Abstract: Provided is a method and system for controlling current characteristics in a transceiver having a transmitter. The method includes identifying a phase control signal from an adjacent current cell preceding the particular current cell in time and logically ORing the phase control signal from the preceding cell with a phase control signal from the particular current cell.

Abstract: A power efficient and reduced electromagnetic interference (EMI) emissions transmitter for unshielded twisted pair (UTP) data communication applications. Transmit data is processed by a digital filter. The digital filter output data is converted to a current-mode analog waveform by a digital-to-analog converter (DAC). The digital filter is integrated with the DAC binary decoder in a memory device such as a ROM with time multiplexed output. DAC line driver cells are adaptively configurable to operate in either a class-A or a class-B mode depending on the desired operational modality. A discrete-time analog filter is integrated with the DAC line driver to provide additional EMI emissions suppression. An adaptive electronic transmission signal cancellation circuit separates transmit data from receive data in a bidirectional communication system operating in full duplex mode.

Abstract: A communication system includes an integrated circuit (IC) die having an on-chip source termination. The on-chip source termination can be a non-precision resistor, such as an unsilicided poly resistor, or any other suitable termination. As compared to an off-chip source termination, the on-chip source termination can reduce voltage peaking and/or voltage overshoot in the IC die and/or at a load that is connected to the IC die. The IC die can further include a line driver to provide a source current. A bias generator can be included to provide a bias current to the line driver. The bias generator can include a first current source coupled to an off-chip resistor and a second current source coupled to an on-chip resistor. An output voltage of the IC die can be adjusted by manipulating a trim control of the off-chip resistor and/or a trim control of the on-chip resistor.

Abstract: A physical layer device (PLD) includes a first serializer-deserializer (SERDES) device and a second SERDES device. Each SERDES device includes an analog portion with a serial port that is configured to communicate serial data with various network devices, and a digital portion that is configured to communicate parallel data with other various network devices. The PLD includes a first signal path that is configured to route serial data signals between the analog portions of the SERDES devices, bypassing the digital portions of the SERDES devices. Therefore, the SERDES devices can directly communicate serial data without performing parallel data conversion. A second signal path is configured to route recovered clock and data signals between the analog portions of the SERDES devices, but still bypassing the digital portions of the SERDES devices. The recovered clock and data signals are then regenerated before being transmitted over a network device.

Abstract: A reduced emission transmitter may comprise an encoder partitioned into at least a group of odd encoder processing cells and a group of even encoder processing cells. A DAC may be partitioned into at least: a group of odd DAC processing cells for processing outputs of the group of odd encoder processing cells, and a group of even DAC processing cells for processing outputs of the group of even encoder processing cells. The reduced emission transmitter may further comprise an aggregator that aggregates the outputs of the odd DAC processing cells and the outputs of the even DAC processing cells to generate a reduced emissions analog DAC output. At least one clock generator is provided, which generates a first clock signal and a second clock signals that clocks the even encoder processing cells, and the odd encoder processing cells respectively. The second clock signal is a delayed version of the first clock signal.

Abstract: A power efficient and reduced electromagnetic interference (EMI) emissions transmitter for unshielded twisted pair (UTP) data communication applications. Transmit data is processed by a digital filter. The digital filter output data is converted to a current-mode analog waveform by a digital-to-analog converter (DAC). The digital filter is integrated with the DAC binaiy decoder in a memory device such as a ROM with time multiplexed output. DAC line driver cells are adaptively configurable to operate in either a class-A or class-B mode depending on the desired operational modality. A discrete-time analog filter is integrated with the DAC line driver to provide additional EMI emissions suppression. An adaptive electronic transmission signal cancellation circuit separates transmit data from receive data in a bidirectional communication system operating in full duplex mode.

Abstract: A communication system includes an integrated circuit (IC) die having an on-chip source termination. The on-chip source termination can be a non-precision resistor, such as an unsilicided poly resistor, or any other suitable termination. As compared to an off-chip source termination, the on-chip source termination can reduce voltage peaking and/or voltage overshoot in the IC die and/or at a load that is connected to the IC die. The IC die can further include a line driver to provide a source current. A bias generator can be included to provide a bias current to the line driver. The bias generator can include a first current source coupled to an off-chip resistor and a second current source coupled to an on-chip resistor. An output voltage of the IC die can be adjusted by manipulating a trim control of the off-chip resistor and/or a trim control of the on-chip resistor.

Abstract: A power efficient and reduced electromagnetic interference (EMI) emissions multi-transmitter system for unshielded twisted pair (UTP) data communication applications. For each transmitter, digital transmit data is converted to a current-mode differential signal analog waveform by a digital-to-analog converter (DAC). The output current from each DAC is used to generate the required transmit voltage on the respective UTP line. Timing circuitry staggers the time base of each transmitter to reduce the aggregate EMI emissions of the multi-transmitter system.

Abstract: An adaptive electronic transmission signal cancellation circuit for separating transmit data from receive data in a bidirectional communication system operating in full duplex mode is disclosed. The output of a main transmitter responsive to a first bias current is connected to the output of a receiver through an internal resistor. A first replica transmitter responsive to a second bias current and matched to the main transmitter current gain and rise/fall time characteristics is connected to the input terminal of the receiver, and produces a cancellation voltage between the output terminal of the main transmitter and the input terminal of the receiver as a function of the second bias current and the internal resistor.

Abstract: A power efficient and reduced electromagnetic interference (EMI) emissions transmitter for unshielded twisted pair (UTP) data communication applications. Transmit data is processed by a digital filter. The digital filter output data is converted to a current-mode analog waveform by a digital-to-analog converter (DAC). The digital filter is integrated with the DAC binary decoder in a memory device such as a ROM with time multiplexed output. DAC line driver cells are adaptively configurable to operate in either a class-A or class-B mode depending on the desired operational modality. A discrete-time analog filter is integrated with the DAC line driver to provide additional EMI emissions suppression. An adaptive electronic transmission signal cancellation circuit separates transmit data from receive data in a bidirectional communication system operating in full duplex mode.

Abstract: A programable gain amplifier (PGA) has an amplifier and a variable resistor that is connected to the output of the amplifier. The variable resistor includes a resistor that is connected to a reference voltage and multiple parallel taps that tap off the resistor. A two-stage switch network having fine stage switches and coarse stage switches connects the resistor taps to an output node of the PGA. The taps and corresponding fine stage switches are arranged into two or more groups, where each group has n-number of fine stage switches and corresponding taps. One terminal of each fine stage switch is connected to the corresponding resistor tap, and the other terminal is connected to an output terminal for the corresponding group. The coarse stage switches select from among the groups of fine stage switches, and connect to the output of the PGA.

Abstract: A power efficient and reduced electromagnetic interference (EMI) emissions transmitter for unshielded twisted pair (UTP) data communication applications. Transmit data is interpolated by N and processed by a digital filter to obtain the pulse shape required by the particular communication application. The digital filter output data is converted to a current-mode analog waveform by a digital-to-analog converter (DAC). The digital filter is integrated with the DAC binary decoder in a memory device such as a ROM with time multiplexed output. When implemented in such manner, the logical implementation and memory replaces digital filtering circuits, DAC decoding logic circuit and re-synchronization logic circuits that are conventionally implemented in hardware. Thus, the hardware functionality of these circuits is rendered into arithmetic form and implemented in a memory device.

Abstract: A power efficient and reduced electromagnetic interference (EMI) emissions multi-transmitter system for unshielded twisted pair (UTP) data communication applications. For each transmitter, digital transmit data is converted to a current-mode differential signal analog waveform by a digital-to-analog converter (DAC). The output current from each DAC is used to generate the required transmit voltage on the respective UTP line. Timing circuitry staggers the time base of each transmitter to reduce the aggregate EMI emissions of the multi-transmitter system.

Abstract: A reduced emission transmitter may include an encoder block, which may be partitioned into a first group comprising odd encoder processing cells and a second group comprising even encoder processing cells. A DAC block may also be partitioned into a first group comprising odd DAC processing cells and a second group comprising even DAC processing cells. The first group of encoder processing cells may be coupled to the first group of DAC processing cells and the second group of encoder processing cells may be coupled to the second group of DAC processing cells. The first group of encoder processing cells may be clocked using a first clock signal and the second group of encoder processing cells may be clocked using a second clock signal, the second clock signal being a delayed version of the first clock signal.

Abstract: A programable gain amplifier (PGA) has an amplifier and a variable resistor that is connected to the output of the amplifier. The variable resistor includes a resistor that is connected to a reference voltage and multiple parallel taps that tap off the resistor. A two-stage switch network having fine stage switches and coarse stage switches connects the resistor taps to an output node of the PGA. The taps and corresponding fine stage switches are arranged into two or more groups, where each group has n-number of fine stage switches and corresponding taps. One terminal of each fine stage switch is connected to the corresponding resistor tap, and the other terminal is connected to an output terminal for the corresponding group. The coarse stage switches select from among the groups of fine stage switches, and connect to the output of the PGA.

Abstract: A line driver selectively drives one of two transmission lines. The line driver includes a differential amplifier connected to first and second differential switches. The first differential switch is connected between an output of the differential amplifier and a first of two transmission lines. The second differential switch is connected to the output of the differential amplifier and to the second of two transmission lines. The first and second differential switches are controlled by respective first and second control signals. The output of the differential amplifier is connected to either the first or the second transmission line in response to the first and second control signals. The differential switches include loopback protection to an prevent an incoming signal from passing from one transmission line to another during power down mode.

Abstract: A power efficient and reduced electromagnetic interference (EMI) emissions multi-transmitter system for unshielded twisted pair (UTP) data communication applications. For each transmitter, digital transmit data is converted to a current-mode differential signal analog waveform by a digital-to-analog converter (DAC). The output current from each DAC is used to generate the required transmit voltage on the respective UTP line. Timing circuitry staggers the time base of each transmitter to reduce the aggregate EMI emissions of the multi-transmitter system.

Abstract: A power efficient and reduced electromagnetic interference (EMI) emissions transmitter for unshielded twisted pair (UTP) data communication applications. Transmit data is processed by a digital filter. The digital filter output data is converted to a current-mode analog waveform by a digital-to-analog converter (DAC). The digital filter is integrated with the DAC binary decoder in a memory device such as a ROM with time multiplexed output. DAC line driver cells are adaptively configurable to operate in either a class-A or a class-B mode depending on the desired operational modality. A discrete-time analog filter is integrated with the DAC line driver to provide additional EMI emissions suppression. An adaptive electronic transmission signal cancellation circuit separates transmit data from receive data in a bidirectional communication system operating in full duplex mode.

Abstract: An adaptive electronic transmission signal cancellation circuit for separating transmit data from receive data in a bidirectional communication system operating in full duplex mode is disclosed. The output of a main transmitter responsive to a first bias current is connected to the output of a receiver through an internal resistor. A first replica transmitter responsive to a second bias current and matched to the main transmitter current gain and rise/fall time characteristics is connected to the input terminal of the receiver, and produces a cancellation voltage between the output terminal of the main transmitter and the input terminal of the receiver as a function of the second bias current and the internal resistor.

Abstract: A line driver selectively drives one of two transmission lines. The line driver includes a differential amplifier connected to first and second differential switches. The first differential switch is connected between an output of the differential amplifier and a first of two transmission lines. The second differential switch is connected to the output of the differential amplifier and to the second of two transmission lines. The first and second differential switches are controlled by respective first and second control signals. The output of the differential amplifier is connected to either the first or the second transmission line in response to the first and second control signals. The differential switches include loopback protection to an prevent an incoming signal from passing from one transmission line to another during power down mode.