Abstract: A simultaneous bidirectional port circuit includes a current mode output driver for driving an output node and a current mode return driver for driving a differential receiver. Variable impedance termination devices are included to provide terminations for both the current mode output driver and current mode return driver. A control circuit and method set the impedance value of the variable impedance termination devices by comparing voltage values at the output of the current mode output driver and current mode return driver.

Abstract: A simultaneous bi-directional I/O circuit includes a first MUX in the reference select circuitry and a second, matching MUX in the pre-driver stage of the output buffer. In normal mode, the first MUX passes the driven data output signal, which controls the threshold of the differential receiver circuit between two different non-zero voltage levels, so that the receiver circuit can properly decode an incoming signal at the I/O node or pin. In an AC switching state or loopback test mode, the first MUX de-selects the driven data output signal from controlling the receiver circuit. This allows the receiver circuit to decode outgoing data that is being looped back as incoming data. The second MUX enables the reference select circuitry to switch at a rate that matches the output slew rate in order to provide high-speed operation. Also described are an electronic system, a data processing system, and various methods of testing simultaneous bi-directional I/O circuits.

Abstract: A clock deskew method includes receiving a data signal and a clock signal, processing the data signal to generate a jitter characterization parameter, shifting the clock signal by about 90° from the jitter characterization parameter to generate a sampling clock signal, and sampling the data signal with the sampling clock signal to generate a deskewed data signal. A clock deskew unit includes a clock unit, a sampling unit, and a deskew unit. The deskew unit includes a jitter characterization unit that generates a jitter characterization parameter. The jitter characterization parameter establishes a phase location for aligning a clock signal. Shifting the clock signal by about 90° from the phase location of the jitter characterization parameter provides a location for sampling a data signal to generate a deskewed data signal.

Abstract: A multiple input, fully differential amplifier. Embodiments make use of complementary differential transistors pairs connected with cascode transistors to form folded cascode pairs, to achieve wide common mode range, high common mode rejection, and high gain.

Abstract: A simultaneous bidirectional port circuit includes a current mode output driver for driving an output node and a current mode return driver for driving a differential receiver. Variable impedance termination devices are included to provide terminations for both the current mode output driver and current mode return driver. A control circuit and method set the impedance value of the variable impedance termination devices by comparing voltage values at the output of the current mode output driver and current mode return driver.

Abstract: A circuit samples a voltage on a simultaneous bi-directional bus, and subtracts an outbound voltage to determine an inbound voltage. Sampling capacitors are variable to adjust for matching time constants. A mechanism is provided to sample error voltages over clock phase variations and sampling capacitor values.

Abstract: A discrete-time analog filter, where a filter tap of the filter comprises a voltage-to-current converter and a current multiplier in a single stage so as to provide a current signal indicative of a weighted sampled voltage signal. The current signals are summed by one or more active cascode differential latches to provide an output logic signal indicative of the filtered output. The discrete-time analog filter finds applications in channel equalization, and is suitable for high data rates and low voltage applications. The voltage and current signals may be differential.

Abstract: A memory system provides includes multiple memory devices or banks of memory devices that are assigned frequency pass-bands. Each memory device includes frequency translation circuitry to up-convert and down-convert data signals to and from the assigned frequency pass-band. Some embodiments include simultaneous bidirectional communications between memory devices and a controller by assigning multiple frequency pass-bands to each memory device or bank of memory devices. A memory system substrate is provided with bandpass filters between memory device footprints and other device footprints.

Abstract: A simultaneous bidirectional port coupled to a bus combines a synchronization circuit and a data transceiver circuit. The combination data and synchronization transceiver circuit synchronizes the port with another simultaneous bidirectional port coupled to the same bus. The combination data and synchronization transceiver circuit includes a driver with a variable output current and a variable output resistance. Prior to synchronization, the driver has a low output current and low output resistance. When the simultaneous bidirectional port is ready to communicate, the variable output resistance is increased. When both simultaneous bidirectional ports are ready, the variable output resistance is set to properly terminate the line, and the variable output current is set to provide a desired voltage swing.

Abstract: According to an embodiment of the invention a circuit that is to be coupled to a reference voltage line. The circuit includes a noise coupling circuit that is to couple noise from the circuit to a reference voltage line based upon whether a driver is driving a data line.

Abstract: A current mode driver includes a tail current device, a differential pair of input transistors, cascode output transistors, and pre-charge circuits to charge cascode nodes between the differential pair of input transistors and the cascode output transistors. The current mode driver is driven by CMOS drivers that alternately turn the input transistors on and off. A wide-swing bias circuit provides bias voltages for the current mode driver. This bias voltage for the tail current device is closely matched to provide current matching between the bias circuit and the current mode driver.

Abstract: A digital interconnect system transmits pulses across a differential transmission line in response to transitions in an input data signal.

Abstract: A device includes a bus, a first transmitter connected to the bus and configured to transmit a first signal over the bus in a first frequency band, a second transmitter connected to the bus and configured to transmit a second signal over the bus in a second frequency band at the same time that the first transmitter is transmitting the first signal, a first receiver connected to the bus and configured to receive the first signal transmitted over the bus in the first frequency band, and a second receiver connected to the bus and configured to receive the second signal transmitted over the bus in the second frequency band. The first frequency band and the second frequency band occupy different portions of the frequency spectrum.

Abstract: A simultaneous bidirectional port coupled to a bus combines a synchronization circuit and a data transceiver circuit. The combination data and synchronization transceiver circuit synchronizes the port with another simultaneous bidirectional port coupled to the same bus. The combination data and synchronization transceiver circuit includes a driver with a variable output current and a variable output resistance. Prior to synchronization, the driver has a low output current and low output resistance. When the simultaneous bidirectional port is ready to communicate, the variable output resistance is increased. When both simultaneous bidirectional ports are ready, the variable output resistance is set to properly terminate the line, and the variable output current is set to provide a desired voltage swing.

Abstract: A method for minimizing jitter using substantially matched, controlled, delay elements is disclosed. The method includes generating an internal loop-timing reference, and controlling elements outside of the loop with the internal loop-timing reference generated. In one embodiment the outside elements are substantially identical to those internal to the closed-loop. Controlled delay elements for preconditioning and distributing closed-loop inputs and outputs, using the same control reference used by internal loop elements are also disclosed.

Abstract: A method and apparatus for outbound wave subtraction using a variable offset amplifier is described. The method includes calibration of a bi-directional signaling circuit in order to calculate one or more offset codes for cancellation of an outbound wave within a bi-directional communications link. Once the one or more offset codes are calculated, it is determined whether a dual inbound wave is received by the bi-directional signaling circuit. Once received, an offset code from the one or more calculated offset codes is selected according to a value of an outbound wave within the dual inbound/outbound wave. Finally, the outbound wave is cancelled from the dual inbound wave at an output of a variable offset amplifier using the selected offset code.

Abstract: A differential amplifier has input and output terminals to generate a second signal at the output terminals for a first signal. The amplifier has feedback switches between the output terminals and the input terminals. Offset capacitors are coupled to the differential amplifier at the input terminals and reference voltages via charging switches to provide offsets for the first signal form the reference voltages via input switches.

Abstract: In some embodiments, the invention involves a circuit including a first set of conductors to carry a current bit set and last bit set circuitry to hold and provide a last bit set. The circuit also includes drivers coupled to interconnect conductors to provide signals from the drivers to the interconnect conductors and an encoder to receive the last bit set and the current bit set and determine whether to provide the current bit set or an encoded version of the current bit set to the drivers.

Abstract: A receiver integrated circuit (IC) die or functional unit has deskew circuitry to reduce bit-to-bit timing variation that is no more than one bit time interval in a number of bits that are received, before validating the capture of the bits using a transition in a received strobe signal. The data bits and the strobe signal are driven in a parallel bus section that may be part of a shared multi-drop bus or a point-to-point bus. The system applications include interfacing to a processor or memory bus of a computer system.

Abstract: A simultaneous bidirectional port coupled to a bus combines a synchronization circuit and a data transceiver circuit. The combination data and synchronization transceiver circuit synchronizes the port with another simultaneous data port coupled to the same bus. The combination data and synchronization transceiver circuit includes a driver with a variable output impedance. Prior to synchronization, the driver has an imbalanced output impedance, and after synchronization, the driver has a substantially balanced output impedance.