Teradyne, Inc.

Rambus Inc.

Inphi Corporation

Other

Cosmin Iorga

James Lawrence Gorecki

Alan B Hussey

Marcial K Chua

Jiayun Zhang

Sriram Narayan

Kuok Y Ling

Panduka Wijetunga

Jeffrey C Yen

Srinivas Satish Babu Bamdhamravuri

Abhishek Desai

Lucian Maria

Gary Evans

Marcial Chua

Philip Lu

Ruibing Zhang

A pulse filter circuit is configured to eliminate pulses that are less than a specified duration and pass those that are greater than the specified duration. A buffer receives a signal and applies the buffered signal to a resistance-capacitance charging-discharging circuit (e.g., RC filter). When the output of the RC filter has, in response to the buffered signal, charged or discharged, as appropriate, to cause the output of a slicer to change, logic circuitry controls switching circuitry to pull the output of the RC filter to be fully charged or discharged, respectively. In this manner, pulses that are too short to charge/discharge the RC filter enough to cross the threshold of the slicer do not reach the slicer circuit output, but pulses that are long enough to cross the slicer threshold are transmitted by the slicer.

Pulse filter

Described is an integrated circuit with a driving amplifier that transmits a signal over a link (e.g. a wire) by raising and lowering a voltage on the link. A reference oscillator provides an error measure for the rate at which the voltage transitions between voltages, the slew rate. Slew-rate calibration circuitry adjusts the driving amplifier responsive to the error measure.

Methods and circuits for slew-rate calibration

A memory controller conveys a clock signal with command and address signals to a registered clock driver (RCD) on a memory module. A controller-side chip interface on the RCD supports both source-synchronous and filtered clocking for receipt of the command and address signals, the selection between the two clocking schemes dependent upon the noise environment impacting the clock and command/address signals. If the noise is predominantly correlated, then the chip interface is placed in a source-synchronous clocking mode. If the noise is predominantly uncorrelated, then the chip interface is placed in a filtered clocking mode that filters out uncorrelated noise from the clock signal.

Circuits and methods for sample timing in correlated and uncorrelated signaling environments

Measurement of power distribution network (PDN) Z-parameters and S-parameters of a programmable logic device (PLD), such as field programmable gate array (FPGA) or complex programmable logic device (CPLD), is performed by configuring and using only logic blocks and I/O blocks commonly available in any existing programmable logic device, without the need of built-in dedicated circuits. The measured models include the PDN elements on the PLD die, PLD package, and PCB. The S-parameter and Z-parameter models can be then used in circuit simulation tools to evaluate the power supply noise in the PLD logic core and the timing jitter in the PLD I/O data links.

FPGA configured vector network analyzer for measuring the z parameter and s parameter models of the power distribution network in FPGA systems

Apparatus to implement several high performance phase interpolators are disclosed. Some embodiments are directed to a full-wave integrating phase interpolation core comprising two pairs of in-phase and quadrature-phase current DACs arranged in a cascode architecture to drive an integrating capacitor and produce an interpolation voltage waveform. The current DACs are biased, weighted, and controlled by in-phase and quadrature-phase input clocks to yield an interpolation waveform that presents a phase value between the phases of the input clocks. Some embodiments deploying the interpolator core use feedback circuitry and reference voltages to adjust the common mode and amplitude of the interpolation voltage waveform to obtain both optimal performance and operation within the interpolator linear region or output compliance range. Both the single-core and dual-core implementations, as well as other implementations of the interpolator core, exhibit high power supply rejection, highly linear interpolation, a wide frequency range, and low cost duty cycle correction.

Phase interpolator

A method and device for dynamically updating a phase interpolator circuit module using a phase update circuit module. The method can include interpolating a set of input clock phases based on a phase interpolator code input and sequentially updating the rising edge generator and falling edge generator starting from a synchronizer update signal. The dynamic sequential update involves disabling a rising edge ramp signal while updating a rising edge interpolator and generating old clock out falling edge according to an old phase interpolator code input, disabling a falling edge ramp signal while updating a falling edge interpolator, enabling the rising edge ramp signal and generating a new clock out rising edge according to a new phase interpolator code input, and enabling the falling edge ramp signal and generating a new clock out falling edge according to the new phase interpolator code input.

Dynamic update technique for phase interpolator device and method therefor

A delay circuit device configured for delay adjustment monotonicity and method of operating therefor. This delay circuit device is configured with hybrid coarse-fine delay cells and uses a sequence of these delay cells activated in a way that builds-up the delay as a sequence of fine steps until it reaches the coarse delay value. This configuration allows for the continuing build of propagation delay by adding the fine steps of the following delay cells. In this manner, the monotonicity of the signal delay circuit is ensured by the architecture independent from device mismatch, thus eliminating problems with conventional delay circuits such as gaps and overlaps specific the these conventional delay cells.

Method and circuit for delay adjustment monotonicity in a delay line

A driver integrated circuit (IC) device. The driver device can include a front-end module, a pre-driver module, and a driver module coupled to a transmission line path. The pre-driver module can be coupled to the front-end module and can include one or more delay adjust capacitor modules, and one or more pull-down control modules. The driver module can be coupled to the pre-driver module, the driver module including one or more pull-down control logic modules. This driver device can configured in several implementations to provide control and programmability of a driver slew rate to maximize a signal integrity eye opening.

Slew-rate control and waveshape adjusted drivers for improving signal integrity on multi-loads transmission line interconnects

A method and device for dynamically updating a phase interpolator circuit module using an update control circuit module. The method can include providing the phase interpolator with a set of input clock phases to produce a clock signal. The update control module can generate a blanking signal in response to an update signal and apply an update process that stops an old clock output signal after a last clock pulse. The update control module can then update phase select multiplexers for a rising edge integrator and falling edge integrator according to a new phase interpolator code. The update control module can determine a phase jump code and then release the blanking signal during a discharge time interval of the rising edge integrator following a phase jump duration according to the phase jump code. Afterwards, the phase interpolator module can generate the new clock output signal without producing glitches.

Phase interpolator device using dynamic stop and phase code update and method therefor

On-die measurement of power distribution impedance frequency profile of a programmable logic device (PLD), such as field programmable gate array (FPGA) or complex programmable logic device (CPLD), is performed by configuring and using only logic blocks resources commonly available in any existing programmable logic device, without the need of built-in dedicated circuits. All measurements are done inside the programmable logic device without the need of external instruments. The measurement method can be used during characterization to select decoupling capacitors or for troubleshooting existing systems, after which the programmable logic device may be reconfigured to perform any other user-defined function.

Method and system for measuring the impedance of the power distribution network in programmable logic device applications

An embodiment of the present invention provides a system for detecting a phase-shifted signal at high frequencies in data and clock recovery circuitry. An up-pulse generator, in one embodiment, provides output pulses having a duration exceeding the duration of input pulses upon detection of a phase-shifted signal leading the reference signal. A down-pulse generator provides output pulses having a duration exceeding the duration of input pulses upon detection of a phase-shifted signal lagging the reference signal.

Method and apparatus for 0/180 degree phase detector

A digital-to-analog converter (DAC) includes coarse interpolation DACs configured to produce a current range based on an input digital signal, and fine interpolation DACs configured to produce an output current that is based on an input digital signal and that is within the current range produced by the coarse interpolation DACs.

Interpolation digital-to-analog converter

A high-speed digital multiplexer is disclosed, The multiplexer includes a plurality of input pins for receiving a plurality of digital input signals ad switching circuitry coupled to the input pins. The switching circuitry has respective outputs coupled to a common node and is operative to enable a selected one of the plurality of input pins, The multiplexer further includes a local signal converter having a circuit branch set to a common voltage. The branch is connected to the common node to sense changes in current corresponding to an input signal received by an enabled input pin. An output pin is coupled to the local signal converter, whereby the local signal converter is operative to produce voltage changes at the output corresponding to the sensed current changes.

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Newbury Park, CA, United States of America

Cosmin Iorga