National Semiconductor Corporation

Laurence Douglas Lewicki

Ion E Opris

Nicolas Nodenot

Arlo Jame Aude

Jitendra Mohan

Amit Rane

Yongseon Koh

Benjamin Clyde Buchanan

Amjad T Obeidat

Devnath Varadarajan

James B Wieser

Vijaya G Ceekala

Ramsin Michael Ziazadeh

Shu-Ing Ju

Kern Wai Wong

Alan Erik Segervall

Abu-Hena Mostafa Kamal

Pak-Ho Yeung

Lee L Stoian

Manoj N Rana

George Edmond Seiler

Circuitry for adaptive signal equalizing with coarse and fine boost controls by providing multiple serially coupled stages of parallel controllable DC and AC signal gains with coarse and fine gain controls provided across all stages.

Adaptive signal equalizer with segmented coarse and fine controls

Method and system for adaptive signal equalizing with alternating boost and amplitude controls. In accordance with one exemplary embodiment, data signal boost control is based on measured equalized and sliced data signal energies within a bandwidth disposed about a higher frequency, while sliced data signal amplitude control is based on measured equalized and sliced data signal energies within a bandwidth disposed about a lower frequency.

System and method for providing adaptively equalized data signal with alternately adjusted data signal boost and sliced data signal amplitude

System and method for adaptive signal equalizing in which overlapping data signal equalization paths provide cumulative data signal equalization to provide multiple equalized data signals having different available amounts of equalization. Signal slicing circuitry slices the equalized data signals to provide multiple sliced data signals, from which the sliced data signal selected as an output data signal is dependent upon the data rate of the incoming data signal.

System and method for adaptively equalizing data signals with higher and lower data rates

A system and a method are disclosed for providing a parameterized analog feedback loop for continuous time adaptive equalization that incorporates low frequency attenuation gain compensation. N adaptive equalizer stages are coupled in series and a slicer circuit is coupled to the last (Nth) adaptive equalizer stage. A single equalizer adaptation control loop controls the frequency response of the adaptive equalizer stages to compensate for the attenuation of a lossy channel. The single equalizer adaptation control loop also compensates for the direct current (DC) loss in the lossy channel by modulating a bias current in the slicer circuit to scale the low frequency feedback with adaptation coefficients that correlate with channel length.

System and method for providing a parameterized analog feedback loop for continuous time adaptive equalization incorporating low frequency attenuation gain compensation

A system and method is disclosed for providing a clock and data recovery circuit with a fast bit error rate self test capability. A bit error rate test control unit is provided that causes the clock and data recovery circuit to sample data adjacent to an edge of a bit period to create errors at a relatively high bit error rate. This is accomplished by intentionally introducing an interpolator offset in a phase position of a data clock signal. The test control unit generates a first bit error rate and then subsequently generates a second bit error rate. The test control unit then uses the values of the first and second bit error rates to extrapolate a value of bit error rate for the clock and data recovery circuit that corresponds to a zero value of interpolator offset.

System and method for providing a clock and data recovery circuit with a fast bit error rate self test capability

A system and method is disclosed for providing a clock and data recovery circuit with a self test capability. A test control unit is provided that causes the clock and data recovery circuit to continuously alter a phase of an interpolated clock signal. A user selects a preselected bit pattern that causes the digital control circuitry of the clock and data recovery circuit to advance or retard the phase of the interpolated clock signal. The test control unit compares the advanced or retarded phase of the interpolated clock signal with a reference clock signal to determine a frequency difference between the two clock signals. The test control unit uses the frequency difference to determine the test status of the clock and data recovery circuit.

System and method for providing a clock and data recovery circuit with a self test capability

Power management for a computer system and device is accomplished by implementing two separate power modes in a serially-connected device, and selecting from the two power modes depending on the state of a receiver in the device. A signal detector within the receiver is connected to a serial interface port of the device to detect the presence of an input signal. A power controller selects a first power mode for the device when the signal detector detects the input signal and a second power mode for the device when the input signal is not detected by the signal detector.

Device and computer system for power management using serial link connections

A system and method is disclosed for providing a clock and data recovery circuit that comprises a low jitter data receiver. The low jitter data receiver comprises a phase interpolator, an amplifier unit and a data sampling comparator. The phase interpolator and the amplifier unit provide the data sampling comparator with a single ended clock signal that is relatively immune to power supply noise. The data sampling comparator samples an input data stream with minimal jitter due to power supply noise. The data sampling comparator consumes less static power than a current mode logic D flip flop and also has output levels that are compatible with complementary metal oxide semiconductor (CMOS) logic.

System and method for providing a low jitter data receiver for serial links with a regulated single ended phase interpolator

A system and method is disclosed for providing a fast turn on bias circuit that permits a fast transition from an idle 'power down' state to an active 'power up' state in current mode logic (CML) transmitter output circuits. The invention comprises a capacitor coupled to a bias transistor and a charge switch circuit for controlling the operation of the capacitor. The capacitor has a value of capacitance that is equal in magnitude and opposite in sign to the Miller coupling capacitance in the bias transistor. The capacitor compensates for the Miller coupling capacitance within the bias transistor in less than ten nanoseconds. This permits a CML transmitter to more quickly restart the transmission of data after an active state has been initiated.

System and method for providing a fast turn on bias circuit for current mode logic transmitters

An operational amplifier having a low impedance input and a high current gain output. The operational amplifier comprises: 1) a first N-channel transistor having a source coupled to the low impedance input of the operational amplifier; 2) a first constant current source coupled between the source of the first N-channel transistor and ground; 3) a first amplifier stage having an input coupled to the first N-channel transistor source and an inverting output coupled to a gate of the first N-channel transistor; 4) a second amplifier stage having an input coupled to a drain of the first N-channel transistor and an output coupled to the high current gain output of the operational amplifier; and 5) an internal compensation capacitor coupled between the input and the output of the second amplifier stage.

High speed high current gain operational amplifier

A band-gap reference circuit with averaged current mirror offsets is provided that includes a differential amplifier circuit, a low current transistor circuit, a high current transistor circuit, and a configuration circuit. The differential amplifier circuit includes a first input node operable to receive a first input signal, a second input node operable to receive a second input signal, and an output node operable to generate an output signal based on the input signal difference. The low current transistor circuit is coupled to the differential amplifier circuit and is operable to receive the output signal and to generate the first input signal based on the output signal. The high current transistor circuit is coupled to the differential amplifier circuit and is operable to receive the output signal and to generate the second input signal based on the output signal. The configuration circuit is coupled to the low current transistor circuit and to the high current transistor circuit. The configuration circuit is operable to configure the band-gap reference circuit for a plurality of states by switching a plurality of components between the low current transistor circuit and the high current transistor circuit at specified intervals.

Band-gap reference circuit with averaged current mirror offsets and method

Three-state binary adders are disclosed for use in pipelined analog-to-digital converters. According to one advantageous embodiment, a three-state binary adder is provided for use in a digital signal processing system. The three-state binary adder is operable to generate binary codes consisting of three states, namely, '00', '01' and &#x201c;10.&#x201d;

Three-state binary adders and methods of operating the same

There is disclosed a test multiplexer having over voltage protection for use in integrated circuitry, along with methods of operating the same. An exemplary test multiplexer according to one embodiment of the present invention includes a plurality of MOSFET devices and over voltage protection circuitry. The plurality of MOSFET devices, including both p-type and n-type MOSFET devices, cooperate to pass an input signal to an output signal line of the test multiplexer while the test multiplexer is enabled. The over voltage protection circuitry is biased so that a difference between the input signal voltage and a bias voltage does not exceed breakdown when the test multiplexer is disabled. An important aspect hereof is that the test multiplexer is compliant to input voltages that exceed the positive supply rail, and is capable of sustaining a high or otherwise out of threshold single ended voltage at the input without latching up.

Over voltage protection test multiplexer and methods of operating the same

There is disclosed a comparator comprising: 1) a first comparison circuit capable of receiving an input signal, wherein the first comparison circuit is enabled and compares the signal when a received LATCH signal is enabled and is disabled when the received LATCH signal is disabled; and 2) a second comparison circuit coupled to the input signal in parallel with the first comparison circuit, wherein an input stage of the second comparison circuit is substantially identical to an input stage of the first comparison circuit. The second comparison circuit is enabled and compares the input signal when the received LATCH is signal is disabled and is disabled when the received LATCH signal is enabled.

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Sunnyvale, CA, United States of America

Laurence Douglas Lewicki