Oki Electric Industry Co., Ltd.

Oki Electric Co., Ltd.

Satoru Tanoi

Tetsuya Tanabe

Yasuhiro Tanaka

Atsuhiko Okada

Yasuhiro Tokunaga

An amplifier includes a ground, first and second MOS transistors, a first resistive load and a supply voltage, which are connected in series in this order. A bias circuit provides first and second bias voltages to the gate electrodes of the first and second transistors, respectively. The bias circuit includes a third MOS transistor having its gate and drain electrode diode-connected. The drain electrode of the third transistor provides the first bias voltage of the amplifier. The bias circuit further includes fourth and fifth MOS transistors, and a second resistive load, which are connected in series in this order. The second resistive load is connected to the supply voltage. The fourth transistor has its gate electrode connected to the drain electrode of the third transistor. The fifth transistor has its gate and drain electrodes diode-connected. The drain electrode of the fifth transistor provides the second bias voltage.

Bias circuit for a wideband amplifier driven with low voltage

A semiconductor memory device has memory cells for storing data, sense amplifiers for amplifying the stored data, and cache cells in which the amplified data can be placed for quick recall. The cache cells can continue to hold data during memory-cell refresh cycles, permitting the cached data to be accessed quickly afterward. The cache cells may be coupled to column data lines that can be disconnected from the sense amplifiers, enabling memory cells to be refreshed while cache access is in progress. Write buffers may be provided so that when cache data are replaced, the old cache data can be copied back to the memory cells while the new cache data are being accessed.

Semiconductor memory with built-in cache

A semiconductor memory device has memory cells storing data, sense amplifiers for amplifying the stored data, and cache cells in which the amplified data can be placed for quick recall. The cache cells can continue to hold data during memory-cell refresh cycles, permitting the cached data to be accessed quickly afterward. The cache cells may be coupled to column-data lines that can be disconnected from the sense amplifiers, enabling memory cells to be refreshed while cache access is in progress. Write buffers may be provided so that when cache data are replaced, the old cache data can be copied back to the memory cells while the new cache data are being accessed.

Disclosed herein is a semiconductor device having a semiconductor memory circuit whose operation is tested in combination with an external test means to specify defective portions produced in a memory section of the semiconductor memory circuit and shorten the time necessary for its test. The present semiconductor device comprises a test pattern generator for generating a test pattern indicative of the type of test and an expected value estimated to be obtained by the test pattern in response to a command issued from the test means, the semiconductor memory circuit, which has a plurality of memory cells disposed in the form of a matrix with rows and columns and respectively store data therein and is activated based on the test pattern so as to output data in the respective memory cells every columns, a decision unit for comparing each output data with the expected value and outputting the result of comparison therefrom and a translation unit for converting the result of comparison into address data and outputting it to the external test means.

Semiconductor device having semiconductor memory circuit to be tested, method of testing semiconductor memory circuit and read circuit for semiconductor memory circuit

A semiconductor device that enables a reduction in power consumption and a stable operation, and which can be manufactured easily and with a high level of integration. In an invention exemplifying the present application, a sense circuit constituting a DRAM comprises a bit line pre-charge circuit, a pre-amplifier circuit PSA100 and a main amplifier circuit MSA100. The pre-amplifier circuit is provide with a switch circuit and an amplifier circuit. The switch circuit comprises a switch element provided between input/output terminals and a pre-sense node, and a switch element provided between input/output terminals and another pre-sense node. The amplifier circuit comprises MOS transistors and switch elements.

Semiconductor storage device

According to one aspect of the invention, a semiconductor memory has, as word lines, a layer of high-resistance signal lines that are paralleled in a separate layer by low-resistance signal lines. Each high-resistance signal line is divided into segments separated by gaps. Interconnections between the high- and low-resistance signal lines in each word line are aligned with the gaps in the high-resistance signal lines in the adjacent word lines. According to a second aspect of the invention, the low-resistance signal lines extend, from alternate directions, to approximately the midpoints of the high-resistance signal lines. The high-resistance signal lines are undivided, or are divided into only two segments apiece. The high- and low-resistance signal lines are interconnected at the midpoints, or at the midpoints and one end.

Semiconductor memory with improved word line structure

Semiconductor memory

There is provided a current amplifier and a data bus circuit using such a current amplifier capable of reducing input impedance with a smaller circuit area than the conventional so that high-speed operation of the data bus lines can be realized without a remarkable increase of the circuit area. The current amplifier includes first and second field effect transistors N11, N12 respectively provided between a pair of input terminals I, Ib and a first potential supply terminal Vcc, and third and fourth field effect transistors N13, N14 for supplying output power to a pair of output terminals O, Ob. The gate of the third field effect transistor is connected to the first input terminal and to the source of the first field effect transistor the gate of which is connected to the drain of the third field effect transistor, whereas the gate of the fourth field effect transistor is connected to the second input terminal and to the source of the second field effect transistor the gate of which is connected to the drain of the fourth field effect transistor.

Current amplifier and data bus circuit

A clock distributing circuit, that comprises a clock distribution output circuit for inputting an external clock, outputting a first clock that synchronizes with the external clock, and distributing the first clock to each of load circuits, and a distributed clock input circuit disposed on input stages of all or part of the load circuits and adapted for inputting the first clock and outputting a second clock that synchronizes with the input clock, wherein one of the clock distribution output circuit and the distributed clock input circuit includes a phase difference-voltage converting circuit for converting the phase difference between the input clock and the output clock into a voltage, and a voltage control type delay circuit for delaying the input clock corresponding to an output voltage of the phase difference-voltage converting circuit and for outputting the delayed input clock.

Clock distributing circuit

A variable level shifter has a first transconductor cell receiving a first pair of voltages, and second and third transconductor cells both receiving a second pair of voltages. The transconductor cells are differential voltage-to-current amplifiers employing field-effect transistors. The two current outputs of the first transconductor cell are coupled to respective output terminals. One current output of the second transconductor cell is coupled to one of these output terminals, and the corresponding current output of the third transconductor cell is coupled to the other output terminal. A fourth transconductor cell may be added to obtain two pairs of outputs shifted in opposite directions. A differential multiplier can be constructed using this four-cell variable level shifter and additional field-effect transistors.

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Tokyo, Japan

Satoru Tanoi