摘要:
A semiconductor memory device, which refreshes memory cells to retain data, has a first refresh mode and a second refresh mode. The first refresh mode is a mode for refreshing all of the memory cells, and the second refresh mode is a mode for refreshing a part of the memory cells. By refreshing only designated areas where data must be retained, power consumption in a refresh operation can be reduced, drastically cutting power consumption in a power-down mode.
摘要:
A semiconductor memory device includes memory cells, word lines connected to the memory cells, bit lines connected to the memory cells, and a first circuit which resets the bit lines to a reset potential which is based on data read in a previous read cycle.
摘要:
A system and a semiconductor device for realizing such a system are disclosed. The system uses at least a semiconductor device for retrieving an input signal in synchronism with an internal clock generated from an external clock, the input signal remaining effectively in synchronism with the external clock. Even in the case where a phase difference develops between a clock and a signal at the receiving end, or even in the case where a phase difference develops between a clock input circuit and other signal input circuits in the semiconductor device at the receiving end, data can be transferred at high speed. Each input circuit of the semiconductor device at the receiving end includes an input timing adjusting circuit for adjusting the phase of the clock applied to the input circuit in such a manner that the input circuit retrieves the input signal in an effective and stable state. In the case where the skew between the input signals is small as compared with the skew between the input signals and the clock, an input timing adjusting circuit is shared by a plurality of the input circuits.
摘要:
A system and a semiconductor device for realizing such a system are disclosed. The system uses at least a semiconductor device for retrieving an input signal in synchronism with an internal clock generated from an external clock, the input signal remaining effectively in synchronism with the external clock. Even in the case where a phase difference develops between a clock and a signal at the receiving end, or even in the case where a phase difference develops between a clock input circuit and other signal input circuits in the semiconductor device at the receiving end, data can be transferred at high speed. Each input circuit of the semiconductor device at the receiving end includes an input timing adjusting circuit for adjusting the phase of the clock applied to the input circuit in such a manner that the input circuit retrieves the input signal in an effective and stable state. In the case where the skew between the input signals is small as compared with the skew between the input signals and the clock, an input timing adjusting circuit is shared by a plurality of the input circuits.
摘要:
A DRAM (Dynamic Random Access Memory) having a plurality of memory cells includes a data read/write circuit reading or writing data for the memory cells, a self-refresh circuit refreshing data stored in the memory cells, and a power supply unit for supplying electric power to the data read/write circuit and the self-refresh circuit, the electric power having a first voltage level in a normal operation mode and a second voltage level in a self-refresh mode, wherein the second voltage level is lower than the first voltage level.
摘要:
A semiconductor integrated circuit includes a switch unit for controlling the supply of a power source voltage to a signal amplification circuit for receiving an input signal, and a control unit for selectively turning ON and OFF the switch unit in accordance with the amplitude or frequency of this input signal. By the constitution, it is possible to provide an input circuit or an output circuit capable of being applied to an input/output interface adapted for a small amplitude operation.
摘要:
A method of making an SDRAM (synchronous dynamic random access memory) into either a low-speed type or a high-speed type includes the steps of determining an electrical connection of a predetermined electrode of the SDRAM, and providing the predetermined electrode with a voltage level defined by the electrical connection, the voltage level determining whether the SDRAM is made into the low-speed type or the high speed type, wherein the low-speed type can carry out consecutive writing operations at a low clock rate for two addresses having the same row address, and the high-speed type can carry out simultaneous writing operations at a high clock rate for two addresses having the same row address and consecutive column addresses.
摘要:
A semiconductor memory device has a plurality of main memory blocks formed on a chip and each having a redundancy, a sub-memory block formed on the chip and having a substantially identical construction as that of each main memory block, a defect address memory circuit for storing address data of the main memory block that cannot be saved by the redundancy, and a redundancy control circuit for selecting the sub-memory block when a defective main memory block is selected.
摘要:
A static semiconductor memory device includes a memory cell array including a large number of static memory cells arranged in a matrix fashion, a word decoder, a column decoder, and a data buffer. An address delay buffer is provided for delaying an input address signal by a predetermined delay time and a comparator circuit is provided for comparing the input address signal with the delayed address signal from the address delay buffer, so that even if the input address signal is disturbed by noise, the erroneous data corresponding to the disturbed address signal is not read into the data buffer by means of the output signal of the comparator circuit and is not output from the memory device.
摘要:
A semiconductor memory device includes, a plurality of word lines, a plurality of bit lines and a plurality of memory cells each connected between the word lines and the bit lines at each intersection of the word lines and bit lines. A plurality of sense amplifiers, each connected to each pair of bit lines, are for amplifying a difference in potential between each of the bit lines; a plurality of bit line reset circuits, each connected to each pair of the bit lines, the difference in potential being held during the read/write cycles. A transfer mode setting circuit is for optionally selecting a first word line and thereafter selecting a second word line, and for simultaneously reading out data in each memory cell connected to the first word line onto each bit line and thereafter simultaneously writing data on each bit line amplified by the sense amplifier into each corresponding memory cell connected to the second word line.