Mitsubishi Denki Kabushiki Kaisha

Renesas Electronics Corporation

Renesas Technology Corp.

Mitsubishi Electric Engineering Company, Limited

Susumu Tanida

Yasuhiko Tsukikawa

Masanori Hayashikoshi

Kazutoshi Hirayama

Tomio Suzuki

Kiyohiro Furutani

Takanobu Suzuki

Mikio Sakurai

Takahiko Fukiage

Takeshi Hamamoto

Shinji Tanaka

Seiji Sawada

Takayuki Miyamoto

Hiroshi Akamatsu

Yasuhiro Matsumoto

Masaya Nakano

Goro Hayakawa

Yukinobu Adachi

Hisao Kobashi

Tooru Ichimura

Osamu Kuromiya

There is provided a charge pump circuit which can prevent EMI noise of a frequency component independent of an operation clock frequency from occurring at the time of a change from a disable state to an enable state. The charge pump circuit includes a detection signal synchronization circuit which outputs a synchronization detection signal generated by synchronizing a detection signal outputted from a level detection circuit to a clock signal outputted from an oscillator circuit. The synchronization detection signal is used as a pump enable signal, and a first pump capacitance and a second pump capacitance in a pump circuit body are charged and discharged in response to the synchronization detection signal and the clock signal outputted from the oscillator circuit.

Charge pump circuit

A bare chip is provided with a pad for activation/deactivation control to which a deactivation control signal for converting a bare chip that has been detected as being defective into the deactivated condition is inputted. When a deactivation control signal is inputted to the pad for activation/deactivation control, internal circuit prevent a signal that has been inputted from the pad for data input/output control from being inputted to an internal circuit located further inside than the input buffer circuit. Thereby, the bare chip that has been detected as being defective can be converted to the deactivated condition. As a result, a semiconductor memory module can be obtained that can be repaired by newly mounting a good function chip without allowing the bare chip that has been detected as being defective to interfere with the functions of the semiconductor memory module.

Semiconductor memory module

The internal power-supply potential generating circuit includes a reference potential generating circuit having small dependency on an external power-supply potential and on a temperature, an MOS transistor for pull up, a level shifter producing a potential lower than a reference potential by a prescribed voltage to a first node and producing a potential lower than an internal power-supply potential by a voltage of the sum of the prescribed potential and an offset potential to a second node, and a differential amplifier bringing an MOS transistor out of conduction in response to the potential of the second node reaching the potential of the first node. Thus, the reference potential may be set lower by the offset voltage, allowing stable reference potential and internal power-supply potential to be obtained even if the external power-supply potential is lowered.

Internal power-supply potential generating circuit

A test mode reference potential generating circuit outputs a reference potential from an output node by activation of a test mode signal. When a sample signal is in an activated state, a transfer gate is turned on, and a capacitor stores the reference potential. When the test is being conducted, the transfer gate is turned off by inactivation of the sample signal, and thus the reference potential stored in the capacitor is output from a node. Thus, the semiconductor memory device according to the present invention can generate a stable reference potential during the test mode.

Semiconductor memory device having reference potential generating circuit

A potential of an I/O line pair is defined at Vcc2&minus;Vth by a clamp circuit, and a clamp voltage is generated by a current mirror circuit including an n channel MOS transistor and p channel MOS transistors and a constant current source. The I/O line pair is thus clamped through p channel MOS transistors connected in series between the I/O line pair.

Semiconductor memory device provided with I/O clamp circuit

The present invention provides a semiconductor memory device which can detect without fail an abnormal operating current caused by a defect of a transistor comprising a sense amplifier circuit provided for each operating block in a short period of time, where in a test mode, carried out to see whether or not the operating current of the semiconductor memory device,satisfies the standard, the switching circuit,is provided for activating sense amplifier circuits,to,in all the operating blocks,to,irrelevant of the block selecting signals BS,to BS,inputted from the outside at the time of test mode.

Semiconductor memory device employing an abnormal current consumption detection scheme

A semiconductor memory device includes a control circuit, a test mode control circuit, an internal period setting circuit and an address latch circuit. The control circuit detects whether test mode is designated or not. The test mode control circuit detects whether or not self disturb test mode is designated. The internal period setting circuit repeatedly generates a clock signal of a prescribed period when the test mode and the self disturb test mode are designated. Simultaneously, the address latch circuit latches an address at a fall of a row address strobe signal. The row decoder is activated in response to the clock signal, and repeatedly sets the word line corresponding to the latched address to the selected state.

Semiconductor memory device having selection circuit for arbitrarily

A clock buffer in a semiconductor memory device includes two kinds of interface circuits, i.e., an LVTTL interface and an SSTL interface. When the semiconductor memory device is set to a specific mode (self-refresh mode) for suppressing a power consumption, the LVTTL is used for taking in an external signal. In a mode other than the self-refresh mode, the SSTL interface is used to take in an externally supplied signal. Thereby, a current can be suppressed in the specific mode.

Semiconductor memory device provided with an interface circuit consuming

A contact check circuit of a semiconductor device includes N-channel MOS transistors connected in series between pads located at opposing ends, with their gates respectively connected to intermediate pads. At the contact check, conduction between opposing pads is checked, applying an 'H' level to probes corresponding to the pads. Thus contact between the pads and probes of a semiconductor testing apparatus can be checked at once.

Semiconductor device having contact check circuit

A reset signal generating circuit in a synchronous semiconductor memory device outputs a reset signal ZPOR1 in response to a power on reset signal ZPOR generated immediately after power on and an initialize command (for example, a precharge command) executed for initialization after power on. A test mode register included in a mode setting circuit receives as a reset signal, the reset signal ZPOR1. Consequently, a test mode signal output attains to an NOP state, or output of the test mode signal is stopped.

Synchronous semiconductor device having circuitry capable of surely

In an address transition detecting circuit, signal conversion detecting circuits output complementary time difference signals which are inverted in response to potential level changes of corresponding address lines respectively. Waveform shaping one-shot pulse generating circuits receive corresponding complementary time difference signals and output one-shot pulse signals of prescribed time widths. A waveform composing circuit outputs an ATD signal of a prescribed pulse length in response to activation of any one-shot pulse signal. Therefore, the lengths of the one-shot pulses outputted from the waveform shaping one-shot pulse generating circuits remain unchanged even if the potential level of any signal line is abruptly converted, and an ATD signal of a constant pulse length is regularly outputted.

Semiconductor memory device comprising address transition detecting

A semiconductor memory device includes four memory cell arrays, four output pads formed in a linear manner at the center of a semiconductor substrate, four output control circuits for generating readout data signals and control signals, four signal generation circuits responsive to the readout data signals for generating complementary pairs of data signals, and responsive to the control signals, four signal line groups including four signal lines connected between the output control circuits and the signal generation circuits, four output drivers responsive to pairs of data signals for supplying data to the output pads, and four signal line pairs connected between the signal generation circuits and output drivers. Signal generation circuits of great size are arranged at the center of the semiconductor substrate where the layout margin is great, and only the output driver is arranged in the proximity of the output pad where the layout margin is small. Therefore, the chip area is reduced. Access is speeded since the signal lines forming the signal line group are shorter in length, though greater in number, than the signal lines forming the signal line pair.

Semiconductor memory device having layout area of periphery of output

When a disturb refresh mode is detected by a mode detecting circuit, a row decoder control circuit simultaneously activates every several word lines of a memory cell array of a block selected by an operation block selecting circuit through a row decoder and a driving circuit, reads out data written in a normal mode, and determines a memory cell having a threshold value lower than that of a design value upon determination of match of read data and written data.

Semiconductor memory device

An external power source voltage Vcc rises until it exceeds the threshold voltage Vth of an NMOS transistor diode-connected between the external power source (voltage Vcc) and an internal boosted power source (voltage Vpp), whereupon the NMOS transistor is turned on, supplying the internal boosted power source with a voltage (Vcc-Vth) until the power source voltage Vcc reaches its final value. And when the internal reset signal ZPOR expires, the internal boosted power source generating circuit is started to operate so that the internal boost source voltage Vpp is boosted to an intended level Vpp. As a result, when the power is turned on, early stabilization of the boosted power source voltage is realized in a semiconductor storage device.

Growing community of inventors

Hyogo, Japan

Susumu Tanida