Abstract: An amplifier includes multiple stages. Early stages of the multi-stage amplifier have low gain and preserve bandwidth.

Abstract: A phase lock loop circuit including a voltage controlled oscillator and a phase detector having a sampling circuit and a linear voltage-to-current converter to create a control voltage for the voltage controlled oscillator. The phase lock loop circuit comprising a voltage-to-current circuit to influence a voltage on a capacitor, the voltage controlled oscillator responsive to the voltage on the capacitor, and the sampling circuit responsive to the first and second clock signals to generate two voltage values.

Abstract: A simultaneous bidirectional port coupled to a bus combines a synchronization circuit and a clock circuit. The synchronization and clock circuit synchronizes the port with another simultaneous data port coupled to the same bus. A clock driver circuit is provided that is capable of being turned on and off. Prior to synchronization, the clock driver is off, and after synchronization, the clock driver is on. A clock receiver circuit includes a clock detection circuit to detect the presence of an input clock signal. When an integrated circuit is ready to communicate, the output clock driver is turned on and the clock detection circuit is monitored to determine when an input clock signal is received. When both the output clock driver is turned on, and an input clock signal is being received, the simultaneous bidirectional port is synchronized, and communication between integrated circuits can take place.

Abstract: A low jitter external clocking system and method are disclosed. According to one embodiment of the present invention, a differential clock signal is received on a first clock signal line and a second clock signal line. A differential amplifier coupled to the first clock signal line and the second clock signal line amplifies the differential clock signal into a single-ended output clock signal.

Abstract: A discrete-time analog filter, where a filter tap of the filter comprises a voltage-to-current converter, an active current mirror, and a current multiplier to provide a current signal indicative of a weighted sampled voltage signal. The current signals from the filter taps 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. The voltage-to-current converter may include a common-mode high-pass filter to reject common-mode voltage variations.

Abstract: A simultaneous bidirectional port coupled to a bus combines a synchronization circuit and a clock circuit. The synchronization and clock circuit synchronizes the port with another simultaneous data port coupled to the same bus. A clock driver circuit is provided that is capable of being turned on and off. Prior to synchronization, the clock driver is off, and after synchronization, the clock driver is on. A clock receiver circuit includes a clock detection circuit to detect the presence of an input clock signal. When an integrated circuit is ready to communicate, the output clock driver is turned on and the clock detection circuit is monitored to determine when an input clock signal is received. When both the output clock driver is turned on, and an input clock signal is being received, the simultaneous bidirectional port is synchronized, and communication between integrated circuits can take place.

Abstract: A variety of embodiments may include a voltage controlled oscillator to generate a differential signal on two nodes; and phase detector to compare a phase of the differential signal and a phase of a received signal, the phase detector including a sampling circuit to periodically sample voltage values on the two nodes, and a linear voltage-to-current converter responsive to the voltage values to create a control voltage for the voltage controlled oscillator.

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 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 disclosed.

Abstract: An integrated circuit compensates for power supply voltage dependent delay using a clock circuit that is responsive to a power supply voltage measuring circuit. The clock circuit modifies a phase relationship based on a measured power supply voltage value.

Abstract: According to some embodiments, a circuit provides a first set of one or more flip-flops to receive a low-swing differential clock, and a second set of one or more flip-flops to receive the low-swing differential clock. One of the one or more flip-flops of the first set is to generate a first CMOS-level sampling pulse for each cycle of the low-swing differential clock, and wherein one of the one or more flip-flops of the second set is to generate a second CMOS-level sampling pulse for each cycle of the low-swing differential clock.

Abstract: In some embodiments, the invention involves multiple integrated circuit stubs coupled in series. At least one of the integrated circuit stubs including first conductors to receive signals from a first adjacent one of the integrated circuit stubs, second conductors to provide signals to a second adjacent one of the integrated circuit stubs, and third conductors to provide signals to an integrated circuit chip. The integrated circuit stubs include first drivers and second drivers coupled to the first, second, and third conductors, wherein the first drivers receive the external signals from the first conductors and drive them onto the second conductors and the second drivers receive signals from the first conductors and drive them onto the third conductors.

Abstract: According to some embodiments, a circuit provides a first set of one or more flip-flops to receive a low-swing differential clock, and a second set of one or more flip-flops to receive the low-swing differential clock. One of the one or more flip-flops of the first set is to generate a first CMOS-level sampling pulse for each cycle of the low-swing differential clock, and wherein one of the one or more flip-flops of the second set is to generate a second CMOS-level sampling pulse for each cycle of the low-swing differential clock.

Abstract: A bi-directional communication system includes a driver capable of controlling a slew rate of transmitted data signals. Impedance matching can be provided to match an impedance of a driver circuit to an impedance of a communication line. The impedance is maintained constant as data is driven from the data driver. The data receiver circuit can adjust a reference voltage in response to simultaneously transmitted data. The slew rate of the receiver circuit trip point is controlled to maintain adequate noise margin during operation. Both the receiver and driver circuits can be controlled using a delay line circuit.

Abstract: A synchronous clock generator for an integrated circuit is described in which a delay lock loop circuit may be used to delay a first input signal. A delay circuit is coupled to the delay lock loop circuit and receives a control voltage from the delay lock loop circuit, which is used to delay a second input signal. The first and second input signal may be complimentary.

Abstract: A simultaneous bidirectional port coupled to a bus combines a synchronization circuit and a clock circuit. The synchronization and clock circuit synchronizes the port with another simultaneous data port coupled to the same bus. A clock driver circuit is provided that is capable of being turned on and off. Prior to synchronization, the clock driver is off, and after synchronization, the clock driver is on. A clock receiver circuit includes a clock detection circuit to detect the presence of an input clock signal. When an integrated circuit is ready to communicate, the output clock driver is turned on and the clock detection circuit is monitored to determine when an input clock signal is received. When both the output clock driver is turned on, and an input clock signal is being received, the simultaneous bidirectional port is synchronized, and communication between integrated circuits can take place.

Abstract: A signal propagation system includes a plurality of memory modules that receive a clock signal from a system clock generator. A backplane has a first clock line that propagates a clock signal from the generator to a first memory module of the plurality of memory modules. The backplane may also include a second line that propagates a clock signal between the first and a second memory module of the plurality. The first memory module may include an onboard transmission line that propagates a clock signal between respective first and second clock lines of the backplane.

Abstract: A discrete-time analog filter, where a filter tap of the filter comprises a voltage-to-current converter, an active current mirror, and a current multiplier to provide a current signal indicative of a weighted sampled voltage signal. The current signals from the filter taps 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. The voltage-to-current converter may include a common-mode high-pass filter to reject common-mode voltage variations.

Abstract: A system and method for encoding and receiving data is provided. The data is encoded as a pulse amplitude modulated signal such that the amplitude signals do not transition from the highest signal level to the lowest signal level and do not transition from the lowest signal level to the highest signal level. The encoding and decoding is performed in some embodiments via a lookup table, and in further embodiments is designed to minimize the step between sequential pulse amplitude modulated symbols.

Abstract: A data receiver circuit having a comparator that exhibits substantially variable offset that is controllable to represent a variable reference level, without a separate input to receive a reference voltage level. The comparator output provides an indication of the comparison between a fixed voltage level applied to its differential signal input and the variable reference level. While changing an offset code that is fed to an offset control input of the comparator, and while applying a fixed voltage level that represents a symbol in the transmission line analog signal, a value of the offset code which causes the output of the comparator to change states is captured. A similar process may be repeated for different symbol values that can be transmitted, such that an indication of the voltage margin may be obtained as a difference between two captured offset codes. Circuitry to perform the process may be provided on-chip to the receiver circuit.