Abstract: A memory device includes a memory cell array that includes a plurality of memory cell rows; and a refresh address generator configured to store flags respectively corresponding to the plurality of memory cell rows, generate refresh row addresses respectively corresponding to the plurality of memory cell rows by performing a count operation, and according to the flags, change a refresh period of the plurality of memory cell rows.

Abstract: A memory device includes a memory cell array that includes a plurality of memory cell rows; and a refresh address generator configured to store flags respectively corresponding to the plurality of memory cell rows, generate refresh row addresses respectively corresponding to the plurality of memory cell rows by performing a count operation, and according to the flags, change a refresh period of the plurality of memory cell rows.

Abstract: A memory device includes a memory cell array that includes a plurality of memory cell rows; and a refresh address generator configured to store flags respectively corresponding to the plurality of memory cell rows, generate refresh row addresses respectively corresponding to the plurality of memory cell rows by performing a count operation, and according to the flags, change a refresh period of the plurality of memory cell rows.

Abstract: A memory device includes a memory cell array that includes a plurality of memory cell rows; and a refresh address generator configured to store flags respectively corresponding to the plurality of memory cell rows, generate refresh row addresses respectively corresponding to the plurality of memory cell rows by performing a count operation, and according to the flags, change a refresh period of the plurality of memory cell rows.

Abstract: An on-die termination (ODT) circuit includes a calibration unit, an offset-code generating unit, an adder, and an ODT unit. The calibration unit generates a pull-up code and a pull-down code. The offset-code generates a pull-up offset code and a pull-down offset code based on a mode-register-set signal, the pull-up code, and the pull-down code. The adder adds the pull-up offset code and the pull-down offset code to the pull-up code and the pull-down code, respectively, and generates a pull-up calibration code and a pull-down calibration code. The ODT unit changes ODT resistance in response to the pull-up calibration code and the pull-down calibration code.

Abstract: Provided is a method of detecting a concentrated address of a semiconductor device using an n-bit address. The method includes dividing the n-bit address into k groups, wherein each of n and k is an integer equal to or greater than 2, for each group of the k groups, detecting one or more concentrated sub addresses corresponding to the group, and generating at least one concentrated address by combining the one or more concentrated sub addresses for the k groups.

Abstract: A duty cycle corrector includes a sensing unit, a pad unit, a fuse unit, and a driver unit. The sensing unit generates at least one sensing signal based on the sensed duty cycle ratio of an output signal. The pad unit outputs at least one decision signal based on the at least one sensing signal. The fuse unit generates a duty cycle control signal based on at least one received fuse control signal. The driver unit adjusts a duty cycle ratio of an input signal to generate the output signal based on the duty cycle control signal. The driver unit adjusts the duty cycle ratio of the input signal by adjusting a pull-up strength or a pull-down strength of the input signal based on the duty cycle control signal.

Abstract: An on-die termination (ODT) circuit includes a calibration unit, an offset-code generating unit, an adder, and an ODT unit. The calibration unit generates a pull-up code and a pull-down code. The offset-code generates a pull-up offset code and a pull-down offset code based on a mode-register-set signal, the pull-up code, and the pull-down code. The adder adds the pull-up offset code and the pull-down offset code to the pull-up code and the pull-down code, respectively, and generates a pull-up calibration code and a pull-down calibration code. The ODT unit changes ODT resistance in response to the pull-up calibration code and the pull-down calibration code.

Abstract: A buffer circuit is provided which is insensitive to a duty distortion regardless of the change of operation environment. The buffer circuit includes a current mode logic buffer and a differential-to-single-ended converter. The differential-to-single-ended converter receives first and second differential output signals to generate a single ended output signal and is configured so that an internal control node of the differential-to-single-ended converter is controlled in a negative feedback method to maintain a constant duty ratio of the single ended output signal regardless of the change of operation environment. According to some embodiments, a duty distortion of the single ended output signal due to the change of operation environment such as a process, a voltage, a temperature, etc. is reduced or minimized and thereby performance of the buffer circuit is improved and operation reliability is improved.

Abstract: A duty cycle corrector includes a sensing unit, a pad unit, a fuse unit, and a driver unit. The sensing unit generates at least one sensing signal based on the sensed duty cycle ratio of an output signal. The pad unit outputs at least one decision signal based on the at least one sensing signal. The fuse unit generates a duty cycle control signal based on at least one received fuse control signal. The driver unit adjusts a duty cycle ratio of an input signal to generate the output signal based on the duty cycle control signal. The driver unit adjusts the duty cycle ratio of the input signal by adjusting a pull-up strength or a pull-down strength of the input signal based on the duty cycle control signal.

Abstract: A method of tuning a phase of a clock signal includes performing data training on a plurality of data pins through which data are input and output, in synchronization with a data clock signal; determining one of the data pins to be a representative pin; performing clock and data recovery (CDR) on read data of the representative pin; and adjusting a phase of the data clock signal based on the CDR.

Abstract: An on-die termination circuit includes a termination resistor unit connected to an external pin, and a termination control unit connected to the termination resistor unit. The termination resistor unit provides termination impedance to a transmission line connected to the external pin. The termination control unit varies the termination impedance in response to a plurality of bits of strength code associated with a data rate.

Abstract: A voltage-controlled oscillator includes an oscillating unit configured to output first and second output clock signals at first and second nodes, respectively, the first and second output clock signals having a frequency that is variable in response to a control voltage. An active element unit connected to the oscillating unit is configured to maintain oscillation of the oscillating unit. A bias current generating unit connected to the active element unit at a bias node provides a bias current to the bias node and is adapted to adjust the bias current in response to a control code. First and second capacitor blocks connected to the oscillating unit and the active element unit provide first and second load capacitances, respectively, to the first and second nodes, respectively, in response to the control code.

Abstract: A voltage-controlled oscillator includes an oscillating unit configured to output first and second output clock signals at first and second nodes, respectively, the first and second output clock signals having a frequency that is variable in response to a control voltage. An active element unit connected to the oscillating unit is configured to maintain oscillation of the oscillating unit. A bias current generating unit connected to the active element unit at a bias node provides a bias current to the bias node and is adapted to adjust the bias current in response to a control code. First and second capacitor blocks connected to the oscillating unit and the active element unit provide first and second load capacitances, respectively, to the first and second nodes, respectively, in response to the control code.

Abstract: An internal voltage generator includes a comparison unit, a driving circuit and a bias unit. The comparison unit compares a reference voltage and an internal voltage and is configured to output a comparison voltage, which is based on a difference between the reference voltage and the internal voltage. The driving circuit receives the comparison voltage and an external power supply voltage and is configured to output the internal voltage to an output node in response to the comparison voltage. The bias unit receives the internal voltage and is configured to adaptively adjust a bias current that flows through the bias unit to drive the comparison unit, in consideration of a level of the internal voltage.

Abstract: An on-die termination circuit includes a termination resistor unit connected to an external pin, and a termination control unit connected to the termination resistor unit. The termination resistor unit provides termination impedance to a transmission line connected to the external pin. The termination control unit varies the termination impedance in response to a plurality of bits of strength code associated with a data rate.

Abstract: A method of tuning a phase of a clock signal includes performing data training on a plurality of data pins through which data are input and output, in synchronization with a data clock signal; determining one of the data pins to be a representative pin; performing clock and data recovery (CDR) on read data of the representative pin; and adjusting a phase of the data clock signal based on the CDR.