Abstract: A clock recovery circuit uses a pair of variable delay lines to recover clock from a non-return to zero (NRZ) data stream. If an incoming clock transition occurs in the NRZ data, it is passed through one delay line to the output. If no incoming transition occurs, the transition at the output of the first delay line is recycled back through the second delay line. The outputs of the first and second delay lines are combined so that a transition occurs at every possible transition instant, regardless of whether a transition is present in the incoming data at the corresponding time. This permits the benefits of a delay locked loop to be achieved when using NRZ data. Applications of the clock recovery circuits to gigabit data communications systems are describe.

Abstract: A frequency difference detector includes a pulse generator that receives an NRZ signal and a reference signal and provides data pulses having first edges based on edges of the NRZ signal and second edges based on edges of the reference signal, a pulse router that routes consecutive ones of the data pulses to different signal paths, a voltage generator that receives the data pulses from the signal paths and provides voltage signals with amplitudes based on pulse widths of the data pulses, and a comparison circuit that receives the voltage signals and provides error pulses with amplitudes based on voltage differences between the voltage signals. The amplitudes of the error pulses represent a frequency difference between the NRZ signal and the reference signal. Preferably, the data pulses have leading edges based on edges of the NRZ signal and the lagging edges based on leading edges of the reference signal immediately following the edges of the NRZ signal.

Abstract: A microprocessor includes an on-chip low phase noise CMOS LC capacitance oscillator. The LC oscillator is relatively insensitive to power supply fluctuations. In addition, the LC oscillator is operable over a range of frequencies sufficient to support both normal full power operation, and reduced power operation of the microprocessor. The LC oscillator minimizes clock jitter problems and so permits extension of the microprocessor operating frequency to even higher levels than heretofore were possible. An output signal from a phase-frequency detector is a frequency control signal on a frequency control input line of a level converter and filter circuit of the LC oscillator. The output signal from level converter and filter circuit is a filtered frequency control signal on a control voltage input line to a continuously modifiable gigahertz frequency voltage controlled oscillator (VCO) circuit.

Abstract: A clock recovery system that allows recovery of a clock signal from a high speed, potentially small amplitude data stream. The invention uses a normally avoided property of a non-linear oscillator in the clock recovery system in order to lock the oscillator in phase to an incoming signal. This property relates a characteristic of an oscillator that an oscillator amplifies noise near its inherent frequency; and if the noise is large enough, the oscillator squelches the inherent oscillator frequency signal and outputs a signal locked in frequency and phase to the noise. The clock recovery system comprises a processing circuit, an oscillator, and a control circuit. The processing circuit processes an input data stream to generate a current signal as a first control signal based on data transitions in the input data stream. The first control signal is a "noise signal" to the oscillator.

Abstract: A phase error cancellation apparatus captures data bits of a serialized data stream with reduced phase error by aligning a generated clock signal to the data stream. The phase error cancellation apparatus includes a data delay pipe, a clock generator, a clock delay pipe, and a data stream sampling element. The data delay pipe receives the data stream and delays the data bits by a first amount. The clock generator generates a clock signal that the clock delay pipe delays by a second amount. The data stream sampling element receives the delayed data bits and the delayed clock signal, and samples the delayed data bits using the delayed clock signal to recover the data bits from the data stream with reduced phase error.

Abstract: An on-chip resistance to an input current of an input signal includes a parallel transistor resistor and a control circuit for biasing the transistors of the parallel transistor resistor. The parallel transistor resistor includes first and second transistors of first and second types. Each transistor includes first and second current handling terminals and a control terminal. The control terminals are coupled to receive control signals from the control circuit. The first current handling terminals are coupled to provide an input node for receiving an input signal, and the second current handling terminals are coupled to provide an output signal. The control circuit is coupled to provide the first and second control signals for biasing the respective first and second transistors so that a first derivative of a resistance of the parallel transistor resistor in relation to an input-to-output voltage is zero at a selectable operation point.

Abstract: In a charge pump the noise due to switching transients on the input pulse lines is kept to extremely low levels by translating input up/down pulses into small signal differential pulses which swing a differential pair of transistors by a small amount. This is done with level converters. The differential pair is kept in a saturation region, so that a large swing is not needed from the level converters and channel creation/destruction noise is avoided in addition to the noise reduction due to smaller swings. To avoid inherent offsets which might require a nonzero delta time width difference in the input pulses to produce a zero delta current, identical differential structures are used at the inputs for the two input pulse signals.

Abstract: In a sample-and-hold circuit, an input is tracked at an output during a tracking period and the input is held during an holding period, the tracking period and holding period defined by a clock signal input to the sample-and-hold circuit, wherein the output is a differential output having a positive output node and a negative output node with the output signal represented by a voltage difference from the negative output node to the positive output node. During the tracking period, an equalizing transistor between the output nodes is turned on to bring the output to a common mode level for the output. During the holding period, the equalizing transistor is turned off and a regenerative circuit drives the output nodes apart, thus amplifying the input signal.

Abstract: A CMOS integrated circuit regulator for mixed mode integrated circuits reduces digital switching noise through use of a clamped dual source follower circuit and a charge reservoir bypass capacitor. Relatively constant current is provided to the CMOS logic during transitions to minimize switching noise.

Abstract: A driver includes first and second input terminals for receiving first and second input voltages, respectively, of a differential input signal, first and second switches coupled to the first and second input terminals, respectively, third and fourth switches coupled to the first and second input terminals, respectively, first, second, third and fourth current references coupled to the first, second, third and fourth switches, respectively, first second, third and fourth current mirrors coupled to the first, second, third and fourth current references, respectively, a first output terminal coupled to the first and third current mirrors, and a second output terminal coupled to the second and fourth current mirrors.

Abstract: An active inductor oscillator includes a tank circuit for generating a first differential signal, a common-mode inverting differential buffer for generating a second differential signal in response to the first differential signal, and an integrating circuit for generating a third differential signal in response to the second differential signal. The third differential signal is applied to the tank circuit, and lags the first differential signal. A differential transistor pair in the tank circuit provides active inductance in response to the third differential signal, and a cross-coupled transistor pair in the tank circuit provides negative resistance that amplifies the first differential signal in response to the first differential signal. Currents through the tank circuit, buffer, and integrating circuit are essentially identical to one another and move in unison with an externally applied reference current that controls the oscillation frequency.

Abstract: A cascoded cmos differential delay element is described. The delay element provides a controlled delay useful in forming voltage controlled oscillators or other circuits. The delay element provides high gain enabling it to be useful in multistage delay element circuits. The circuit described includes cascoded complementary differential amplifiers and replicated bias clamps.

Abstract: A serial data to parallel data converter is disclosed which has the advantage of accurately converting high frequency serial data to parallel data while using clock signals operating at a relatively low frequency. A low bit error rate is achieved by avoiding the use of multiple high speed clock lines typically found in other converters. The simplified circuit design also has the advantage of requiring minimal semiconductor layout area and reduced power requirements. One embodiment includes a buffer, a first data delay line, coupled to receive serial data from the buffer, and a phase lock loop (PLL), coupled to receive serial data from the buffer. A second data delay line is configured as a voltage controlled oscillator (VCO) within the PLL. The PLL locks onto the incoming serial data signal and provides a control signal back to the first data delay line to ensure it is storing serial data bits as they arrive.

Abstract: A terminating element is connected between the terminating ends of a transmission line pair. A switching mechanism coupled to the originating ends of the transmission line pair steers a constant current through the transmission line pair. In response to input control signals, the switching mechanism steers the constant current in a complementary fashion into one of the lines of the transmission lines pair to creates a differential output voltage across the terminating element. Controlling the differential voltage by manipulating current flow allows for acurate control over V.sub.OH and V.sub.OL levels. Since the terminating element is connected between terminating ends of the transmission line pair, nearly all of the constant current flowing the driver contributes to the differential output voltage, thereby reducing power undesirable power dissipation.

Abstract: An efficient high-speed ECL to CMOS logic converter for BiCMOS integrated circuits. In one embodiment, a differential amplifier compares an ECL input signal to an ECL reference voltage and generates a pair of complementary intermediate signals on a corresponding pair of differential output nodes. The differential amplifier has two load resistors coupled in series with a common load resistor which limits the upper voltage swing at the differential output nodes. A regenerative stage coupled to the differential output nodes switches between a partially on state and a fully on state in response to the complementary intermediate signals. A pair of inverter stages convert the complementary intermediate signals into a pair of CMOS level signals. A pair of complementary output drivers coupled to the respective complementary inverter stages provide current driving capability.

Abstract: A circuit for detecting multiple address matches in an associative array includes a match current generator that responds to active match signals generated by the associative array by generating a match current that is linearly proportional to the number of active match signals generated by the array. A reference current source generates a reference current that is between one and two times greater than the match current when a single active match signal is generated by the associative array. A comparator compares the match current and the reference current and generates an active output signal when the match current is greater than the reference current.

Abstract: The present invention provides an ECL to CMOS level translation circuit which uses a dynamic, internally generated reference voltage to translate ECL level signals into CMOS level signals. The translator includes an input translation circuit which uses emitter-follower bipolar transistors for receiving and interpreting the ECL level signals and to generate the dynamic, internally generated reference potential, and an output circuit for outputting the CMOS signals.

Abstract: A multi-port, BI-CMOS memory cell is disclosed having a CMOS flip-flop, one or more write ports gated by n-channel FETs, and one or more ECL read ports. Bipolar transistors in the read port are resistively interconnected to equalize emitter voltages during write and standby operations and to resistively isolate the emitters during a read operation.

Abstract: A circuit which provides additional drive current during substantially the entire transition of an output signal from a logical one to a logical zero state, thereby causing the pulldown transistor in the TTL output stage to rapidly turn on, providing increased switching speed between logical one and logical zero output state for a given power consumption. Alternatively, for a given switching speed, power consumption is reduced.

Abstract: In accordance with the teachings of this invention, a novel PLA row driver circuit is provided which utilizes a minimum number of components, thereby minimizing integrated circuit surface area, and thus reducing cost, and minimizing stray capacitance, thereby increasing speed of operation. Furthermore, in accordance with the teachings of this invention, a circuit is provided which, while utilizing a minimum number of components, provides a first VOL level to the row line during normal operation of the device, and a second, higher VOL level to the row line during programming.