied from the exterior of a memory chip and a sense amplifier for reading out data from a memory cell designated by an address includes at least two different delay circuits for setting at least two delay time periods from the clock, a selecting circuit for receiving signals generated from the delay circuits and selecting one of said signals by a given control signal, and a data output buffer for receiving the data generated from the sense amplifier by a signal generated from the selecting circuit.

Abstract: The present invention relates to a semiconductor memory device, and more particularly to a dynamic random access memory for accomplishing high speed data access by supplying a plurality of row address strobe signals to a chip. A plurality of row address strobe signals are supplied to a plurality of pins, and each row address strobe signal is sequentially supplied with an active signal during a data access operation. Therefore, data in a plurality of memory cell arrays is accessed during one access cycle time. Thus, since a large number of random data are provided, the data access time decreases and the performance of a system can be greatly improved.

Abstract: A sense amplifier of a semiconductor memory device for performing a high-speed sensing operation. A sensing node SAN and SAN of the sense amplifier is precharged to a power voltage level and during a sensing operation, first and second clock signals which are shifted to the power voltage and a ground voltage level, respectively, are applied to the sense amplifier. Thus, a potential difference of the sensing node dependent on a precharge state of the power voltage level is generated quickly and sufficiently. Therefore, the high speed sensing operation and a fast access of data can be performed, thereby improving the performance of the semiconductor memory device.

Abstract: A data output buffer includes an output driving stage having a pair of parallel pull-up transistors and a pull-down transistor, a latch circuit for latching a pair of complementary signals, a second gate for gating the non-inverted output signal of the latch circuit in response to an external output enable signal and then supplying it to the gate of one pull-up transistor of the output driving state, a third gate also for gating the non-inverted output signal of the latch circuit in response to an external output enable signal, and a selective bootstrap circuit for driving the other pull-up transistor of the output driving stage. The output driving stage is driven to an external supply voltage when the external supply voltage is higher than a set voltage, and is driven to a boosted voltage when the external supply voltage is lower than the set voltage, determined by output signals from the second and third gates.

Abstract: A constant voltage generator of a semiconductor device includes an oscillator for generating an AC signal, a charge pump for pumping charge from a power voltage supply line by a predetermined pumping ratio in accordance with the AC signal of the oscillator, a charge storage capacitor for storing the pumped charge, and a voltage limiter for limiting the voltage across the charge storage capacitor at a predetermined voltage level, then outputting a constant voltage. According to the present invention, the charge of the storage capacitor is quickly stored, a constant voltage is obtained independent of a power source voltage, and the reference voltage output can be greater than the power source voltage.

Abstract: A semiconductor memory device includes an address transition detection circuit for detecting the state transition of address signals and generating a pulse having a predetermined pulse width, a precharge circuit for generating and equalizing a pair of input/output lines in response to the output pulse of the address transition detection circuit, address decoder circuit for decoding the address signals and generating an address selection signal, and a gate circuit connecting the pair of input/output lines to a selected pair of bit lines in response to the address selection signal of the address decoder circuit. In the device, the address decoder circuit has a signal delay characteristic for delaying signals from the state transition of the address signal until the completion of the precharge and equalization of the I/O lines.

Abstract: An output feedback control circuit for an integrated circuit (IC) device is disclosed which includes an I/O line sense amplifier for amplifying the weak signals read out from cells, a read driver for amplifying the output of the I/O line sense amplifier, an output latch/transmission block for latching or transmitting the output signals of the read driver, a precharge block for precharging the output node of the output latch/transmission block, and a state transition detecting block for generating feedback control clocks. If the circuit of the present invention is installed to the output terminal of an IC decive, the data latched at the output node can be maintained regardless of the intruding of an external noise until a precharge clock is generated at a new cycle. Further, the sense amplifier and the read driver are disabled after having amplified the input signals within a single cycle, and therefore, the DC power consumption can be prevented.