Abstract: Provided is a semiconductor integrated circuit according to an exemplary aspect of the present invention including a data transmitting circuit that transmits data in parallel through a plurality of signal lines and a data receiving circuit that receives the data. The data transmitting circuit includes a plurality of data output circuits that output the data in a data transmission mode or set an output to a high impedance state in a HiZ mode, a plurality of data selection circuits that select one of the data and fixed data and output the selected data to the data output circuits, and a control circuit that controls the data output circuits to output the fixed data during a period between a time when a mode is switched from the HiZ mode to the data transmission mode and a time when the data output circuits start to output the data.

Abstract: An adjustable impedance circuit includes a calibration module, an impedance module, a first switch module and a second switch module. The calibration module is arranged to generate a calibration signal. The impedance module has a plurality of impedance elements. The first switch module is coupled to the calibration module, and is arranged to receive the calibration signal and make a first portion of the impedance elements be selectively coupled between a differential input port and at least one reference voltage according to the calibration signal. The second switch module is coupled to a common-mode voltage output node, and is arranged to receive a control signal and make a second portion of the impedance elements be selectively coupled between the common-mode voltage output node and the differential input port according to the control signal.

Abstract: Disclosed herein is a semiconductor device that includes a first transistor unit coupled to the data terminal, and a plurality of second transistor units coupled to the calibration terminal. The first transistor unit includes a plurality of first transistors having a first conductivity type connected in parallel to each other so that an impedance of the first transistor unit is adjustable. Each of the second transistor units includes a plurality of second transistors having the first conductivity type connected in parallel to each other so that an impedance of each of the second transistor units is adjustable. The semiconductor device further includes an impedance control circuit that reflects the impedance of each of the second transistor units to the first transistor unit.

Abstract: A method of sharing in use an impedance matching circuit of a memory circuit to perform an initial calibration and a full time refresh mode calibration includes supplying power to the memory circuit, utilizing the impedance matching circuit to perform the initial calibration on the memory circuit, the memory circuit exiting the initial calibration, the memory circuit entering a driving mode, the memory circuit exiting the driving mode every a predetermined interval, utilizing the impedance matching circuit to perform the full time refresh mode calibration on the memory circuit according to a refresh command, an output voltage detection circuit determining a level of an output voltage of the memory circuit, and performing a corresponding operation according to a determination result generated by the output voltage detection circuit.

Abstract: An embodiment of the invention includes dynamically adjusting gain peaking of circuit logic such that error rates are acceptable across various process/voltage/temperature (PVT) ranges. An embodiment uses PVT dependant programming, such as but not limited to resistance compensation (RCOMP) codes, to control impedance compensation logic, such as but not limited to a Continuous Time Linear Equalization (CTLE) circuit. The PVT programming may be used to control gain peaking amplitude and gain peaking frequency across ranges of different PVTs. As a result, error performance is not impaired across different PVT corners and gain peaking is more consistent across different PVT corners. Other embodiments are included herein.

Abstract: A semiconductor memory device is disclosed that includes an ODT circuit configured to be connected to a bus which transmits a data signal or a data strobe signal between a memory block and an input-output terminal; a first switch configured to be inserted into the bus between the memory block and the ODT circuit; a mode controller configured to switch off the first switch during a test of the memory block; and an oscillator configured to be connected to the ODT circuit, wherein a test signal is supplied to the ODT circuit from the oscillator during the test of the memory block.

Abstract: To provide a circuit used for a shift register or the like. The basic configuration includes first to fourth transistors and four wirings. The power supply potential VDD is supplied to the first wiring and the power supply potential VSS is supplied to the second wiring. A binary digital signal is supplied to each of the third wiring and the fourth wiring. An H level of the digital signal is equal to the power supply potential VDD, and an L level of the digital signal is equal to the power supply potential VSS. There are four combinations of the potentials of the third wiring and the fourth wiring. Each of the first transistor to the fourth transistor can be turned off by any combination of the potentials. That is, since there is no transistor that is constantly on, deterioration of the characteristics of the transistors can be suppressed.

Abstract: An output circuit includes a first circuit that generates a first output voltage based on a resistance ratio, on the basis of a reference voltage, a second circuit that compares the first output voltage with a source voltage of a second transistor that sets a second output voltage of the output signal, and generates an output gate voltage for causing the first transistor to output the second output voltage, and a third circuit that controls a timing at which the output gate voltage is applied to the first transistor, on the basis of an input control signal.

Abstract: An integrated circuit includes an output buffer and a control circuit. The output buffer has a signal input, a signal output, and a set of control inputs. The output buffer has an output buffer delay, and a driving strength adjustable in response to control signals applied to the set of control inputs. The control circuit is connected to the set of control inputs of the output buffer. The control circuit uses first and second timing signals to generate the control signals, and includes a reference delay circuit that generates the first timing signal with a reference delay, and a delay emulation circuit that generates the second timing signal with an emulation delay that correlates with the output buffer delay.

Abstract: A comparison circuit for detecting impedance mismatch between pull-up and pull-down devices in a circuit to be monitored includes a comparator operative to receive first and second signals and to generate, as an output, a third signal indicative of a difference between the first and second signals. A first signal generator is operative to generate the first signal indicative of a difference between reference pull-up and pull-down currents that is scaled by a prescribed amount. The reference pull-up current is indicative of a current flowing through at least one corresponding pull-up transistor device in the circuit to be monitored. The pull-down reference current is indicative of a current flowing through at least one corresponding pull-down transistor device in the circuit to be monitored.

Abstract: A method of buffering data from core circuitry includes generating a first sourcing control signal responsive to indication signals indicating an operating voltage and output data, generating a second sourcing control signal responsive to the indication signals, and applying the operating voltage to an output terminal in response to the first sourcing control signal and the second sourcing control signal. The first sourcing control signal swings between the operating voltage and a reference voltage. The reference voltage is a signal selected from among a plurality of internal voltages in response to selection signals generated as a result of decoding the indication signals.

Abstract: An integrated circuit chip includes a first single ended type buffer configured to receive a first signal through a first pad, a second single ended type buffer configured to receive a second signal through a second pad, a differential type buffer configured to receive a third signal through the first pad and the second pad, a strobe input unit configured to receive a strobe signal synchronized with the third signal inputted to the first pad and the second pad, and a buffer control unit configured to control activation of the first and second single ended type buffers and the differential type buffer in response to the strobe signal.

Abstract: An inverter-type high speed driver circuit having a first inverter branch and a second inverter branch wherein each of the inverter branches comprising a parallel circuit of a serial connection of a first impedance tuning unit and a respective first clocking transistor and a serial connection of a second impedance tuning unit and a respective second clocking transistor. The impedance tuning units are configured to adapt the conductivity of the respective inverter branch to set the output impedance of the driver circuit and each of the impedance tuning units is controlled in accordance with a data stream.

Abstract: A system having an input and output buffer includes a dynamic driver reference generator to generate dynamic driver reference signals based on a data signal and an IO buffer supply voltage, a level shifter to generate level shifted signals based, in part, on the dynamic driver reference signals, and a driver having at least one stress transistor. The driver dynamically adjusts a voltage across the stress transistor based on at least one of dynamic driver reference signals, the level shifted signals, and a current state of an IO pad.

Abstract: In one embodiment, an internal buffer may be provided within an integrated circuit (IC) to convert a signal to an output current to be output via a pin of the IC, under control of a switch which can be controlled based on a configuration setting of the IC, and may selectively directly couple the signal to the pin when the IC is coupled to an external driver circuit.

Abstract: The invention provides a semiconductor device having a current input type pixel in which a signal write speed is increased and an effect of variations between adjacent transistors is reduced. When a set operation is performed (write a signal), a source-drain voltage of one of two transistors connected in series becomes quite low, thus the set operation is performed to the other transistor. In an output operation, the two transistors operate as a multi-gate transistor, therefore, a current value in the output operation can be small. In other words, a current in the set operation can be large. Therefore, an effect of intersection capacitance and wiring resistance which are parasitic on a wiring and the like do not affect much, thereby the set operation can be performed rapidly. As one transistor is used in the set operation and the output operation, an effect of variations between adjacent transistors is lessened.

Abstract: Architecture for VBUS pulsing in an Ultra Deep Sub Micron (UDSM) process for ensuring USB-OTG (On The Go) session request protocol, the architecture being of the type wherein at least a charging circuit is deployed, uses a diode-means connected in a forward path of the charging circuit. The architecture might include a diode-divider including nodes and connected from VBUS in said charging circuit. One embodiment uses both charging and discharging circuits comprising transistors. The charging circuit transistor might comprise a PMOS transistor and the discharging circuit transistor might comprise a NMOS transistor. The architecture might include a three resistance string of a total resistance value approximating 100K Ohms connected between said VBUS and ground, wherein the discharging circuit transistor might comprise a drain extended NMOS transistor. The charging and discharging circuit transistors have VDS and VGD of about 3.6V, whereby high VGS transistors are not needed.

Abstract: This document discusses, among other things, output slew rate control. Methods and structures are described to provide slew rate control of an output driver circuit such as a DRAM output driver on a die. A selectable combination of series coupled transistors are configured as a parallel array of complementary inverter pairs to provide a divided voltage to a calibrator. The calibrator is configured to respond to a differential voltage to adjust the divided voltage such that the differential voltage is forced to zero. The calibrator outputs a plurality of discrete signals from an up/down counter to toggle the individual transistors of the parallel array to increase and decrease a collective current. In some embodiments, transistor channel currents are modulated to step-adjust a voltage based on a ratio associated with a static resistance. In various embodiments, the divided voltage is an analog voltage based on a resistance associated with trim circuitry.

Abstract: Embodiments of a memory controller are described. This memory controller communicates signals to a memory device via a signal line, which can be a data signal line or a command/address signal line. Termination of the signal line is divided between an external impedance outside of the memory controller and an internal impedance within the memory controller. The memory controller does not activate the external impedance prior to communicating the signals and, therefore, does not deactivate the external impedance after communicating the signals. The internal impedance of the memory controller can be enabled or disabled in order to reduce interface power consumption. Moreover, the internal impedance may be implemented using a passive component, an active component or both. For example, the internal impedance may include either or both an on-die termination and at least one driver.

Abstract: A transmitter includes a power amplifier (PA) and a direct current (DC) voltage tuning circuit. The PA is arranged for receiving a radio-frequency (RF) clock derived from a clock source, and producing an output signal according to at least the RF clock. The DC voltage tuning circuit is arranged for tuning at least one DC voltage supplied to the PA for pulling mitigation of the clock source. A method of pulling mitigation of a source clock by a power amplifier (PA) includes adjusting a direct current (DC) voltage supplied to the PA.

Abstract: The driver circuit includes a first controlling circuit that outputs, to a gate of the auxiliary pMOS transistor, a first controlling signal that rises in synchronization with a rising of the first pulse signal and falls after a delay from a falling of the first pulse signal. The driver circuit includes a second controlling circuit that outputs, to a gate of the auxiliary nMOS transistor, a second controlling signal that rises in synchronization with a rising of the second pulse signal and falls after a delay from a falling of the second pulse signal.

Abstract: I/O circuits and a method for transmitting different types of I/O signals are disclosed. An embodiment of the I/O circuit comprises multiple transistors with multiple switches coupled to the transistors. The switches may be used to selectively couple the transistors to a power source or to another transistor to form different transistor configurations. The transistors may be configured to form a parallel configuration or a stacked configuration. Stacking up transistors may reduce voltage swings in the transistors and subsequently reduce degradation in the transistors.

Abstract: Apparatus and methods advantageously maintain transistors of open-drain differential pairs biased in the saturation region when “active,” rather in than the triode or linear region. The biasing techniques are effective over a broad range of process, voltage, and temperature (PVT) variations. By controlling a high voltage level used to drive the gate of a transistor of the differential pair, the biasing of the transistor in the saturation region is maintained. In one embodiment, the low voltage level used to cut off the transistor of the differential pair is also controlled. These techniques advantageously permit differential drivers to exhibit relatively large output swings, relatively high edge rates, relatively high return loss, and relatively good efficiency.

Abstract: Each of a plurality of memories includes a terminating resistor for preventing signal reflection, and a memory control circuit includes an ODT control circuit for driving the terminating resistor of each memory, and a selector for selecting, from memories except for a memory to be accessed, at least one memory for which driving of the terminating resistor is to be suppressed, in accordance with the memory to be accessed.

Abstract: It is an object to suppress deterioration in characteristics of a transistor in a driver circuit. A driver circuit includes a first transistor, a second transistor including a gate and one of a source and a drain to which a second signal is inputted, a third transistor whose gate is electrically connected to one of a source and a drain of the first transistor and which controls whether a voltage state of an output signal is set or not by being turned on/off, and a fourth transistor whose gate is electrically connected to the other of the source and the drain of the second transistor and which controls whether a voltage state of an output signal is set or not by being turned on/off.

Abstract: Provided is a semiconductor integrated circuit according to an exemplary aspect of the present invention including a data transmitting circuit that transmits data in parallel through a plurality of signal lines and a data receiving circuit that receives the data. The data transmitting circuit includes a plurality of data output circuits that output the data in a data transmission mode or set an output to a high impedance state in a HiZ mode, a plurality of data selection circuits that select one of the data and fixed data and output the selected data to the data output circuits, and a control circuit that controls the data output circuits to output the fixed data during a period between a time when a mode is switched from the HiZ mode to the data transmission mode and a time when the data output circuits start to output the data.

Abstract: An exclusive-or circuit includes a pass gate controlled by a second input node. The pass gate is connected to pass through a version of a logic state present at a first input node to an output node when so controlled. A transmission gate is controlled by the first input node. The transmission gate is connected to pass through a version of the logic state present at the second input node to the output node when so controlled. Pullup logic is controlled by both the first and second input nodes. The pullup logic is connected to drive the output node low when both the first and second input nodes are high. An exclusive-nor circuit is defined similar to the exclusive-or circuit, except that the pullup logic is replaced by pulldown logic which is connected to drive the output node high when both the first and second input nodes are high.

Abstract: Techniques are provided for transmitting signals through a differential interface between circuits in different power supply domains. A driver circuit in a first power supply domain converts single-ended signals into differential signals. The driver circuit then transmits the differential signals to a receiver circuit in a second power supply domain. The receiver circuit converts the differential signals back into single-ended signals for transmission to circuit elements in the second power supply domain. The differential interface reduces the transmission of noise between circuit elements in the first power supply domain and circuit elements in the second power supply domain.

Abstract: An integrated circuit includes an output buffer and a control circuit. The output buffer has a signal input, a signal output, and a set of control inputs. The output buffer has an output buffer delay, and a driving strength adjustable in response to control signals applied to the set of control inputs. The control circuit is connected to the set of control inputs of the output buffer. The control circuit uses first and second timing signals to generate the control signals, and includes a reference delay circuit that generates the first timing signal with a reference delay, and a delay emulation circuit that generates the second timing signal with an emulation delay that correlates with the output buffer delay.

Abstract: A voltage mode transmitter equalizer has high efficiencies, yet consumes substantially constant supply current from the power supply and provides constant back-match impedance. The voltage mode transmitter equalizer is configured such that the output voltage of the signal to be output on a pair of transmission lines can be controlled according to the input data, but its return impedance is substantially matched to the differential impedance of the transmission lines and it draws substantially constant supply current from the power supply regardless of the output voltage of the signal. Further, an equalizer for a voltage-mode transmitter provides fine-granularity equalization settings by employing a variable pull-up conductance and a variable pull-down conductance. Conductance is varied by selectively enabling a plurality of conductance channels, at least some of which have resistance values that are distinct from one another.

Abstract: A circuit for driving a gate of a power MOS transistor includes an adaptive pull-up unit and an adaptive pull-down unit. The adaptive pull-up unit is connected between a first power source voltage and the gate of the power MOS transistor. The adaptive pull-up unit maximizes pull-up current driving ability. The adaptive pull-down unit is connected between a second power source voltage and the gate of the power MOS transistor. The adaptive pull-down unit maximizes pull-down current driving ability.

Abstract: A multi-stage digitally-controlled power amplifier (DPA) includes a radio-frequency (RF) clock input, an amplitude control word (ACW) input, a plurality of drivers, and an output stage. The RF clock input is arranged for receiving an RF clock. The ACW input is arranged for receiving a digital ACW signal. The drivers are coupled to the RF clock, and arranged for producing a plurality of intermediate signals, wherein at least one driver of the drivers is responsive to at least one bit of the digital ACW signal. The output stage is coupled to the intermediate signals, and arranged for producing an output signal.

Abstract: A source-series terminated (‘SST’) driver circuit that includes: one or more data signal inputs; one or more control signal inputs; a driver output; and a plurality of driver cells, the driver cells coupled in parallel to one another, outputs of the driver cells coupled together to form the driver output of the SST driver circuit, where output resistance of the SST driver circuit varies in dependence upon activation of one or more of the parallel driver cells, activation of each driver cell controlled by control signals received at the control signal inputs.

Abstract: An electrical circuit comprising a line driver for providing Ethernet signals is disclosed. The line driver comprises a voltage mode line driver for producing 1000BT and 100BT Ethernet signals and an active output impedance line driver arranged parallel to the voltage mode line driver. The line driver is capable of producing 1000BT or 100BT or 10BT Ethernet signals, wherein either the voltage mode line driver or the active impedance line driver is active.

Abstract: Methods, circuits, and systems for termination calibration are provided. Differential input buffer circuitry is used to compare a signal level at an input/output pad and a first reference signal level. Control circuitry is used to control a controllably variable impedance based on the output of the differential input buffer circuitry. Optionally, second differential input buffer circuitry is used to compare the signal level at the input/output pad to a second reference signal level. The control circuitry is used to control the controllably variable impedance based on the output of both the first and the second differential input buffer circuitry.

Abstract: Provided is a semiconductor integrated circuit according to an exemplary aspect of the present invention including first and second transmitter-receivers that execute transmission and reception of data through a signal line. The first transmitter-receiver includes a first termination circuit that includes a first resistor and a first switch, the first resistor being provided between a first power supply terminal and the signal line, the first switch controlling a current flowing through the first resistor to be turned on and off, and a control circuit that outputs a first control signal to the first termination circuit so that the first switch is turned on when the first transmitter-receiver receives data, the first switch is turned off when the first transmitter-receiver transmits the data, and the first switch is continuously on during a first predetermined period after receiving the data when the first transmitter-receiver further receives another data after receiving the data.

Abstract: According to one embodiment, a clamp transistor is inserted in series between a P-channel field effect transistor and an N-channel field effect transistor and an intermediate level between a high potential supplied to a source of the P-channel field effect transistor and a low potential supplied to a source of the N-channel field effect transistor is input into a gate of the clamp transistor to clamp a drain potential of the N-channel field effect transistor.

Abstract: Disclosed is a high-swing voltage-mode transmitter or line driver. The transmitter can operate over a wide range of supply voltages. Increasing the available output swing merely involves increasing the supply voltage; the circuit adapts to maintain the desired output impedance. This allows for a tradeoff between output amplitude and power consumption. Another advantage of the proposed architecture is that it compensates for process, voltage, and temperature (PVT) and mismatch variations so as to keep rise and fall times matched. This feature reduces common-mode noise and hence EMI in systems in which the transmitter is used.

Abstract: High resolution output drivers having a relatively small number of sub-driver branches or slices each having nominal impedances substantially larger than a quantization step and that incrementally differ from one another by an impedance step substantially smaller than a quantization step. In one implementation, such “differential” or “non-uniform” sub-driver slices implement respective elements of an n choose k equalizer, with each such differential sub-driver slice being implemented by a uniform-element impedance calibration DAC. In another implementation, each component of a uniform-slice equalizer is implemented by a differential-slice impedance calibration DAC, and in yet another implementation, each component of a differential-slice equalizer is implemented by a differential-slice impedance calibration DAC.

Abstract: A semiconductor device includes a first signal delay block configured to delay a first edge of an input signal with varying delay amounts, maintain a second edge of the input signal, and output at least one first driving signal, a second signal delay block configured to delay the second edge of the input signal with the varying delay amounts, maintain the first edge of the input signal, and output at least one second driving signal, and an output pad driving block configured to drive a data output pad with a first voltage in response to the first driving signal and drive the data output pad with a second voltage in response to the second driving signal.

Abstract: A buffer circuit includes a first node that receives a first voltage, a second node, an output node that receives the first voltage, a first transistor coupled between the first node and the second node, the first transistor having a backgate receiving the first voltage, and a second transistor coupled between the second node and the output node, the second transistor having a backgate receiving a second voltage being higher than the first voltage.

Abstract: A circuit includes a plurality of logic gates and a drive circuit. The plurality of logic gates are coupled between a first supply node and a second supply node. Each logic gate has at least one input and consumes a short circuit current during a logic state transition. The drive circuit is coupled to the inputs of the plurality of logic gates to deliver a copy of an input signal to each logic gate, wherein the input signal copies arrive at the inputs of the logic gates at substantially different times. The circuit may be incorporated in a touch screen panel and a display.

Abstract: A method is provided for controlling a data transmission device that includes at least one fractional-sized subdriver. The method includes enabling at least one subdriver and driving a differential signal pair output. Also provided is a device with an output driver having a plurality of subdrivers where at least one subdriver is fractional-sized. The device also includes a de-emphasis portion configured to enable and disable the subdrivers. The device is configured to drive an output data signal. Also provided is a computer readable storage device encoded with data for adapting a manufacturing facility to create an apparatus such as the device. Also provided is an apparatus that includes an output driver with at least one fractional-sized subdriver and a de-emphasis portion configured to enable and disable the subdrivers of the output driver. The output driver is configured to drive a differential output data signal.

Abstract: Apparatuses and methods for driving input data signals onto signal lines as output data signals are disclosed. An example apparatus includes a detection circuit, a driver adjust circuit, and a data driver. The detection circuit is configured to detect a characteristic(s) of a group of input data signals to be driven onto adjacent signal lines. A characteristic could be, for example, a particular combination of logic levels and/or transitions for, the group of input data signals. The driver adjust circuit is configured to provide a driver adjustment signal based at least in part on a detection signal, that is provided by the detection circuit. A data driver is configured to drive a respective one of the group of input data signals as a respective one of the output data signals, wherein the data driver is adjusted based at least in part on the driver adjustment signal.

Abstract: A voltage mode driver circuit able to achieve a larger voltage output swing than its supply voltage. The voltage mode driver circuit is supplemented by a current source or “current booster.” The circuit includes a first inverter, a second inverter, and a current source. The first inverter receives a first input and output a signal at anode. The second inverter receives another input outputs at the same output node. The current source is serially coupled to the output node via a first switch, the first switch receiving an input at the first input.

Abstract: A semiconductor device includes a core circuit including an integrated circuit; output drivers, each including sub-drivers to output digital data transferred from the core circuit, as output data; and a selector that selects a sub-driver to be driven from among the plurality of sub-drivers. Each of the sub-drivers includes: an output transistor connected between a first power supply and an output wiring line to allow the output data to rise or fall according to the digital data; and a switching transistor and a slew-rate control transistor which are connected in series between a gate of the output transistor and a second power supply. The switching transistor turns on or off the output transistor according to the digital data. A gate potential adjusted to determine a slew rate for rise or fall of the output data is selectively provided by the selector to each slew-rate control transistor.

Abstract: In a semiconductor device having a terminal connected to an internal portion, a termination circuit for providing on-die termination for the terminal of the device. The termination circuit comprises a plurality of transistors, including at least one NMOS transistor and at least one PMOS transistor, connected between the terminal and a power supply; and control circuitry for driving a gate of each of NMOS transistor with a corresponding NMOS gate voltage and for driving a gate of each PMOS transistor with a corresponding PMOS gate voltage, the control circuitry being configured to control the NMOS and PMOS gate voltages so as to place the transistors in an ohmic region of operation when on-die termination is enabled. The power supply supplies a voltage that is less than each said NMOS gate voltage and greater than each said PMOS gate voltage.

Abstract: A level shifter includes first and second input terminals, first and second output terminals, first pull-down circuitry operable to pull down one of the first and second output terminals responsive to signals present on the first and second input terminals, first pull-up circuitry operable to pull up the first output terminal responsive to a signal present on the second output terminal or pull up the second output terminal responsive to a signal present on the first output terminal, and second pull-up circuitry operable to pull up one of the first and second output terminals responsive to the signals present on the first and second input terminals.

Abstract: Apparatus and methods are provided for generating output signals representative of bits of serial data. A transmitter includes driver circuitry configured to generate an output signal at an output node and an allocation control module coupled to the driver circuitry. The driver circuitry includes a plurality of driver legs configured to generate the output signal based on a plurality of data bits. The allocation control module is configured to allocate a respective subset of the plurality of driver legs to a respective data bit of a plurality of data bits, wherein the each subset generates a component of the output signal that is influenced by its respective data bit.

Abstract: An on-die termination circuit is capable of increasing a resolution without enlargement of a chip or a layout size. The on-die termination circuit includes a control means, a termination resistance supply means, a code signal generating means. The control means sequentially generates a plurality of control signals in a response to a driving signal. The termination resistance supply means supplies a termination resistance in response to a coarse code signal having a plurality of bits and a fine code signal having a plurality of bits. The code signal generating means controls the fine code signal and the coarse code signal in response to the plurality of the control signals in order that the termination resistance has a level which is correspondent to an input resistance.