Abstract: A circuit for driving digital-to-analog converter (DAC) comprising a serializer configured to combine multiple signals to one input signal to drive a forward inverter coupled to a first node with a first impedance in serial configuration and a first capacitance in shunt configuration. The circuit includes a chain of inverters coupled in series to transfer the input signal from the first node to the fifth node based on a signal transfer function. The circuit further includes a feedback inverter between the third node and the first node to form a feedback loop with two inverters in the chain, adding peaking in the signal transfer function at the first node. A second feedback inverter can be added between the fifth node and the third node to add peaking in the signal transfer function at the third node. The feedback inverter is designed as a current-starved inverter in order to alleviate hot-carrier injection (HCI) aging of the transistors and add programmability in the peaking.

Abstract: An apparatus for multiphase clock calibration for a transmitter in data communication systems includes a phase interpolator (PI) configured to receive a clock signal and generate multiphase clock signals with adjustable duty cycles and in-phase quadrature control. The apparatus may include a pattern generator coupled to the PI and configured to generate a pattern output based on a data signal sampled by the multiphase clock signals. The apparatus also includes a delay-adjust module coupled to the PI and configured to measure timing differences between the edges of a reference clock and the pattern output with adjustable delays. A phase detector is coupled to the pattern generator and configured to detect a phase error between the pattern output and the reference clock. A calibration controller is configured to provide controls to the PI and the delay-adjust module for adjusting delays to the reference clock and the pattern output to calibrate the multiphase clock signals.

Abstract: An apparatus for multiphase clock calibration for a transmitter in data communication systems includes a phase interpolator (PI) configured to receive a clock signal and generate multiphase clock signals with adjustable duty cycles and in-phase quadrature control. The apparatus may include a pattern generator coupled to the PI and configured to generate a pattern output based on a data signal sampled by the multiphase clock signals. The apparatus also includes a delay-adjust module coupled to the PI and configured to measure timing differences between the edges of a reference clock and the pattern output with adjustable delays. A phase detector is coupled to the pattern generator and configured to detect a phase error between the pattern output and the reference clock. A calibration controller is configured to provide controls to the PI and the delay-adjust module for adjusting delays to the reference clock and the pattern output to calibrate the multiphase clock signals.

Abstract: A circuit for driving digital-to-analog converter (DAC) comprising a serializer configured to combine multiple signals to one input signal to drive a forward inverter coupled to a first node with a first impedance in serial configuration and a first capacitance in shunt configuration. The circuit includes a chain of inverters coupled in series to transfer the input signal from the first node to the fifth node based on a signal transfer function. The circuit further includes a feedback inverter between the third node and the first node to form a feedback loop with two inverters in the chain, adding peaking in the signal transfer function at the first node. A second feedback inverter can be added between the fifth node and the third node to add peaking in the signal transfer function at the third node. The feedback inverter is designed as a current-starved inverter in order to alleviate hot-carrier injection (HCI) aging of the transistors and add programmability in the peaking.

Abstract: An example transmitter includes: an output comprising a first terminal and a second terminal; a driver having first transistor switches coupled to first current sources; a first circuit having a first transistor coupled between the first transistor switches and the first terminal, and a second transistor coupled between the first transistor switches and the second terminal; and a second circuit, coupled between the output and gates of the first and second transistors, configured to bias the first transistor with a first fraction of a first voltage signal at the first terminal and bias the second transistor with a first fraction of a second voltage signal at the second terminal.

Abstract: A circuit for driving digital-to-analog converter (DAC) comprising a serializer configured to combine multiple signals to one input signal to drive a forward inverter coupled to a first node with a first impedance in serial configuration and a first capacitance in shunt configuration. The circuit includes a chain of inverters coupled in series to transfer the input signal from the first node to the fifth node based on a signal transfer function. The circuit further includes a feedback inverter between the third node and the first node to form a feedback loop with two inverters in the chain, adding peaking in the signal transfer function at the first node. A second feedback inverter can be added between the fifth node and the third node to add peaking in the signal transfer function at the third node. The feedback inverter is designed as a current-starved inverter in order to alleviate hot-carrier injection (HCI) aging of the transistors and add programmability in the peaking.

Abstract: Disclosed herein are related to systems and methods for providing different power supply levels. In one aspect, a first circuit generates a first signal having a first amplitude according to a first supply voltage. A latch may be coupled to a resistor of a plurality of resistors coupled in series. One end of the resistor may be configured to provide to the latch a second supply voltage higher than the first supply voltage according to a third supply voltage higher than the second supply voltage, and another end of the resistor may be configured to receive the third supply voltage. The latch may modify the first signal to provide a second signal, according to the second supply voltage. An amplifier may amplify the second signal to provide a third signal having a second amplitude larger than the first amplitude, according to the third supply voltage.

Abstract: Disclosed herein are related to a system and a method for high speed communication. In one aspect, the system includes a set of slicers configured to generate a slicer output signal digitally indicating a level of an input signal received by the set of slicers. The system includes a speculative tap coupled to the set of slicers, where the speculative tap is configured to select bits of the slicer output signal based on selected bits of a prior slicer output signal. The system includes a decoder coupled to the speculative tap, where the decoder is configured to decode the selected bits of the slicer output signal in a first digital representation into a second digital representation. The system includes a feedback generator coupled to the decoder, where the feedback generator is configured to generate a feedback signal according to the decoded bits of the slicer output signal.

Abstract: Disclosed herein are related to a system and a method for high speed communication. In one aspect, the system includes a set of slicers configured to generate a slicer output signal digitally indicating a level of an input signal received by the set of slicers. The system includes a speculative tap coupled to the set of slicers, where the speculative tap is configured to select bits of the slicer output signal based on selected bits of a prior slicer output signal. The system includes a decoder coupled to the speculative tap, where the decoder is configured to decode the selected bits of the slicer output signal in a first digital representation into a second digital representation. The system includes a feedback generator coupled to the decoder, where the feedback generator is configured to generate a feedback signal according to the decoded bits of the slicer output signal.

Abstract: Disclosed herein are related to a system and a method for high speed communication. In one aspect, the system includes a set of slicers configured to generate a slicer output signal digitally indicating a level of an input signal received by the set of slicers. The system includes a speculative tap coupled to the set of slicers, where the speculative tap is configured to select bits of the slicer output signal based on selected bits of a prior slicer output signal. The system includes a decoder coupled to the speculative tap, where the decoder is configured to decode the selected bits of the slicer output signal in a first digital representation into a second digital representation. The system includes a feedback generator coupled to the decoder, where the feedback generator is configured to generate a feedback signal according to the decoded bits of the slicer output signal.

Abstract: A keeper based switch driver can generate overlapping differential signals and increase a crossing point of the overlapping differential signals a first predetermined amount. Additionally, the keeper based switch driver can further increase the crossing point of the overlapping differential signals a second predetermined amount and limit signal swing to an absolute value of a drain-source voltage. A microprocessor can also be electrically connected to a DAC cell with keeper based switch driver through a performance detection circuit. The microprocessor can be configured to receive information from a performance detection circuit and control a current of a variable current source in a keeper bias circuit accordingly.

Abstract: A keeper based switch driver can generate overlapping differential signals and increase a crossing point of the overlapping differential signals a first predetermined amount. Additionally, the keeper based switch driver can further increase the crossing point of the overlapping differential signals a second predetermined amount and limit signal swing to an absolute value of a drain-source voltage. A microprocessor can also be electrically connected to a DAC cell with keeper based switch driver through a performance detection circuit. The microprocessor can be configured to receive information from a performance detection circuit and control a current of a variable current source in a keeper bias circuit accordingly.