摘要:
A central processing unit sets which of the following modes a data processing device is to operate in accordance with a user program. The high-speed operation mode allows operation within a first range in which an external supply voltage is relatively high. The wide voltage range operation mode allows operation within a second range in which the external supply voltage includes the first range and a relatively low voltage range, and an upper limit of a frequency of the first clock in the wide voltage range operation mode is lower than an upper limit of a frequency of the first clock in the high-speed operation mode. The frequency of the first clock in the low power consumption operation mode is lower than the frequency of the first clock in the high-speed operation mode and the frequency of the first clock in the wide voltage range operation mode.
摘要:
Operational stability of the nonvolatile memory in plural power supply voltage modes set up in advance corresponding to the power supply voltage level is realized. A nonvolatile memory is configured with a memory array, a charge pump, a distributor for selecting an output voltage of the charge pump, and a sequencer for controlling operation of the charge pump and the distributor. The nonvolatile memory is also provided with an analyzer which notifies the sequencer of a power supply voltage mode selectively specified among plural power supply voltage modes set up in advance corresponding to power supply voltage levels, and which detects mismatch between the power supply voltage mode notified to the sequencer and an actually supplied power supply voltage and limits the operation of the charge pump and the distributor with the use of the sequencer, based on the detection result. Accordingly, operational stability of the nonvolatile memory is realized.
摘要:
A control circuit in a semiconductor memory device accessing a memory cell for a plurality of cycles includes an internal command generating circuit and a mask signal generating circuit. Upon receiving a control command, the internal command generating circuit outputs an internal signal instructing an operation to access the memory cell at H level when a mask signal is at L level, while outputs an internal signal at L level when the mask signal is at H level, because a latch circuit is reset. The mask signal generating circuit outputs the mask signal at H level for a following cycle, when the internal signal is output at H level.
摘要:
When the frequency of an external clock signal is higher than a prescribed frequency in an SDRAM, an output signal from a clock frequency detection circuit is at an L level, a transfer control signal is fixed to an H level, and first and second data buses are coupled together. Thus, a malfunction when the transfer control signal attains an H level in a pulse manner while read data is not output to the first data bus can be prevented. Accordingly, an SDRAM having a larger operating frequency range can be obtained.
摘要:
The inventive semiconductor memory device comprises a synchronous circuit formed by a PLL circuit requiring precise operations, an internal circuit group and a VDC circuit. The VDC circuit, a capacitor, a PMOS transistor for a dummy current and an NMOS transistor serving as a high impedance element are arranged for the synchronous circuit. The VDC circuit is arranged for the internal circuit group. The VDC circuit eliminates power supply noise. The PMOS transistor stabilizes the operation of a differential amplifier of the VDC circuit. The capacitor keeps potential difference between a power supply side and a GND side constant. The NMOS transistor stabilizes the voltage on the GND side.
摘要:
When a first data bus line and a second data bus line as a pair are used as a complementary bus, a complementary data signal ZDATA1 is provided to the second data bus line, and an output buffer circuit that becomes unnecessary is rendered inactive. On the other hand, when the first and second data bus lines are used as two single data buses, a differential amplifier transmits two data signals without amplification to the first and second data bus lines. A data signal DATA2 is provided to the second data bus line. The output buffer circuit is activated, and a data signal ZDATA2 is output from an output node.
摘要:
The present invention provides a semiconductor device which comprises a plurality of memory cells which stores data therein based on threshold voltages thereof, a plurality of bit lines on which read signals based on the stored data of the memory cells appear respectively, a plurality of sense amplifiers which are respectively disposed corresponding to the bit lines and which respectively detect the read signals having appeared on the bit lines and output first and second signals respectively having logical levels different from one another from first and second nodes, based on the detected read signals, and a determination unit which determines, based on the first and second signals received from the first and second nodes of the sense amplifiers, whether the threshold voltages of the memory cells are normal.
摘要:
A control circuit in a semiconductor memory device accessing a memory cell for a plurality of cycles includes an internal command generating circuit and a mask signal generating circuit. Upon receiving a control command, the internal command generating circuit outputs an internal signal instructing an operation to access the memory cell at H level when a mask signal is at L level, while outputs an internal signal at L level when the mask signal is at H level, because a latch circuit is reset. The mask signal generating circuit outputs the mask signal at H level for a following cycle, when the internal signal is output at H level.
摘要:
An internal clock signal generating circuit includes a phase comparing circuit which is made active in accordance with a control signal SEN which becomes intermittently active in a power down mode from an operation permission signal generating circuit, receives an external clock signal and an output from a delay circuit, and compares phases of the signal and the output with each other, an address generating circuit for receiving a phase comparison result and generating a delay amount control signal for controlling a delay amount, and an address decoder for receiving an output of the delay circuit and generating a decode signal for controlling the delay amount.
摘要:
The inventive semiconductor memory device comprises a synchronous circuit formed by a PLL circuit requiring precise operations, an internal circuit group and a VDC circuit. The VDC circuit, a capacitor, a PMOS transistor for a dummy current and an NMOS transistor serving as a high impedance element are arranged for the synchronous circuit. The VDC circuit is arranged for the internal circuit group. The VDC circuit eliminates power supply noise. The PMOS transistor stabilizes the operation of a differential amplifier of the VDC circuit. The capacitor keeps potential difference between a power supply side and a GND side constant. The NMOS transistor stabilizes the voltage on the GND side.