Abstract: A search system is obtained by combining a TCAM and a search engine not using the TCAM. The search engine not using the TCAM is constructed using a general-purpose memory cell structure, and includes a different-sized memory spaces each corresponding to an effective bit length of search target data.

Abstract: A semiconductor device includes a plurality of memory arrays and a plurality of memory array control circuits. Each of the plurality of memory array control circuits includes a read/write control circuit for controlling a read/write operation for the memory array, and a selection circuit for selecting and activating the memory array based on a clock signal and an output signal from the read/write control circuit.

Abstract: A search system is obtained by combining a TCAM and a search engine not using the TCAM. The search engine not using the TCAM is constructed using a general-purpose memory cell structure, and includes a different-sized memory spaces each corresponding to an effective bit length of search target data.

Abstract: To provide a semiconductor storage device capable of performing a search of the next data while performing a search of certain data. A first comparator compares data output to a bit line from a memory cell with first search data by activating a word line. A second comparator compares data output to a bit line from the memory cell with second search data by activating a word line. Data output to a bit line by the activation of one word line is input to both the first comparator and second comparator.

Abstract: A semiconductor device includes a plurality of memory arrays and a plurality of memory array control circuits. Each of the plurality of memory array control circuits includes a read/write control circuit for controlling a read/write operation for the memory array, and a selection circuit for selecting and activating the memory array based on a clock signal and an output signal from the read/write control circuit.

Abstract: To provide a semiconductor storage device capable of performing a search of the next data while performing a search of certain data. A first comparator compares data output to a bit line from a memory cell with first search data by activating a word line. A second comparator compares data output to a bit line from the memory cell with second search data by activating a word line. Data output to a bit line by the activation of one word line is input to both the first comparator and second comparator.

Abstract: A storage device is connected to a large-capacity low-speed memory, and divides a packet received via a network into a plurality of segments for storage. The storage device includes a small-capacity high-speed memory. A selector writes the first predetermined number of segments in the packet to the small-capacity high-speed memory, and subsequent segments to the large-capacity low-speed memory. Accordingly, regardless of from what queue a segment is read out in a segment read mode, occurrence of wasteful time in packet transfer can be prevented, and the capacity of the small-capacity high-speed memory can be reduced even when the number of queues increases.

Abstract: A shift register which outputs a delay control signal for a delay line is made controllable at a test mode by a TEST MODE address buffer receiving an external address as a control signal and a phase comparator. Thus whether the delay of the delay line is correctly controlled or not can be confirmed through observation of an internal clock signal int. CLK output from an output buffer at the test and an external clock signal ext. CLK.

Abstract: In a DLL circuit between a phase comparator and a digital filter there is provided a signal switching portion preventing control signals UP and DOWN from being transmitted after a clock enable signal extCKE is activated and before a predetermined period of time elapses. Thus after a semiconductor device returns from a power down mode and before a predetermined period of time elapses it continues to stop updating an amount of delay of a delay line. Thus before an internal power supply potential stabilizes the delay line does not have a varying amount of delay and as a result the semiconductor device can output data at a timing free of significant fluctuation.

Abstract: An impedance adjustment circuit generates an internal impedance adjustment signal and an impedance adjustment entry signal based on an externally applied impedance control signal. A data processing circuit decodes the internal impedance adjustment signal in synchronization with an internal clock signal to generate an output buffer drive signal of 5 bits. When the output buffer drive signal is applied to an output circuit of the succeeding stage as well as to an output replica circuit in a DLL circuit, the impedance of the output replica circuit is adjusted following adjustment of the output impedance.

Abstract: An impedance adjustment circuit generates an internal impedance adjustment signal and an impedance adjustment entry signal based on an externally applied impedance control signal. A data processing circuit decodes the internal impedance adjustment signal in synchronization with an internal clock signal to generate an output buffer drive signal of 5 bits. When the output buffer drive signal is applied to an output circuit of the succeeding stage as well as to an output replica circuit in a DLL circuit, the impedance of the output replica circuit is adjusted following adjustment of the output impedance.

Abstract: In a DLL circuit between a phase comparator and a digital filter there is provided a signal switching portion preventing control signals UP and DOWN from being transmitted after a clock enable signal extCKE is activated and before a predetermined period of time elapses. Thus after a semiconductor device returns from a power down mode and before a predetermined period of time elapses it continues to stop updating an amount of delay of a delay line. Thus before an internal power supply potential stabilizes the delay line does not have a varying amount of delay and as a result the semiconductor device can output data at a timing free of significant fluctuation.

Abstract: A DLL circuit includes a delay line having a configuration with delay stages receiving alternate complementary clock signals ECK and /ECK having an adjusted phase difference therebetween. A capacitor can be used to adjust the phase difference between signals ECK and /ECK to allow the delay line to provide an amount of delay varying minutely. Preferably, for a fast clock, delay adjustment starts with a shift register having an initial value providing an intermediate amount of delay, and for a slow clock, delay adjustment starts with the shift register having an initial value providing a minimal amount of delay. There can be provided a semiconductor device provided with a DLL circuit accommodating a fast clock with reduced jitter.

Abstract: A clock buffer includes: a comparator circuit comparing complementary clock signals CLK and /CLK with each other to output an internal clock signal used in a normal operation; a comparator circuit comparing a reference potential Vref and clock signal CLK with each other; and a comparator circuit comparing reference potential Vref and clock signal /CLK with each other. A phase comparator circuit compares the complementary clock signals with each other in respect to phase. An input/output buffer outputs an output of the phase comparator circuit to a data output terminal in a test mode. Therefore, there can be realized a test mode for performing efficient calibration of a measuring apparatus.

Abstract: A semiconductor memory device is provided with a static random access memory (SRAM) serving as a cache memory and a dynamic random access memory (DRAM) serving as a main memory. A bi-directional data transfer circuit is arranged for transfer of data blocks between the SRAM and the DRAM. A command register is provided for holding command data to set operation modes such as a data output mode of the memory device. The data output mode may include a transparent mode, a latched mode and a registered mode selected depending on a data combination at data input terminals of the memory device. An output circuit for providing a selected data output mode includes an output latch circuit for latching data on read data buses in response to clock signals, and an output buffer for outputting data from the output latches to a data output terminal.

Abstract: Serial write data of the burst length transmitted to a data bus are stored in parallel in latch circuits by a S/P data conversion circuit. In a memory cell array, one row of memory cells and four columns of memory cells are rendered active at the same time. Respective bit lines and latch circuits are connected by a sense amplifier I/O circuit. The write data of the burst length are written into the memory cell array at one time. The data of the bit length read out at one time from the memory cell array are converted into serial data by a P/S data conversion circuit to be transmitted to the data bus.

Abstract: A DLL circuit includes a delay line having a configuration with delay stages receiving alternate complementary clock signals ECK and /ECK having an adjusted phase difference therebetween. A capacitor can be used to adjust the phase difference between signals ECK and /ECK to allow the delay line to provide an amount of delay varying minutely. Preferably, for a fast clock, delay adjustment starts with a shift register having an initial value providing an intermediate amount of delay, and for a slow clock, delay adjustment starts with the shift register having an initial value providing a minimal amount of delay. There can be provided a semiconductor device provided with a DLL circuit accommodating a fast clock with reduced jitter.

Abstract: A semiconductor memory device includes a DRAM, an SRAM and a bi-direction transfer gate circuit provided between SRAM and DRAM. SRAM array includes a plurality of sets of word lines. Each set is provided in each row of SRAM array and each word line in each set is connected to a different group of memory cells of an associated row. An address signal for the SRAM and an address signal for the DRAM are separately applied to an address buffer. The semiconductor memory device further includes an additional function control circuit for realizing a burst mode and a sleep mode. A data transfer path from DRAM to the SRAM and a data transfer path from the SRAM to the DRAM are separately provided in the bi-directional transfer gate circuit. Data writing paths and data reading paths are separately provided in the DRAM array. By the above described structure, operation of the buffer circuit is stopped in the sleep mode, reducing power consumption.

Abstract: There are provided a memory controller, a plurality of memory modules, and an external data bus common to the plurality of memory modules. The plurality of memory modules each include a plurality of memory chips, a plurality of internal data buses connected between a corresponding memory chip and an input/output terminal, a logic chip, and a plurality of switch transistors each connected between a corresponding internal data bus and a corresponding input/output terminal to turn on/off in response to a control signal from the logic chip. The plurality of switch transistors in a memory module selected by the memory controller are turned on, and the plurality of switch transistors in the memory modules other than the selected memory module are turned off. Thus, the capacity of the memory modules may be increased while maintaining high-speed data transfer.

Abstract: A semiconductor memory device receives an external control signal repeatedly generated independently of an access to the memory device. The memory device includes an internal voltage generator for generating a desired internal voltage in response to the control signal. The internal voltage generator includes a charge pump circuit responsive to the control signal. The internal voltage may provide a negative voltage such as a substrate bias voltage, or may be a positive voltage boosted over an operating power supply voltage and used as a boosted word line drive signal. This scheme eliminates an oscillator for generating a repeated clock signal to the charge pump circuit, leading to reduced current consumption and reduced chip area for the semiconductor memory device.