Abstract: A track-and-hold circuit is provided. This track-and-hold circuit is adapted to track an analog input signal and hold a sampled voltage of the analog input signal at a sampling instant for processing by other circuitry, in response to a track signal that alternates with a hold signal. Preferably, the track-and-hold circuit includes a bi-directional current source that sources and sinks current through a first output node and a second output node, a unity gain amplifier that is coupled to first and second output nodes of the bi-directional current source and that receives the analog input signal, a resistor coupled to an output of the unity gain amplifier, and a capacitor coupled between the resistor and ground. Of interest, however, is the bi-directional current source, which includes a differential input circuit that is adapted to receive the track signal and the hold signal and that is coupled to the first and second output nodes and an RC network that is coupled to the differential input circuit.

Abstract: A track-and-hold or sample-and-hold (S/H) circuit for an analog-to-digital converter (ADC) is provided. A difference between the disclosed S/H circuit and conventional S/H circuits is the use of a peaking circuit. This peaking circuit generally provides increased current to switching transistor when transitioning between track and hold which can increase the Spurious-Free Dynamic Range (SFDR) as low frequencies, by as much as 15dB.

Abstract: An apparatus is provided. The apparatus comprises a first bipolar junction transistor (BJT) differential pair having a first BJT and a second BJT, a second BJT differential pair having a third BJT and a fourth BJT, a first clamp having a fifth BJT and a sixth BJT, and a second clamp having a seventh BJT and an eighth BJT. The collector and base of the third BJT are respectively coupled to the collector and base of the first BJT, and the collector and base of the fourth BJT are respectively coupled to the collector and base of the second BJT. The bases of first, second, third, and fourth BJTs receive an input clock signal. The emitters of the fifth and sixth BJTs are coupled to the collectors of the first and third BJTs, while the emitters of the seventh and eight BJTs are coupled to the collectors of the second and fourth BJTs. The bases of the fifth and seventh BJT are adapted to receive a low clamping voltage, and the bases of the sixth and eighth BJTs are adapted to receive a high clamping voltage.

Abstract: A switched current source is provided. The switched current source is generally comprised of transistors and resistors, and the source has a high output impedance. Included with the switched current source is an error correction transistor and a resistor that cooperate to feed a current back through a bias transistor to correct an error that generally results from the current gains or ?'s of transistors within the switched current source. To accomplish this, however, the resistor is selected to have a value that is sufficiently large such that current from the error correction transistor flows back through the bias transistor.

Abstract: A circuit and method for evaluating serializer deserializer (SERDES) performance that is particularly advantageous when the SERDES has a decision feedback equalizer (DFE). In one embodiment, the circuit has a data processing path and an operational feedback loop coupled to said data processing path and containing an equalizer, perhaps a DFE. In that embodiment, the circuit includes an eye scanning circuit coupled to said data processing path but separate from said equalizer and configured to measure at least one dimension of an eye relative to which said equalizer is configured for operation without substantially affecting said operation.

Abstract: Various systems and methods for comparing signals are disclosed herein. For example, some embodiments of the present invention provide comparator circuits with a preamplifier circuit, a latch circuit and a current re-use circuit. The current re-use circuit applies a current to the preamplifier circuit during a transparent phase, and applies a similar current to the latch circuit during a latch phase.

Abstract: One embodiment of the present invention includes a data transmission system. The system comprises a data transmitter that provides a plurality of data bits over at least one data line. The data transmitter comprises a clock that provides a clock signal associated with timing for latching the plurality of data bits and a data encoder configured to encode error data associated with the data transmission system in the clock signal.

Abstract: A track-and-hold circuit is provided. This track-and-hold circuit is adapted to track an analog input signal and hold a sampled voltage of the analog input signal at a sampling instant for processing by other circuitry, in response to a track signal that alternates with a hold signal. Preferably, the track-and-hold circuit includes a bi-directional current source that sources and sinks current through a first output node and a second output node, a unity gain amplifier that is coupled to first and second output nodes of the bi-directional current source and that receives the analog input signal, a resistor coupled to an output of the unity gain amplifier, and a capacitor coupled between the resistor and ground. Of interest, however, is the bi-directional current source, which includes a differential input circuit that is adapted to receive the track signal and the hold signal and that is coupled to the first and second output nodes and an RC network that is coupled to the differential input circuit.

Abstract: A track-and-hold or sample-and-hold (S/H) circuit for an analog-to-digital converter (ADC) is provided. A difference between the disclosed S/H circuit and conventional S/H circuits is the use of a peaking circuit. This peaking circuit generally provides increased current to switching transistor when transitioning between track and hold which can increase the Spurious-Free Dynamic Range (SFDR) as low frequencies, by as much as 15 dB.

Abstract: An improved latched comparator, including a track mode circuit, a latch and a latch and track select circuit. The track mode circuit includes two transistors having their sources connected together, and their respective gates receiving a respective first and second input, and their drains connected to the power supply by respective resistors. The latch includes a further two transistors having their sources connected together, a gate of each connected to a drain of the other, and their drains connected to a respective one of the common connection node of the first transistor and the first resistor, and the second transistor and the second resistor.

Abstract: Various logic gates and methods for using such are disclosed herein. For example, some embodiments of the present invention provide parallel differential logic gates. Such logic gates include two or more differential input pairs. The collectors of the first transistors in each of the differential pairs are all electrically coupled to an upper voltage via a first load resistor. Similarly, the collectors of the second transistors in each of the differential pairs are all electrically coupled to an upper voltage via a second load resistor. Depending upon the relative values selected for the first and second load resistors, the gate operates as an AND gate or an OR gate.

Abstract: An equalizer comprises a sampler, a filter, and a summer. The sampler samples a signal indicative of an input communication signal to determine digital decision output signals having a communication device data rate. The filter receives digital decision output signals from the sampler and generates equalization signals therefrom. The summer couples to the sampler and the filter and combines together the input communication signal with the equalization signals. Further, a plurality of clocks control timing associated with the sampler. These clocks have frequencies that are less than the predetermined data rate of the digital decision output signals.

Abstract: One embodiment of the present invention includes a data transmission system. The system comprises a data transmitter that provides a plurality of data bits over at least one data line. The data transmitter comprises a clock that provides a clock signal associated with timing for latching the plurality of data bits and a data encoder configured to encode error data associated with the data transmission system in the clock signal.

Abstract: Various logic gates and methods for using such are disclosed herein. For example, some embodiments of the present invention provide parallel differential logic gates. Such logic gates include two or more differential input pairs. The collectors of the first transistors in each of the differential pairs are all electrically coupled to an upper voltage via a first load resistor. Similarly, the collectors of the second transistors in each of the differential pairs are all electrically coupled to an upper voltage via a second load resistor. Depending upon the relative values selected for the first and second load resistors, the gate operates as an AND gate or an OR gate.

Abstract: Various systems and methods for comparing signals are disclosed herein. For example, some embodiments of the present invention provide comparator circuits with a preamplifier circuit, a latch circuit and a current re-use circuit. The current re-use circuit applies a current to the preamplifier circuit during a transparent phase, and applies a similar current to the latch circuit during a latch phase.

Abstract: A filter includes a tap multiplication circuit and a tap digital-to-analog (“DAC”) unit coupled to the tap multiplication circuit. Further, a plurality of clocks are provided that control timing associated with the tap multiplication circuit and that permit one tap multiplication to be output while another tap multiplication is being computed for a 1/N rate implementation.

Abstract: A differential driver includes two feedback loops 20 and 22, and two inverter pairs 24 and 26. The two feedback loops 20 and 22 regulate the source voltages for the two inverter pairs 24 and 26 to the reference voltages VREFHI and VREFLO. The two inverter pairs 24 and 26 switch the output load RL and CL between the two regulated voltages in response to the input voltages IN+ and IN−. The reference voltages VREFHI and VREFLO are created by a reference cell and set the output high and low voltages.

Abstract: The differential driver consists of two feedback loops 20 and 22, and two inverter pairs 24 and 26. The two feedback loops 20 and 22 regulate the source voltages for the two inverter pairs 24 and 26 to the reference voltages VREFHI and VREFLO. The two inverter pairs 24 and 26 switch the output load RL and CL between the two regulated voltages in response to the input voltages IN+ and IN−. The reference voltages VREFHI and VREFLO are created by a reference cell and set the output high and low voltages.