摘要:
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.
摘要:
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.
摘要:
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.
摘要:
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.
摘要:
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.
摘要:
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.
摘要:
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.
摘要:
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.
摘要:
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.
摘要:
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.