Abstract: A method of calculating power usage of a lookup table (LUT) implemented on a programmable logic device can include determining input power usage of the LUT and determining output power usage of the LUT. The method further can include determining internal power usage of the LUT. Data rates, LUT configuration, and node capacitance information can be used in determining input, output, and internal power. A measure of power usage for the entire LUT can be provided by summing the input power usage, the output power usage, and the internal power usage.

Abstract: Transition delays in a level shift circuit are equalized by generating a first signal related to the state of the input signal, a second signal inversely related to the state of the input signal, and a third signal that is reciprocal to the second signal. Upon transition of the input signal from a high state to a low state, the third signal is selected for controlling the output until the first signal attains a high state. The first signal is selected for controlling the output when it has reached a high state after the input signal transition. The first signal remains selected upon transition of the input signal from a high state to a low state. Thus, output delays are equalized and reduced to the shortest delay.

Abstract: A dynamic output buffer circuit performs an impedance matching function and a pre-emphasis function by using input and output signals, and consumes relatively less power, occupies a relatively smaller layout area, and dynamically varies an output impedance. The dynamic output buffer circuit dynamically matches an output impedance to the characteristic impedance of a metal line connected to an external circuit, pre-emphasizes at least one input signal, and includes a control circuit and an output circuit. The control circuit matches the output impedance of the dynamic output circuit to the characteristic impedance of the metal line in response to at least one output signal, and outputs a plurality of resistor control signals which are used to pre-emphasize at least one input signal in response to the input signal. The output circuit controls the output impedance and pre-emphasizes the input signal in response to the resistor control signals, and outputs the output signal.

Abstract: Circuits and methods of concatenating first-in-first-out memory circuits (FIFOs). A concatenated FIFO includes first and second FIFOs. The data output terminals of the first FIFO are coupled to the data input terminals of the second FIFO. The read clock of the second FIFO is the system read clock, and the write clock of the first FIFO is the system write clock. Communication between the first and second FIFOs is controlled by the faster of the two system clocks. A control circuit coupled to both the first and second FIFOs has a local clock input terminal coupled to the read clock input terminal of the first FIFO and the write clock input terminal of the second FIFO. The control circuit is driven by status signals from the first and second FIFOs, and generates a read enable signal for the first FIFO and a write enable signal for the second FIFO.

Abstract: Embodiments feature techniques and systems for digitally tuning a crystal oscillator circuit. In one aspect, embodiments feature a method for making a digitally tuned crystal oscillator circuit. The method involves receiving a multi-bit input signal into a digital modulator, modulating the multi-bit input signal with the digital modulator by oversampling or by noiseshaping and oversampling to produce a digitally-modulated output signal having a lower number of bits than the multi-bit input signal. The method also involves coupling a tuning capacitor with the crystal oscillator circuit, and coupling the digitally-modulated output signal from the digital modulator to the crystal oscillator circuit and the tuning capacitor. In some embodiments, the digital modulator can a delta-sigma modulator, a noiseshaping modulator, a delta modulator, a pulse width modulator, a differential modulator, or a continuous-slope delta modulator.

Abstract: A low-power multi-level pulse amplitude modulation (PAM) line driver using variable resistors for transmitting digital data over controlled-impedance transmission lines.

Abstract: A digital frequency multiplier circuit is disclosed. The digital frequency multiplier circuit includes a digitally controlled oscillator (DCO), a phase detector and a control circuit. The DCO generates an internal feedback signal. The phase detector detects a phase difference between the internal feedback signal and an external reference clock signal. Coupled between the phase detector and the DCO, the control circuit adjusts the DCO to align the internal feedback signal with the external reference clock signal after a phase difference between the internal feedback signal and the external reference clock signal has been detected. The control circuit also locks a modulation frequency of the DCO and monitors the state of the digital frequency multiplier circuit in order to maintain the lock.

Abstract: A voltage buffer and the source driver thereof are disclosed. The above-mentioned voltage buffer includes an operational amplifier and an overdriving unit, wherein the operational amplifier outputs an output voltage. The overdriving unit is coupled between an input voltage and the operational amplifier for comparing the input voltage with the output voltage and outputting an overdriving voltage to the positive input terminal of the operational amplifier. Herein if the input voltage is greater than the output voltage, the overdriving voltage is greater than the input voltage; if the input voltage is less than the output voltage, the overdriving voltage is less than the input voltage; if the input voltage is equal to the output voltage, the overdriving voltage is equal to the input voltage.

Abstract: A method and apparatus is provided for the implementation of a process monitor vehicle (PMV) for memory cells. The memory cell PMV is useful in characterizing drive strength of the N-type and P-type field effect transistors (FETs) that are used to implement the memory cell. The memory cell PMV may be used, for example, to measure the amount of margin available for memory cell flips and how process variation affects the memory cell write margin. The memory cell PMV is implemented as a plurality of shift register bits interconnected as a ring oscillator, where each shift register bit is comprised of a memory cell. By adjusting the drive current for each memory cell and measuring the resultant change in oscillation frequency of the ring oscillator, information may be obtained concerning process variation and its effect on memory cell performance.

Abstract: A synchronization system to synchronize modules (TX, RX) in an integrated circuit, such as a VLSI integrated circuit, in which the modules receive respective first and second clock signals (TX_CLK, RX_CLK) having a same frequency but being shifted by a constant and unknown phase difference. The system includes a first latch means for latching and delivering data in synchronism with the first clock signal and second latch means for latching data issued from the first latch means and delivering data in synchronism with the second clock signal, first and second latch means being controlled by first and second control signals (strobe_W, strobe_R) elaborated respectively from said first and second clock signals and one of said first and second control signal being shifted by an amount corresponding at least to the set-up time of at least one of said first and second latch means.

Abstract: A semiconductor memory device is effectively able to adjust operation time for on-die termination (ODT). The semiconductor memory device includes a latency control unit, a control signal generating unit, a trimming control unit, and a termination circuit. The latency control unit produces an ODT driving enable signal by delaying an ODT operation signal from an external circuit during a predetermined latency. The control signal generating unit produces control signals to control a change of waveform of the ODT driving enable signal. The trimming control unit changes the waveform of the ODT driving enable signal in response to the control signals, thereby outputting a ODT driving signal. The termination circuit connects a termination resistance to an impedance adjusting node in response to the ODT driving signal.

Abstract: A level shifter circuit for shifting a voltage level of a logic signal from a first voltage to a second voltage, and a design structure on which the subject circuit reside are provided. An input stage operating in a domain of a first voltage supply includes a first inverter receiving an input signal and providing a first inverted signal. An output voltage level shifting stage operating in a domain of a second voltage supply is coupled to the input stage and providing an output signal having a voltage level corresponding to the second voltage supply domain and a logic value corresponding to the input signal. The level shifter circuit enables voltage level shifting a logic signal from a high to a low operating voltage, or from a low to a high operating voltage. The level shifter circuit enables high frequency operation, providing both fast switching and low capacitance.

Abstract: A semiconductor memory device includes: a termination resistance supply unit connected to a pad to supply termination resistances corresponding to a plurality of control signals; a decoding unit for decoding the plurality of ODT setting signals to output an ODT enable signal and a plurality of decoding output signals; a control signal generating unit for receiving the plurality of decoding output signals to output the plurality of control signals in response to an ODT off signal and a clock signal; and an output control unit for activating one of the plurality of control signals when a read enable detection signal is activated.

Abstract: In a semiconductor device capable of adjusting an output impedance of a first output impedance adjustable output buffer of an external semiconductor device connectable to the semiconductor device, a second output impedance adjustable output buffer is provided. A comparator compares a first output voltage of a real load circuit including the first output impedance adjustable output buffer with a second output voltage of a replica load circuit including the second output impedance adjustable output buffer. An output impedance control circuit transmits an output signal of the comparator to the external semiconductor device to adjust the output impedance of the first output impedance adjustable output buffer, so that the first output voltage is made equal to the second output voltage.

Abstract: The semiconductor integrated circuit includes: a first transistor of a first conductivity type connected between a first power supply and an output node and turned ON according to a first clock to put the output node to a first logic level; a second transistor of a second conductivity type turned ON according to an input signal; a third transistor of the second conductivity type connected in series to the second transistor and turned ON according to a second clock; and a fourth transistor of the first conductivity type connected between the first power supply and the output node and turned ON according to a feedback signal. The second and third transistors are connected between the output node and a second power supply. The fourth transistor is turned from ON to OFF after both the second and third transistors are turned ON.

Abstract: First and second devices may simultaneously communicate bidirectionally with each other using only a single pair of LVDS signal paths. Each device includes an input circuit and a differential output driver connected to the single pair of LVDS signal paths. An input to the input circuit is also connected to the input of the driver. The input circuit may also receive an offset voltage. In response to its inputs, the input circuit in each device can use comparators, gates and a multiplexer to determine the logic state being transmitted over the pair of LVDS signal paths from the other device. This advantageously reduces the number of required interconnects between the first and second devices by one half.

Abstract: Described are systems that employ configurable on-die termination elements that allow users to select from two or more termination topologies. One topology is programmable to support rail-to-rail or half-supply termination. Another topology selectively includes fixed or variable filter elements, thereby allowing the termination characteristics to be tuned for different levels of speed performance and power consumption. Termination voltages and impedances might also be adjusted.

Abstract: A voltage supply control circuit is arranged between a true ground voltage and a pseudo ground line. In an active mode, first and second control signals are at the “H” and “L” levels, respectively. In response to this, a first switch is turned on so that a first node is electrically coupled to a power supply voltage, and attains the “H” level. Further, a second switch is turned on to couple electrically the ground voltage to a second node. In a standby mode, the first and second control signals are at the “L” and “H” levels, respectively. In response to this, a third switch is turned on to couple electrically the first and second nodes together. Since the power supply voltage was electrically coupled to the first node according to the turn-on of the first switch in the active mode, the path of the control signal including the first node to the switch has accumulated charged charges.

Abstract: Methods for improving an implementation of a design in a programmable logic device (PLD). A topological level of the design implementation is determined for each look-up table (LUT) of the PLD. A subset of the LUTs that are on the critical timing paths of the design implementation is determined. For each LUT in the subset at each topological level, a set combinations is determined for assigning signals to the inputs of the LUT. A current assignment of the signals to the LUT inputs is initialized according to the design implementation. For each LUT in the subset at each topological level, the method determines whether a respective assignment for each combination in the set for the LUT improves a timing metric for the LUT relative to the current assignment for the LUT, and the current assignment is updated when the respective assignment improves the timing metric for the LUT.

Abstract: On-chip termination (OCT) calibration techniques are provided that support input/output (IO) banks on an integrated circuit (IC) using OCT controllers. The OCT controllers calibrate the on-chip termination impedance in the IO banks using a shared parallel bus or separate parallel buses. Multiplexers or select logic in each IO bank select control signals from the OCT controllers in response to select signals. According to some embodiments, each of the IO banks on an IC can receive OCT control signals from any of the OCT controllers on the IC.