A clock mode configuration circuit for a memory device is described. A memory system includes any number of memory devices serially connected to each other, where each memory device receives a clock signal. The clock signal can be provided either in parallel to all the memory devices or serially from memory device to memory device through a common clock input. The clock mode configuration circuit in each memory device is set to a parallel mode for receiving the parallel clock signal, and to a serial mode for receiving a source synchronous clock signal from a prior memory device. Depending on the set operating mode, the data input circuits will be configured for the corresponding data signal format, and the corresponding clock input circuits will be either enabled or disabled. The parallel mode and the serial mode is set by sensing a voltage level of a reference voltage provided to each memory device.

An IC memory controller includes a first controller command/address (C/A) interface to transmit first and second read commands for first and second read data to a first memory C/A interface of a first bank group of memory. A second command/address (C/A) interface transmits third and fourth read commands for third and fourth read data to a second memory C/A interface of a second bank group of memory. For a first operating mode, the first and second read data are received after respective first delays following transmission of the first and second read commands and at a first serialization ratio. For a second operating mode, the first and second read data are received after respective second and third delays following transmission of the first and second read commands. The second and third delays are different from the first delays and from each other. The first and second data are received at a second serialization ratio that is different than the first serialization ratio.

A duty adjustment circuit, and a delay locked loop circuit and a semiconductor memory device including the same are provided. The duty adjustment circuit includes a pulse generator configured to generate a pulse signal at a constant pulse width regardless of a frequency of a reference clock signal, based on frequency information, a code generator configured to generate a first predetermined number of delayed pulse signals by delaying the pulse signal, as a first code in response to the pulse signal, and a duty adjuster configured to receive a delay clock signal, and generate a duty correction clock signal by adjusting a slope of rising transition and a slope of falling transition of the delay clock signal in response to the first code and a second code.

A memory system includes a memory controller and a memory module, where the memory controller is arranged for generating at least a first clock signal and an inverted first clock signal, and the memory module is arranged to receive at least the first clock signal and the inverted first clock signal from the memory controller. In addition, the memory module includes a termination module, and the first clock signal is coupled to the inverted first clock signal through the termination module.

A memory system includes a memory controller and a memory module. The memory controller is arranged for selectively generating at least a clock signal and an inverted clock signal. The memory module includes a first termination resistor, a second termination resistor and a switch module, where a first node of the first termination resistor is to receive the clock signal, a second termination resistor, wherein a first node of the second termination resistor is to receive the inverted clock signal, and the switch module is arranged for selectively connecting or disconnecting a second node of the second termination resistor to a second node of the first termination resistor.

The present technology includes a memory system and a method of operating the memory system. The memory system includes a memory device including an interface circuit, the interface circuit storing first system data, and a semiconductor memory; and a controller configured to output a read enable signal and a first read command for the first system data to the memory device. The semiconductor memory transfers a data strobe signal to the interface circuit in response to the read enable signal, the interface circuit reads the first system data in response to the first read command and transmits the read first system data to the controller in synchronization with the data strobe signal.

Apparatuses and methods for setting a duty cycler adjuster for improving clock duty cycle are disclosed. The duty cycle adjuster may be adjusted by different amounts, at least one smaller than another. Determining when to use the smaller adjustment may be based on duty cycle results. A duty cycle monitor may have an offset. A duty cycle code for the duty cycle adjuster may be set to an intermediate value of a duty cycle monitor offset. The duty cycle monitor offset may be determined by identifying duty cycle codes for an upper and for a lower boundary of the duty cycle monitor offset.

A memory interface circuit includes a plurality of receivers and a signal detector. The plurality of receivers are arranged for receiving at least a clock signal and a plurality of command signals from a memory controller, respectively. The signal detector is arranged for detecting whether the memory interface circuit receives the clock signal or not to generate a detection result to enable or disable the plurality of receivers.

A semiconductor device may be provided. The semiconductor device may be configured to adjust a level of a first strobe signal to a predetermined level during a first time period. The semiconductor device may be configured to adjust a swing width of the first strobe signal during a second time period.

The disclosed embodiments relate to components of a memory system that support timing-drift calibration. In specific embodiments, this memory system contains a memory device (or multiple devices) which includes a clock distribution circuit and an oscillator circuit which can generate a frequency, wherein a change in the frequency is indicative of a timing drift of the clock distribution circuit. The memory device also includes a measurement circuit which is configured to measure the frequency of the oscillator circuit.