Samsung Electronics Co., Ltd.

Churoo Park

Hyun-Soon Jang

Ho-cheol Lee

Yun-Ho Choi

Si-Yeol Lee

Tae-jin Kim

Myung-Ho Kim

Chull-Soo Kim

Seung-Hun Lee

Seong-Ook Jung

Seung-hun Lee

Soo-In Cho

Moon-Hoi Son

Myung-chan Choi

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). The synchronous DRAM receives an external clock and includes a plurality of memory banks each including a plurality of memory cells and operable in either an active cycle or a precharge cycle, a circuit for receiving a row address strobe signal and latching a logic level of the row address strobe signal in response to the clock, an address input circuit for receiving an externally generated address selecting one of the memory banks, and a circuit for receiving the latched logic level and the address from the address input circuit and for outputting an activation signal to the memory bank selected by the address and an inactivation signals to unselected memory banks when the latched logic level is a first logic level, so that the selected memory bank responsive to the activation signal operates in the active cycle while the unselected memory banks responsive to the inactivation signals operate in the precharge cycle.

Multi-bank dynamic random access memory devices having all bank precharge capability

A circuit for testing a semiconductor memory device comprises a latency controller for controlling the latency of the external clock signal, an internal column address generator for generating a column address signal in the memory device, and a mode register for generating a mode signal. The circuit for testing semiconductor memory devices also includes a column address decoder for decoding the output address signal of the internal column address generator, a memory cell for reading or writing data, an input/output control unit for controlling the data input/output of the memory cell according to the output signal of the latency controller, a data input buffer, and a data output buffer. Further provided are a frequency multiplier for generating an internal clock signal having a frequency 'n' times the frequency of the external clock signal. By providing the above-mentioned improvements, the conventional test equipment can be used to test high frequency memory devices.

Method and circuit for testing a semiconductor memory device operating

Circuit in a semiconductor memory for programming operation modes of the

A method and apparatus for implementing a prefetch scheme in which a plurality of data are simultaneously read from memory cells of sequential addresses synchronized to an external signal and serially transferred from the memory cells to a temporary latch circuit which has a number of bits corresponding to the member of bits in the prefetch scheme. The bits in the temporary latch circuit are multiplexed and sequentially driven out of the memory device. The memory device includes a plurality of memory cells which are connected to an input/output line pair through a plurality of column select gates, each of which is controlled by an independent chip select line. A sense amplifier is connected to the input/output line pair for sensing and amplifying data from the input/output lines and to transmit data to the input/output lines. A data output buffer transfers the data from the sense amplifier to the outside of chip.

Column decoder for semiconductor memory device with prefetch scheme

Synchronous dram having a plurality of latency modes

An internal column address generation circuit generates an internal column address by utilizing an asynchronous counter. The circuit includes a column address buffer for synchronizing an initially received external address with an external system clock to generate the internal column address, and for synchronizing a counting bit output signal received at an internal input node with the external system clock to generate the internal column address; and an asynchronous counter connected to an output node of the column address buffer, for generating the bit output signal having the same or opposite phase as/to a phase of the internal column address received from the column address buffer, in response to a carry generation state.

Circuit for generating internal column address suitable for burst mode

A method for testing a plurality of data bits includes the steps of accepting the plurality of data bits at the test circuit, and comparing first and second data bits from the plurality of data bits to determine if the first and second data bits have a common data value. A first comparison signal is generated responsive to the comparison of the first and second data bits. The first comparison signal has a first logic state when the first and second data bits have a common data value and a second logic state when the first and second data bits have different data values. Third and fourth data bits from the plurality of data bits are compared to determine if the third and fourth data bits have a common data value. A second comparison signal is generated responsive to the comparison of the third and fourth data bits wherein the second comparison signal has the first logic state when the third and fourth data bits have a common data value and the second logic state when the third and fourth data bits have different data values.

Multi-bit test circuits for integrated circuit memory devices and

System for selecting one of a plurality of memory banks for use in an

A column redundancy circuit and method of a semiconductor memory device. The column redundancy circuit comprises a programming element for programming a repair column address; a comparing element for comparing the programmed repair column address with a column address inputted from outside to thereby generate a redundancy enable control signal according to result of the comparison; a decoding element for decoding the repair column address signal to thereby generate a decoding signal; and a redundancy column select element for compounding the decoding signal and a data input signal to thereby enable a redundancy column select signal.

Column redundancy circuit and method of semiconductor memory device

Semiconductor memory having a plurality of I/O buses

Disclosed is a semiconductor memory device with a block write function for reading and writing data in a unit of two bytes, which comprises a plurality of memory cell blocks for associating bits accessed in response to a column address to designate the upper one of the two bytes and bits accessed in response to a column address to designate the lower one of the two bytes, at least two column select lines enabled in response to same column addresses, and a control circuit for separately controlling the two column select lines, wherein the bits of the upper and lower bytes stored in the memory cell blocks are all outputted in response to the column addresses.

Semiconductor memory device and method for gating the columns thereof

A semiconductor memory device for processing data in synchronization with a system clock applied from the exterior includes a circuit for generating a write latency control signal, a circuit for generating one active information enlarged signal from a plurality of active information signals generated in response to a column related control signal supplied from the exterior, and a circuit for holding internal operations of a column address counter, a burst length counter and a data transfer switching circuit for a prescribed time in which the active information enlarged signal is in an active state.

Synchronous semiconductor memory device with a write latency control

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.

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Suwon, South Korea

Churoo Park