Abstract: A manner of generating internal voltages such as a high voltage, an intermediate voltage and an internal power supply voltage is switched in accordance with a power supply level setting signal. When the voltage level of an external power supply voltage is low, a current drive transistor receiving an output of a comparing circuit and an auxiliary drive transistor are forcedly set in a conductive state, and external power supply voltage is transmitted on an internal power supply line. At this time, the comparing operation of the comparing circuit is stopped. When the level of the external power supply voltage is high, the comparing circuit is activated down convert the external power supply voltage for generating a peripheral power supply voltage on the internal power supply line.

Abstract: Data pad regions are arranged in four divided regions of a semiconductor memory chip of a rectangular shape, respectively, and data pads are selectively utilized in each of the four divided regions in accordance with a word structure. Thus, it is possible to implement a semiconductor memory chip capable of being assembled in both a single chip package and a multi chip package.

Abstract: The semiconductor memory device includes a refresh timer for determining a refresh cycle of self-refresh operation. The refresh timer includes a voltage regulator, a ring oscillator and a counter. The voltage regulator generates a bias voltage having positive temperature characteristics. The ring oscillator varies an oscillation cycle of a pulse signal according to the bias voltage. The counter counts a prescribed number of pulse signals and generates a refresh signal for executing refresh operation. The semiconductor memory device thus varies the refresh cycle according to a temperature change, and executes refresh operation with an appropriate refresh cycle.

Abstract: A row address decoder of a semiconductor memory device generates internal row address signals RAD<0:11> and /RAD<0:11> by switching most significant bit and least significant bit of row address signals RA<0:11> and /RA<0:11> that correspond to address signals A0 to A11, respectively. In a twin cell mode, the least significant bits RAD<0> and /RAD<0> of the internal row address signals corresponding to the most significant bits RA<11> and /RA<11> of the row address signal that are not used are selected simultaneously by row address decoder, and two adjacent word lines are activated simultaneously. Consequently, the configuration of memory cell in the semiconductor memory device can electrically be switched from the normal single memory cell type to the twin memory cell type.

Abstract: Power to operates memory bank of DRAM stably is supplied with reduced power consumption. A semiconductor storage unit includes multiple arrays forming memory banks on a substrate, first and second power supplies. Multiple arrays are arranged like a matrix and surround the central region of the substrate. Each memory bank consists of two of the multiple arrays. Each first power supply supplies driving power to a peripheral circuit which drives each multiple array. Second power supplies are arranged at four corners of the central region, each supply provides access power to word lines which access the multiple arrays. The first power supplies are mounted to a central and the opposite side for predetermined arrays, serve as a main and an auxiliary power supply to provide main and auxiliary power (smaller than the main power), and provide distantly arranged two of the multiple arrays forming a memory bank with power.

Abstract: A clock buffer of a DRAM includes: a first NAND gate which is driven by a first internal power supply voltage (2.5 V) and which determines the level of an input clock signal if the DRAM is used for a TTL-system interface (MLV=2.5 V); and a second NAND gate which is driven by a second internal power supply voltage (1.8 V) and which determines the level of the input clock signal if the DRAM is used for a 1.8 V-system interface (MLV=0 V). Accordingly, in each of the first and second NAND gates, sizes of four MOS transistors can be set at optimum values, respectively.

Abstract: A semiconductor memory device includes banks, predecoders, a latch circuit, a counter, a fuse and buffers. The bank includes a plurality of memory cells arranged in rows and columns, and others. The predecoders are disposed in a central portion of the semiconductor memory device. The predecoder produces a predecode signal for selecting each of the banks based on a bank address received from the buffer, and outputs the predecode signal to the banks. The predecoder produces the predecode signal for selecting each of the banks based on the bank address, and outputs the predecode signal to the banks. Consequently, interconnections in the central portion can be reduced in number.

Abstract: The semiconductor memory device includes a refresh timer for determining a refresh cycle of self-refresh operation. The refresh timer includes a voltage regulator, a ring oscillator and a counter. The voltage regulator generates a bias voltage having positive temperature characteristics. The ring oscillator varies an oscillation cycle of a pulse signal according to the bias voltage. The counter counts a prescribed number of pulse signals and generates a refresh signal for executing refresh operation. The semiconductor memory device thus varies the refresh cycle according to a temperature change, and executes refresh operation with an appropriate refresh cycle.

Abstract: Data pad regions are arranged in four divided regions of a semiconductor memory chip of a rectangular shape, respectively, and data pads are selectively utilized in each of the four divided regions in accordance with a word structure. Thus, it is possible to implement a semiconductor memory chip capable of being assembled in both a single chip package and a multi chip package.

Abstract: A manner of generating internal voltages such as a high voltage, an intermediate voltage and an internal power supply voltage is switched in accordance with a power supply level setting signal. When the voltage level of an external power supply voltage is low, a current drive transistor receiving an output of a comparing circuit and an auxiliary drive transistor are forcedly set in a conductive state, and external power supply voltage is transmitted on an internal power supply line. At this time, the comparing operation of the comparing circuit is stopped. When the level of the external power supply voltage is high, the comparing circuit is activated down convert the external power supply voltage for generating a peripheral power supply voltage on the internal power supply line.

Abstract: A clock buffer of a DRAM includes: a first NAND gate which is driven by a first internal power supply voltage (2.5 V) and which determines the level of an input clock signal if the DRAM is used for a TTL-system interface (MLV=2.5 V); and a second NAND gate which is driven by a second internal power supply voltage (1.8 V) and which determines the level of the input clock signal if the DRAM is used for a 1.8 V-system interface (MLV=0 V). Accordingly, in each of the first and second NAND gates, sizes of four MOS transistors can be set at optimum values, respectively.

Abstract: A row address decoder of a semiconductor memory device generates internal row address signals RAD<0:11>and /RAD<0:11>by switching most significant bit and least significant bit of row address signals RA<0:11>and /RA<0:11>that correspond to address signals A0 to A11, respectively. In a twin cell mode, the least significant bits RAD<0>and /RAD<0>of the internal row address signals corresponding to the most significant bits RA<11>and /RA<11>of the row address signal that are not used are selected simultaneously by row address decoder, and two adjacent wold lines are activated simultaneously. Consequently, the configuration of memory cell in the semiconductor memory device can electrically be switched from the normal single memory cell type to the twin memory cell type.

Abstract: Pad lines are placed on the peripheral region of a chip along EAST band and WEST band (E/W band). In order to allow the chip with pads arranged on the peripheral region to be adaptable to a TSOP, VDD and VSS pads are arranged on the edge region on NORTH band and SOUTH band (N/S band) near the center of the N/S band. Moreover, in consideration of frame design for the TSOP, some pads on the ends of the pad lines among the pads included in the pad lines are arranged in reverse order relative to the order of pins. Further, VDDQ and VSSQ pads are arranged in the same order as that of pins for a package which requires no consideration of frame design. On the other hand, for use in a BGA package, VDD and VSS pads are arranged in pairs at respective ends of the pad lines. A semiconductor memory device with this pad arrangement is accordingly adaptable to various types of packages.

Abstract: Pad lines are placed on the peripheral region of a chip along EAST band and WEST band (E/W band). In order to allow the chip with pads arranged on the peripheral region to be adaptable to a TSOP, VDD and VSS pads are arranged on the edge region on NORTH band and SOUTH band (N/S band) near the center of the N/S band. Moreover, in consideration of frame design for the TSOP, some pads on the ends of the pad lines among the pads included in the pad lines are arranged in reverse order relative to the order of pins. Further, VDDQ and VSSQ pads are arranged in the same order as that of pins for a package which requires no consideration of frame design. On the other hand, for use in a BGA package, VDD and VSS pads are arranged in pairs at respective ends of the pad lines. A semiconductor memory device with this pad arrangement is accordingly adaptable to various types of packages.

Abstract: A semiconductor memory device includes banks, predecoders, a latch circuit, a counter, a fuse and buffers. The bank includes a plurality of memory cells arranged in rows and columns, and others. The predecoders are disposed in a central portion of the semiconductor memory device. The predecoder produces a predecode signal for selecting each of the banks based on a bank address received from the buffer, and outputs the predecode signal to the banks. The predecoder produces the predecode signal for selecting each of the banks based on the bank address, and outputs the predecode signal to the banks. Consequently, interconnections in the central portion can be reduced in number.

Abstract: The output circuit has an output transistor adjusted in driving capability, using a negative voltage or changing a transistor size in accordance with the level of output power supply voltage. Particularly, by increasing the driving capability of a P-channel MOS transistor for pulling up the output node, an output signal can be generated at high speed while suppressing reduction of the driving capability of the P-channel MOS transistor even under a low output power supply voltage condition. An output circuit that can drive an output node with an optimum driving capability even if an output power supply voltage is changed, is provided.

Abstract: Power to operates memory bank of DRAM stably is supplied with reduced power consumption. A semiconductor storage unit includes multiple arrays forming memory banks on a substrate, first and second power supplies. Multiple arrays are arranged like a matrix and surround the central region of the substrate. Each memory bank consists of two of the multiple arrays. Each first power supply supplies driving power to a peripheral circuit which drives each multiple array. Second power supplies are arranged at four corners of the central region, each supply provides access power to word lines which access the multiple arrays. The first power supplies are mounted to a central and the opposite side for predetermined arrays, serve as a main and an auxiliary power supply to provide main and auxiliary power (smaller than the main power), and provide distantly arranged two of the multiple arrays forming a memory bank with power.