Oki Electric Industry Co., Ltd.

Mosaid Technologies Corporation

Sampei Miyamoto

Tamihiro Ishimura

Katsuaki Matsui

Hidekazu Kikuchi

Shinzo Sakuma

Cynthia Mar

Xiao Luo

Takayuki Yamamoto

Valerie L Lines

Masahumi Miyawaki

Valeria Lines

A bi-directional global data bus scheme for use in a random access memory which optimizes the performance of the data path for read and write operations while offering a uniform read and write frequency to the external processor or controller is presented. The system makes use of a dual local data bus structure which allows the column address to change on every clock cycle since the two parallel local data paths are activated on alternate clock cycles and therefore operate at half the nominal operating frequency. For the read operation, the global data buses operate differentially at the nominal operating frequency. For the write operation, the global data buses operate at half the nominal operating frequency with each global data bus of a complementary data bus pair being dedicated to either one or the other local data paths for every other clock cycle. By implementing this scheme internally, a uniform read or write operating frequency is seen by the microprocessor, thereby simplifying its interface with the memory.

Bi-directional data bus scheme with optimized read and write characters

A memory device according to the invention has a first pair of bit lines, having first and second bit lines, coupled to a first memory cell which cause a first potential difference between the first and second bit lines; a second pair of bit lines, having third and fourth bit lines, coupled to a second memory cell which causes a second potential difference between the third and fourth bit lines; a first sense amplifier having first and second transistors each of which is a first conductivity type, the gate electrode of said first transistor being connected to said first bit line, the first electrode of the first transistor being connected to the second bit line, the gate electrode of the second transistor being connected to the second bit line, the first electrode of the second transistor being connected to the first bit line; a second sense amplifier having third and fourth transistors each of which is the first conductivity type, the gate electrode of the third transistor being connected to the third bit line, the first electrode of the third transistor being connected to the fourth bit line, the gate electrode of the fourth transistor being connected to the fourth bit line, the first electrode of the fourth transistor being connected to the third bit line; and the second electrodes of said first, second, third and fourth transistors constituting a first common diffusion region formed in a first area of the major surface.

Semiconductor memory device employing an improved layout of sense

A semiconductor memory device according to the present invention comprise a plurality of arrays each supplied with a common column address signal. In an selected array, the potential of a data line is set to a potential corresponding to a potential supplied to a corresponding bit line in response to the potential of the bit line, the potential of the corresponding column address signal and the potential of a terminal. In non-selected array other than the selected array at this time, since the potential of a terminal in the non-selected array is set to a potential different from that of the terminal in the selected array, the potential of the data line remains unchanged irrespective of the column address signal.

Semiconductor memory device

A PMOS 21 and an NMOS 22, which are connected in series between a power supply potential Vcc and a ground potential Vss, perform ON and Off operation in accordance with data signals G1 and G2 from an output buffer control circuit 40, and generate an output signal. A Vpp generating circuit 50 generates a potential Vpp higher than the power supply potential Vcc and a back gate bias of the PMOS 21 is set at the potential Vpp. Even if a latch-up trigger current due to a surge voltage is produced, the back gate bias of the PMOS 21 is set at Vpp and therefore a potential difference caused in an N type well resistor becomes small and a base potential of a parasitic bipolar transistor disposed between the N type well 2 and a substrate 1 becomes approximate to the potential Vpp. Accordingly, the current which flows into the substrate 1 is suppressed and a latch-up tolerance is improved.

Semiconductor device having a CMOS element as a buffer

A booster power generating circuit according to the present invention comprises first to fourth booster circuits for supplying first to fourth booster potentials to first to fourth nodes in response to first to fourth pulse signals, a first precharge circuit for precharging the first node when controlled by the fourth booster potential from the fourth node, a second precharge circuit for precharging the third node when controlled by the second booster potential from the second node and a first output circuit for outputting the first booster potential of the first node to an output node, whereby a given booster potential can be output since there is no voltage drop of the boosted potential of the second and fourth nodes, there is obtained high potential between the first and third precharge circuits and the precharging speed of the first and third node is not slowed.

Booster power generating circuit

A semiconductor memory has a sense amplifier array shared by first and second memory cell arrays, which are selected by first and second selection signals. Interconnections between the sense amplifier array and the first memory cell array are controlled by a first transfer gate signal. When the first selection signal is inactive, the second selection signal is coupled through a first transfer gate driver to become the first transfer gate signal. When the first selection signal is active, the first transfer gate signal is decoupled from the second selection signal and driven to an elevated level.

Semiconductor memory with improved transfer gate drivers

A semiconductor memory circuit selects one memory cell group in response to an address signal having block selection information, first and second significant bit information. First, to third memory cell blocks respectively have memory cell groups each including memory cells. First, to third decoder groups respectively have first decoders each coupled to one memory cell group in the first memory cell block, second decoders each coupled to one memory cell group in the second memory cell block, and third decoders each coupled to one memory cell group in the third memory cell block. First and second logic circuits respectively output a first common block selection signal with respect to the first and second memory cell blocks in response to the block selection information of the address signal, and a second common block selection signal with respect to the second and third memory cell blocks in response to the block selection information of the address signal. Third and fourth logic circuits respectively, in response to the second and first significant information, apply first common decode signals to the first and second decoder groups upon the first common block selection signal being outputted, and a plurality of second common decode signals to the second and third decoder groups upon the second common block selection signal being outputted. In response to the first and second common decode signals, a second decoder in the second decoder group is activated to select one memory cell group in the second memory cell block.

Semiconductor memory circuit

A sense amplifier control circuit supplies a first potential to the sense amplifiers of a semiconductor memory through a set of first control transistors, each coupled in parallel to at least two and at most four sense-amplifier nodes. The first transistors are switched by a first control signal line. A second potential may be supplied to the sense amplifiers through a similar set of second control transistors, which are switched by a second control signal line. The first and second control signal lines may be driven independently, or one or both control signal lines may be driven by a set of drivers coupled in parallel between the two control signal lines.

Sense amplifier control circuit for semiconductor memory

A semiconductor memory device has plural memory cell blocks, each including memory cells storing data therein. A data bus and switching circuits transfer data from the memory cells to the data bus in response to a first logic level signal applied thereto. Column lines each have first and second ends. Each column line is connected to the corresponding switching circuit in each of the memory cell blocks. A column decoder, coupled to the first end of the column lines, provides the first logic level signal to one of the column lines upon the memory cell blocks being accessed. Potential setting circuits are coupled to the second end of the column lines, and preliminarily set the respective column lines to be in a predetermined potential so that each switching circuit is inactive prior to the column decoder providing the first logic level signal. All the memory cells in an array can be prevented from becoming inoperative even if a column line is broken.

Semiconductor memory with column line control circuits for protection

A memory device according to the invention has a first pair of bit lines, having first and second bit lines, being coupled to a first memory cell which cause a first potential difference between the first and second bit lines; a second pair of bit lines, having third and fourth bit lines, coupled to a second memory cell which causes a second potential difference between the third and fourth bit lines; a first sense amplifier having first and second transistors each of which is a first conductivity type, the gate electrode of said first transistor being connected to said first bit line, the first electrode of the first transistor being connected to the second bit line, the gate electrode of the second transistor being connected to the second bit line, the first electrode of the second transistor being connected to the first bit line; a second sense amplifier having third and fourth transistors each of which is the first conductivity type, the gate electrode of the third transistor being connected to the third bit line, the first electrode of the third transistor being connected to the fourth bit line, the gate electrode of the fourth transistor being connected to the fourth bit line, the first electrode of the fourth transistor being connected to the third bit line; and the second electrodes of said first, second, third and fourth transistors constituting a first common diffusion region formed in a first area of the major surface.

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Tokyo, Japan

Sampei Miyamoto