Abstract: A memory module includes a plurality of memory chips and a plurality of data register buffers mounted on the module substrate. At least two memory chips are allocated to each of the data register buffers. Each of the data register buffers includes M input/output terminals (M is a positive integer equal to or larger than 1) that are connected to the data connectors via a first data line and N input/output terminals (N is a positive integer equal to or larger than 2M) that are connected to corresponding memory chips via second and third data lines, so that the number of the second and third data lines is N/M times the number of the first data lines. According to the present invention, because the load capacities of the second and third data lines are reduced by a considerable amount, it is possible to realize a considerably high data transfer rate.

Abstract: A memory module includes a plurality of memory chips, a plurality of data register buffers, and a command/address/control register buffer mounted on a module PCB. The data register buffers perform data transfers with the memory chips. The command/address/control register buffer performs buffering of a command/address/control signal and generates a control signal. The buffered command/address/control signal is supplied to the memory chips, and the control signal is supplied to the data register buffers. According to the present invention, because line lengths between the data register buffers and the memory chips are shortened, it is possible to realize a considerably high data transfer rate.

Abstract: A semiconductor device includes a fuse element, a read-out circuit that reads out a memory content of the fuse element in response to a first internal reset signal that is activated in response to transition of an external reset signal, and a latch circuit that holds therein the memory content read out by the read-out circuit and is reset by a second internal reset signal that is activated based on an activation period of the external reset signal. With this configuration, even when the activation period of the external reset signal is long, the time for which a current flows through the fuse element can be shortened, thereby making it possible to reduce a current consumption at the time of a reset operation.

Abstract: To provide a semiconductor device including a pair of antifuse elements at either a high level or a low level, an OR circuit that outputs different logic information for a case that at least one of the antifuse elements is at a high level and a case that both of the antifuse elements are at a low level, and an exclusive OR circuit that outputs different logic information for a case that the logic states are different from each other and a case that they are same as each other.

Abstract: To include a power-down control circuit that suspends an operation of a predetermined internal circuit in response to a power-down command, and an external terminal to which a selection signal is input from outside simultaneously with issuance of a power-down command. The power-down control circuit suspends an operation of a DLL circuit when the selection signal is at a low level, and continues an operation of the DLL circuit when the selection signal is at a high level. According to the present invention, by using the selection signal input simultaneously with a power-down command, mode selection can be made on-the-fly.

Abstract: A latency counter includes: a frequency-dividing circuit that generates a plurality of divided clocks LCLKE and LCLKO of which the phases differ each other based on an internal clock LCLK; and frequency-divided counter circuits each of which counts a latency of an internal command based on the corresponding divided clocks LCLKE and LCLKO. Thus, the counting of the latency is performed based not on the internal clock LCLK itself but on the divided clocks LCLKE and LCLKO obtained by frequency-dividing the internal clock LCLK. Thus, even when a frequency of the internal clock LCLK is high, an operation margin can be sufficiently secured.

Abstract: To decrease the circuit scale necessary for the calibration of the output circuit and to decrease the time required for the calibration operation. The invention includes a first output buffer and a second output buffer that are connected to a data pin, and a calibration circuit that is connected to a calibration pin. The first output buffer and the second output buffer include plural unit buffers. The unit buffers have mutually the same circuit structures. With this arrangement, the impedances of the first output buffer and the second output buffer can be set in common, based on the calibration operation using the calibration circuit. Consequently, both the circuit scale necessary for the calibration operation and the time required for the calibration operation can be decreased.

Abstract: A semiconductor device includes a fuse element, a read-out circuit that reads out a memory content of the fuse element in response to a first internal reset signal that is activated in response to transition of an external reset signal, and a latch circuit that holds therein the memory content read out by the read-out circuit and is reset by a second internal reset signal that is activated based on an activation period of the external reset signal. With this configuration, even when the activation period of the external reset signal is long, the time for which a current flows through the fuse element can be shortened, thereby making it possible to reduce a current consumption at the time of a reset operation.

Abstract: To provide a semiconductor device including a skew detecting circuit activated in a write leveling mode, and an ODT control circuit that activates a terminating resistance circuit connected to a data strobe terminal by using an ODT signal. The ODT control circuit includes counters that delay the ODT signal, activates the terminating resistance circuit by using the ODT signal having passed the counters in a normal operation mode, and activates the terminating resistance circuit by using the ODT signal having bypassed the counters in the write leveling mode. With this configuration, in the write leveling mode, a write leveling operation can be performed quickly without waiting for latency of the ODT signal.

Abstract: To provide a semiconductor device including a skew detecting circuit activated in a write leveling mode, and an ODT control circuit that activates a terminating resistance circuit connected to a data strobe terminal by using an ODT signal. The ODT control circuit selects a first resistance mode when a dynamic ODT is in an unused state in the write leveling mode, and selects a second resistance mode when the dynamic ODT is in a used state in the write leveling mode. With this configuration, a resistance in a used state of the dynamic ODT and that in an unused state of the dynamic ODT can be reproduced in an actual write operation. Consequently, a more accurate write leveling operation can be performed.

Abstract: To include two counter circuits that change impedances of two replica circuits, respectively, and an impedance adjustment control circuit that controls the counter circuits to update count values of the counter circuits. The impedance adjustment control circuit controls one of the counter circuits to finish updating the count value of the counter circuit in response to a change of the impedance of the corresponding replica circuit from a state of being lower than an impedance of an external resistor to a state of being higher than the impedance of the external resistor, and controls the other counter circuit to finish updating the count value of the other counter circuit in response to a change of the impedance of the other replica circuit from a state of being higher than the impedance of the former replica circuit to a state of being lower than the impedance of the former replica circuit. With this configuration, the adjust errors generated in the replica circuits are canceled.

Abstract: A semiconductor device includes first, second and third terminals respectively receiving first, second and third input signals from outside, first, second and third input buffers respectively coupled to the first, second and third terminals, the first, second and third input buffers producing first, second and third buffered signals responsive to the first, second and third input signals, respectively, and first and second gate circuits respectively coupled to the first and second input buffers, the first and second gate circuits coupled to the third input buffer in common, the first and second gate circuits respectively driving output nodes thereof in response to the first and second buffered signals when the third buffered signal is activated, and each of the first and second gate circuits holding the output nodes thereof at a fixed level irrelatively to the first and second buffered signals when the third buffered signal is inactivated.

Abstract: A semiconductor device includes a latency setting circuit setting the latency, an input command circuit outputting a normal-phase (reverse-phase) command signal obtained by capturing an input command signal using a normal-phase (reverse-phase) clock, first and second counter circuits each including latch circuits sequentially shifting the normal-phase (reverse-phase) command signal based on the normal-phase (reverse-phase) clock, a selector circuit controlling a signal path so that the normal-phase (reverse-phase) command signal is transmitted through the first (second) counter circuit when an even latency is set and the normal-phase (reverse-phase) command signal is transmitted so as to be shifted from the first (second) counter circuit to the second (first) counter circuit when an odd latency is set, and a control circuit controlling so that the latch circuits of the first (second) counter circuit are activated in response to the input command signal and stopped after an operation period is elapsed.

Abstract: A semiconductor memory device includes an FIFO block connected to a data input/output terminal DQ, a time-division transfer circuit that inputs and outputs in parallel n-bit data inputted and outputted continuously via the data input/output terminal DQ, a data bus RWBS that performs a data transfer between the time-division transfer circuit and the FIFO block, and a mode register that sets a burst length. When a minimum burst length settable to the mode register is m (<n), the time-division transfer circuit performs the data transfer using the data bus in units of m bits irrespective of the burst length. Thereby, it becomes possible to set the burst length smaller than a prefetch number without performing a burst chop.

Abstract: A reference voltage generating circuit includes a current generating section, a voltage generating section, a voltage dividing circuit, and a synthesis section. The current generating section generates a first current having a positive temperature coefficient. The voltage generating section generates a voltage having a negative temperature coefficient. The voltage dividing circuit divides the voltage of the negative temperature coefficient, generated by the voltage generating section. The synthesis section generates a voltage which is the sum of a terminal voltage obtained on causing the first current through a resistor and a voltage obtained on dividing the voltage having the negative temperature coefficient by the voltage dividing circuit, and outputs the sum voltage generated as a reference voltage.

Abstract: A semiconductor storage device is provided which enables use of an overdrive method at low voltage and for a small device area. The semiconductor device includes: memory cells; sense amplifiers, each having P-channel and N-channel MOS transistors and amplifying a signal read from a memory cell; a first power supply line connected to a source terminal of the P-channel MOS transistor provided in each of the sense amplifiers; a second power supply line which supplies an overdrive voltage to the sense amplifiers at a potential higher than a write potential of the memory cell; a third power supply line connected to an external power supply, a connection element which connects and disconnects the first power supply line and the second power supply line; a capacitance element connected to the second power supply line; and a resistance element inserted between the second power supply line and the third power supply line.

Abstract: An address counter includes FIFO units and first to third command counters that controls the groups. In the FIFO units, latch circuits including input gates and output gates are connected in parallel. The first command counter conducts any one of the input gates in response to a first internal command; the second command counter conducts any one of the output gates in response to a second internal command; and the third command counter conducts any one of the output gates in response to a third internal command. Thereby, the same address signals can be outputted successively at a plurality of timings, and thus, a circuit scale of the address counter can be reduced.

Abstract: A synchronous semiconductor device includes: input buffers; a latch-signal generating circuit that generates a latch signal based on a clock signal; latch circuits that latch an address signal in response to the latch signal; delay circuits that supply the latch circuits with the address signal in synchronism with the latch signal; NOR gate circuits that inactivate the address signal in response to a chip select signal becoming inactive, the NOR gate circuits being arranged between the input buffers and the delay circuits. According to the present invention, without stopping an operation of the input buffers or an internal clock signal, consumed power generated between the input buffers and the latch circuits can be effectively reduced.

Abstract: A semiconductor device includes a latency setting circuit setting the latency, an input command circuit outputting a normal-phase (reverse-phase) command signal obtained by capturing an input command signal using a normal-phase (reverse-phase) clock, first and second counter circuits each including latch circuits for sequentially shifting the normal-phase (reverse-phase) command signal based on the normal-phase (reverse-phase) clock, a selector circuit controlling a signal path so that the normal-phase (reverse-phase) command signal is transmitted through the first (second) counter circuit when an even latency is set and the normal-phase (reverse-phase) command signal is transmitted so as to be shifted from the first (second) counter circuit to the second (first) counter circuit when an odd latency is set, and a control circuit controlling so that the latch circuits of the first (second) counter circuit are activated in response to the input command signal and stopped after an operation period is elapsed.

Abstract: A DLL circuit includes a delay line (CDL) (10) that delays a clock signal at a relatively coarse adjustment pitch, a delay line (FDL) (20) that delays the clock signal at a relatively fine adjustment pitch, and phase detecting circuits and counter control circuits that control delay amounts of the delay lines (10, 20). The counter control circuits control the delay line (10) by a linear search method, and control the delay line (20) by a binary search method. As a result, even when the number of bits of the count signal for adjusting the delay line (20) is increased, a delay amount can be determined at a high speed.