Abstract: Integrated circuits with clock generation and distribution circuitry are provided. Integrated circuits may include phase-locked loops configured to generate multiple clock signals that are delayed versions of one another. The clocks signal may be distributed to various regions on an integrated circuit using serially connected clock buffer blocks. Each buffer block may include bidirectional pairs of buffer circuits coupled in parallel. Each buffer circuit may have a first input configured to receive an input clock signal, an output at which a corrected version of the input clock signal is provided (e.g., an output at which an output clock signal with desired duty cycle is provided), a second input that receives a first delayed clock signal for setting the desired duty cycle for the output clock signal, and a third input that receives a second delayed clock signal that is high at least when the first delayed clock signal rises high.

Abstract: Integrated circuits with memory circuitry are provided. The memory circuitry may include rows of data line segments. Each data line segment may have associated memory cells, a programmable-strength precharge circuit, a latch circuit, a programmable-strength pull-up circuit, and a data line segment buffer. The precharge circuit may include multiple paths that can be switched into use depending on the configuration of programmable bits. The programmable-strength pull-up circuit may include multiple pull-up paths. The number of pull-up paths in use can be configured. The latch circuit may include a latch inverter that enables the programmable latch circuit during precharge operations. During a precharge period, the latch circuit can be disabled to block contending pull-down current and the data line segment buffer can be disabled to avoid crossbar currents.

Abstract: Integrated circuits with clock generation and distribution circuitry are provided. Integrated circuits may include phase-locked loops configured to generate multiple clock signals that are delayed versions of one another. The clocks signal may be distributed to various regions on an integrated circuit using serially connected clock buffer blocks. Each buffer block may include bidirectional pairs of buffer circuits coupled in parallel. Each buffer circuit may have a first input configured to receive an input clock signal, an output at which a corrected version of the input clock signal is provided (e.g., an output at which an output clock signal with desired duty cycle is provided), a second input that receives a first delayed clock signal for setting the desired duty cycle for the output clock signal, and a third input that receives a second delayed clock signal that is high at least when the first delayed clock signal rises high.

Abstract: Integrated circuits with clock generation and distribution circuitry are provided. Integrated circuits may include phase-locked loops configured to generate multiple clock signals that are delayed versions of one another. The clocks signal may be distributed to various regions on an integrated circuit using serially connected clock buffer blocks. Each buffer block may include bidirectional pairs of buffer circuits coupled in parallel. Each buffer circuit may have a first input configured to receive an input clock signal, an output at which a corrected version of the input clock signal is provided (e.g., an output at which an output clock signal with desired duty cycle is provided), a second input that receives a first delayed clock signal for setting the desired duty cycle for the output clock signal, and a third input that receives a second delayed clock signal that is high at least when the first delayed clock signal rises high.

Abstract: Integrated circuits with clock generation and distribution circuitry are provided. Integrated circuits may include phase-locked loops configured to generate multiple clock signals that are delayed versions of one another. The clocks signal may be distributed to various regions on an integrated circuit using serially connected clock buffer blocks. Each buffer block may include bidirectional pairs of buffer circuits coupled in parallel. Each buffer circuit may have a first input configured to receive an input clock signal, an output at which a corrected version of the input clock signal is provided (e.g., an output at which an output clock signal with desired duty cycle is provided), a second input that receives a first delayed clock signal for setting the desired duty cycle for the output clock signal, and a third input that receives a second delayed clock signal that is high at least when the first delayed clock signal rises high.

Abstract: An adjustable delay circuit includes first and second transistors each having a control input coupled to an input node of the adjustable delay circuit and an output coupled to an output node of the adjustable delay circuit. The adjustable delay circuit includes a first pass gate coupled between first and second capacitors and the output node of the adjustable delay circuit. The first and the second capacitors are coupled between a node at a high voltage and a node at a low voltage. The first pass gate is operable to be controlled by a first delay control signal.

Abstract: A dynamic phase alignment circuit includes a phase generator circuit having delay-locked loop circuits that generate periodic output signals. Each of the delay-locked loop circuits generates one of the periodic output signals in response to at least two periodic input signals. A multiplexer circuit selects a selected periodic signal from among the periodic input signals and the periodic output signals based on select signals. A phase detection circuit compares a phase of the selected periodic signal to a data signal to generate a phase detection signal. A control logic circuit generates the select signals. The control logic circuit adjusts the select signals based on changes in the phase detection signal to cause the multiplexer circuit to adjust the phase of the selected periodic signal.

Abstract: A circuit includes first transistors and a comparator. The comparator compares a reference signal and a signal that is based on conductive states of the first transistors. A control circuit generates first control signals based on an output signal of the comparator. The conductive states of the first transistors are determined based on the first control signals. An arithmetic circuit performs an arithmetic function based on the first control signals and second control signals to generate calibration signals. Second transistors provide a termination impedance at an external terminal of the circuit that is based on the calibration signals.

Abstract: Integrated circuits with memory elements are provided. The memory elements may be arranged in an array. Data lines may be used to load data into the memory elements and may be used to read data from the memory elements. The memory elements may be used to store configuration data on a programmable logic device integrated circuit. Each memory element may have an output that supplies a programmable transistor gate with a static control signal. Data reading circuitry may be coupled to each data line to read data from an addressed memory element on that data line. The data reading circuitry for each data line may include a precharge transistor and an output latch. The output latch may contain cross-coupled inverters. An inwardly-directed inverter in the output latch may have a pull-up transistor that is connected in series with a current source.

Abstract: Circuits may provide series on-chip termination impedance to one or more input/output pins. In one embodiment, two off-chip reference resistors in combination with internal calibration circuitry are used to control termination transistors coupled to several input/output (I/O) pins. The termination transistors behave as programmably adjustable termination resistors that match the impedance of external resistors. By using only a small number of reference resistors (e.g., 2 resistors) for a large number of I/O pins, the present invention eliminates the external components that would otherwise be needed to provide resistance termination. The effective series termination resistance may be programmed, enabling the termination resistance to meet different I/O standards. Further, the resistance termination techniques of the present invention are not sensitive to process, voltage supply, and temperature (PVT) variations.

Abstract: Circuits that have programmable parallel on-chip termination impedance are provided. On-chip transistors provide parallel termination impedance to an I/O pin. The impedance of the on-chip transistors can be programmed by an impedance matching circuit in response to the value of external resistors. The impedance matching circuit can regulate the impedance of termination transistors that are coupled to numerous I/O pins on an integrated circuit. This technique eliminates the need for external resistors that provide parallel termination impedance to I/O pins.

Abstract: An output buffer having one or more of the following advantages: (1) faster slew rate, (2) reduced switching noise during signal transitions, and (3) improved switching time. The output buffer includes a pair of output transistors. At least one of the output transistors is designed with dynamically adjustable beta that allows for robust control of the output buffer operating characteristics. The beta can be adjusted by changing the size of the output transistor. Transistor size can be changed, in turn, by enabling and disabling additional output transistor(s).

Abstract: A novel logic input buffer having independent DC input trip points (e.g., V.sub.IL and V.sub.IH), reduced cross current during signal transitions, shorter propagation delay, and improved noise performance. The input buffer includes a set of input transistors having dynamically adjustable beta(s) that allows for robust control of the transistor(s) operating characteristics. The beta(s) can be adjusted by changing the size(s) of the input transistors through enabling and disabling selected one(s) of additional input transistor(s).

Abstract: A sense amplifier for detecting a logic state of a memory cell includes a voltage amplifier, a current mirror, and a feedback circuit. The voltage amplifier couples to the memory cell and the current mirror. The feedback circuit couples to the current mirror and an input of the sense amplifier. The feedback circuit can be implemented with a transistor, a switch, a transmission gate, or the like. The feedback circuit is selectively enabled to quickly charge or discharge the voltage at the input of the sense amplifier to a trip voltage of the sense amplifier. Whether charging or discharging is performed is dependent on the voltage then existing at the input node. The amount of charging and discharging current can also be based on other circuit considerations, such as the required charge time, and so on. When the voltage at the input reaches a predetermined voltage range, the feedback circuit is disabled.