Abstract: A system includes a first CML buffer configured to receive a first bias signal and a first CML signal of a first CML logic family. The first CML buffer produces a second CML signal of the first CML logic family based on the first CML signal and the first bias signal. A first coupling capacitor module couples to the first CML buffer. The first coupling capacitor module receives the second CML signal and produces a third CML signal based on the second CML signal. A second CML buffer couples to the coupling capacitor module and receives a second bias signal and the third CML signal, producing a fourth CML signal of a second CML logic family. A feedback module couples to the second CML buffer and receives the fourth CML signal producing a fifth CML signal. The second CML buffer is produces the fourth CML signal based on the second bias signal, the third CML signal, and the fifth CML signal.

Abstract: A regulated delay line device includes main regulator coupled to a node, and a plurality of delay branches coupled to the node to receive a voltage output to the node by the main regulator. Each of the plurality of delay branches includes a micro-regulator and a delay line. The delay line is coupled to the micro-regulator such that unfiltered noise is removed locally at each delay branch by a corresponding micro-regulator.

Abstract: The slew rate of signals output from an integrated circuit is selectively controlled to optimize the quality of the output data signal depending upon whether the communication channels require a faster or slower slew rate. Faster slew rates may be utilized when the communication channels are prone to attenuation, while slower slew rates may be implemented in the communication channels when crosstalk is more of a concern.

Abstract: A protection circuit with a positive field effect transistor coupled to a power source, a negative field effect transistor connected to a pass-gate and a circuit ground, a circuit input terminal, a multi-level source of protection voltage coupled to an external circuit and at least three additional field effect transistors. A drain of the negative field effect transistor couples to a gate of the positive field effect transistor. When the circuit input terminal is low the pass-gate is on; when the circuit input terminal is high the pass-gate is off. Embodiments of the invention also include stacks of three or more field effect transistors.

Abstract: Multimodal memory controllers are disclosed that include: a transmitter having a first input signal line, a second input signal line, a first output signal line, a second output signal line, a first single-ended driver, a second single-ended driver, a differential transmitter, and a mode control signal line, the mode control signal line having asserted upon it a mode control signal, the transmitter configured to operate the output signal lines using the single-ended drivers at a first voltage when the mode control signal is a first value and to operate the output signal lines using the differential transmitter at a second voltage when the mode control signal is a second value, and the transmitter configured to protect the differential transmitter from the first voltage when the mode control signal is the first value.

Abstract: A protection circuit with a positive field effect transistor coupled to a power source, a negative field effect transistor connected to a pass-gate and a circuit ground, a circuit input terminal, a multi-level source of protection voltage coupled to an external circuit and at least three additional field effect transistors. A drain of the negative field effect transistor couples to a gate of the positive field effect transistor. When the circuit input terminal is low the pass-gate is on; when the circuit input terminal is high the pass-gate is off. Embodiments of the invention also include stacks of three or more field effect transistors.

Abstract: A receiver circuit is configured as a frequency compensated differential amplifier having one input coupled to the output of a transmission line to receive a transmitted signal and the second input coupled to a reference voltage. The differential amplifier has a high frequency gain equivalent to the gain of an uncompensated differential stage for the transmitted signal. The compensated differential amplifier has an attenuated low frequency gain for signal frequencies substantially lower than the high frequency and a transitional gain for frequencies between the low and high frequencies. A compensated stage provides the portion of the signal with a compensated response and an uncompensated stage provides the portion of the amplified signal that is uncompensated. Bias control signals determine how much of the output signal is from the compensated and uncompensated stages as a means for customizing response from transmission lines with varying losses.

Abstract: Pseudo-differential drivers and receivers are used to communicate data signals between two or more IC chips. The data paths are aligned using programmable delay circuitry to de-skew each data path. A programmable reference generator is used to generate a reference voltage used by one or a group of receivers to detect the data signals. The reference voltage is adjustable using coarse as well as fine digitally controlled voltage increments. Test signals are sent from the driver to the receiver and the reference voltage is varied over its adjustable range using the coarse and fine adjustment controls while circuitry determines a measure of the detection timing jitter on successive transitions of the test signal. The operational value of the reference voltage is set to the value where the detection timing jitter is determined to be a minimum.

Abstract: A line driver for off-chip communication comprises multiple parallel stages each with separate inputs. The parallel stages each have a controlled impedance when driving the line driver output node to a logic zero or a logic one. A line driver controller is used to select what combination of driver stages are used to drive the output node based on whether the output node is transitioning between logic state or is remaining static. During power-up, a test program tries different combinations of driver stages for particular symbol patterns and determines what is the optimal ratio between line driver resistance for the dynamic and static cases and stores the optimum combination. The data stream feeding the line driver is sampled in real time to determine the transition states and selects the optimal number of driver stages for each case.

Abstract: A signal detector circuit and digital signal receiver implementing the same. In one embodiment the digital signal receiver includes a switch point detector having a detector output and including a transistor array comprising one or more pull-up branches and one or more pull-down branches. A switch point control circuit is coupled to the switch point detector. The switch point control circuit generates branch enable signals for selectively enabling or disabling said one or more pull-up branches and said one or more pull-down branches in a detector output polarity dependent manner.

Abstract: Pseudo-differential drivers and receivers are used to communicate data signals between two or more IC chips. The data paths are aligned using programmable delay circuitry to de-skew each data path. A programmable reference generator is used to generate a reference voltage used by one or a group of receivers to detect the data signals. The reference voltage is adjustable using coarse as well as fine digitally controlled voltage increments. Test signals are sent from the driver to the receiver and the reference voltage is varied over its adjustable range using the coarse and fine adjustment controls while circuitry determines a measure of the detection timing jitter on successive transitions of the test signal. The operational value of the reference voltage is set to the value where the detection timing jitter is determined to be a minimum.

Abstract: A line driver for off-chip communication comprises multiple parallel stages each with separate inputs. The parallel stages each have a controlled impedance when driving the line driver output node to a logic zero or a logic one. A line driver controller is used to select what combination of driver stages are used to drive the output node based on whether the output node is transitioning between logic state or is remaining static. During power-up, a test program tries different combinations of driver stages for particular symbol patterns and determines what is the optimal ratio between line driver resistance for the dynamic and static cases and stores the optimum combination. The data stream feeding the line driver is sampled in real time to determine the transition states and selects the optimal number of driver stages for each case.

Abstract: A receiver circuit is configured as a frequency compensated differential amplifier having one input coupled to the output of a transmission line to receive a transmitted signal and the second input coupled to a reference voltage. The differential amplifier has a high frequency gain equivalent to the gain of an uncompensated differential stage for the transmitted signal. The compensated differential amplifier has an attenuated low frequency gain for signal frequencies substantially lower than the high frequency and a transitional gain for frequencies between the low and high frequencies. A compensated stage provides the portion of the signal with a compensated response and an uncompensated stage provides the portion of the amplified signal that is uncompensated. Bias control signals determine how much of the output signal is from the compensated and uncompensated stages as a means for customizing response from transmission lines with varying losses.

Abstract: The slew rate of signals output from an integrated circuit is selectively controlled to optimize the quality of the output data signal depending upon whether the communication channels require a faster or slower slew rate. Faster slew rates may be utilized when the communication channels are prone to attenuation, while slower slew rates may be implemented in the communication channels when crosstalk is more of a concern.

Abstract: Data signals are transmitted over transmission lines in groups to receivers in a receiving IC. Each group of data signals has a differential clock used in synchronizing and detecting the data signals. The data signal eye windows vary with timing jitter in the data signals relative to the clock edges and the asymmetry in a compensated clock signal detected from the differential clock using a duty cycle adjustment circuit. Error detection determines if the clock asymmetry is affecting the eye window of the data signals. Control signals selectively adjust the gain of differential stages generating the compensated clock to modify the duty cycle of the compensated clock. The eye window of the data signals are monitored and used as feedback to servo the control signals to optimize the duty cycle of the compensated clock signal for sampling the data signals.

Abstract: A signal detector circuit and digital signal receiver implementing the same. In one embodiment the digital signal receiver includes a switch point detector having a detector output and including a transistor array comprising one or more pull-up branches and one or more pull-down branches. A switch point control circuit is coupled to the switch point detector. The switch point control circuit generates branch enable signals for selectively enabling or disabling said one or more pull-up branches and said one or more pull-down branches in a detector output polarity dependent manner.